Design algorithm for energy conversion- and
distribution systems of submarines
February 1995
CONCEPT PERFORMANCES 1 object dimensioningon,
TU Delft
Main Electric Motor object dimensioning
BALANCES
Battery object dimensioning
E.M. Pei
OEMO 95/11
Diesel generator object dimensioning! Propeller object dimensioning Energy conversion object dimensioning object dimensioning,
MUO
HydraulicHigh pressure air Electric DC Electric AC Heat Space Weight, Propulsion Energy conversion-)
LIST OF CONTENTS
page
PREFACE 3
FUNCTIONAL DECOMPOSITION LEADING TO OBJECTS 7
HOTELLOAD 13
ELECTRIC LOAD BALANCE 19
HIGH PRESSURE AIR BALANCE 97
HYDRAULIC OIL BALANCE 107
COOLING WATER BALANCE 121
WEIGHT & DIMENSIONS OF THE ENERGY CONVERSION EQUIPMENT 131
MODEL VERIFICATION 147
REFERENCE LIST 162
SUB-ENERGY
eli - CONCEPT .PERFORMANCES _ Propulsion Energy conversiobp
1 object dimensioningMain Electric Motor object dimensioning BALANCES Battery object dimensioning Diesel generator object dimensioning Propeller object dimensioning Energy conversion object dimens onin
In
object dimensionind
SUB GEM
'Hydraulic
High pressure air
Electric DC
Electric AC
Heat
Space Weight
PREFACE
This report (SUBENERGY = SUBmarine ENERGY systems) is concerned with the
deter-mination of the "Hotelload" and the deterdeter-mination of "object models" for energy conversion systems of submarines.
The HOTELLOAD is defined as the total electric energy consumption of the auxiliary sys-tems of the underwater vehicle. This hotelload is required in the submarine performance
calculations of the SUBPROP-project (SUBmarine PROPulsion system) [Pe1,1995].
The performance is defined as the measure of fulfilling a defined function. The submarine performance model concentrates on the functions of the boat as a whole. Functions such as
Range and (submerged-)Endurance.
An "object model" has been defined as a collection of numerical relations (based on
scientific principles and "existing design" information) which describes on one hand the characteristics of a group of components (such as weight, dimensions,energy consumpti-on) within the object and on the other hand it's functional requirements (the capacity of the object, such as the power output of an electric motor).
Objects are defined as building blocks having space, weight and energy demands, which can be located at once within a boat. An object can contain one or more components. A component is a group of equipment having the same function. Components are at the deepest level of interest for the designer and therefore components are the basic building blocks in the design. Components are of a size that can be expected in the ships dispositi-on plans (examples of compdispositi-onents are : pumps, compressors, fans etc.).
The reasons for this investigation are that
The energy balances given in figure 0.1 are of great importance to the performance of the submarine. All these balances lead to the total hotelload and that is an
important (especially at slow speeds of the submarine). However these energy
balances itself are also important parameters in the ship performance. For example an excessive consumption of High Pressure (HP)-air will have an influence on the submerged range of a submarine. For a large amount of HP-air is needed to surface
the submarine.
the energy conversion systems are important factors in the determination of the size of the submarine, and the size of the submarine determines the power requirement
for a sufficient level of overall submarine performance and hence we encounter a loop in the design
Energy conversion a Hotelload
The main function of the "energy conversion" systems is to provide the submarine (underwater vehicle) of the required electric-,hydraulic-, and pneumatic energy and to provide the submarine of the required cooling capacity (chilled water plant). The energy conversion systems represent a great deal of the hotelload (energy
con-sumption of the auxiliary systems) and the dimensions of the energy conversion systems depend on this Hotelload.
Figure 0.1 gives a clear picture of the different levels within this project. On top we find the submarine performances, in the middle the dimensions of the objects forming energy
conversion , and at the bottom we find the energy balances. All these levels are connected
to each other The SUBENERGY project is a separate research project within SUBCEM,
the development of a SUBmarine Concept Exploration Model (SLTBCEM) at Delft
Uni-versity of Technology [v.d Nat, 1993]. The SUBCEM will be used to make concepts for new underwater vehicles, and it will also explore existing underwater vehicles. SUBCEM is a knowledge base filled with numerical relations and contains several models like SUB-SPACE (a computer program that controls the arrangement of the submarine model). A knowledge based computer program called QUAESTOR [Hees, 1991], is used to manage
this knowledge.
The area of validity of the "object models" described in this report concern conventional underwater vehicles, within the range of 1000-3000 ton submerged displacement, and a range of 20 - 80 crew members. Exceeding these ranges can cause (significant) errors in the results of object models. The word "conventional" in submarine terms means that the underwater water vehicle is equipped with batteries for the energy storage and diesel generator sets to recharge these batteries. Unconventional submarines are submarines
equipped with nuclear power plants.
This research starts with the determination of the objects forming energy conversion. For this determination a functional decomposition strategy is used. This functional decom-position strategy is described in Chapter 1 of this report.
After the determination of the most significant components of energy conversion the "object models" have to be determined. Because "object models" consist of numerical relations based on scientific principles and "existing-design" information, for the determi-nation of these "object models" the following activities have been carried out:
Production of a data base of existing design information Literature survey about the physical principles, on which the
behavior of components is based.
After this gathering of information the energy balances are composed, the energy
consumption depends on the operating condition ofthe submarine and therefore first these operating conditions had to defined (Chapter 2).
The electric power to all energy conversion equipment is supplied by the Direct Current (DC-) electric distribution system. Therefore all energy consumption will be translated to a DC-power consumption. So first the Electric load balance will be composed (Chapter 3). To determine the electric power consumption of the several energy conversion systems, now the energy consumption of each energy system in the defined operating conditions
will be calculated.
Chapter 4: High pressure air consumption calculations
Chapter 5: Hydraulic oil consumption calculations Chapter 6: Cooling water flow calculation
If the calculated energy consumption cannot be compensated by the corresponding energy
conversion system, the capacity of this conversion system has to be enlarged.
Next in line is the determination of weight and the space demand of the energy conversion systems (Chapter 7)
At last the SUBENERGY model is verified with the help of already built underwater vehi-cles within the ranges of validity. In this specific case data of the Dutch submarine Walrus is used (Chapter 8 ).
_
1. FUNCTIONAL DECOMPOSITION LEADING TO OBJECTS
CONTENTS
LI_ Introduction
1.2. Functional decomposition leading to "objects"
1.3. Existing decomposition methods
1.4. Composing an object from components
Ls._ Selecting the objects for energy conversion
SUB-ENERGY'
1.1. INTRODUCTION
The aim of this chapter is to derive the objects which fulfill the function "energy conversion''. Therefore the following steps to the decomposition of the boat are taken
Functional decomposition of a submarine to components Discussion of existing decomposition methods
Choice of important variables for composing an object from components - Selecting the objects for the function propulsion
Submarines are composed of many different systems, which can be elaborated in numerous ways. No standard approach is used by submarine design organizations to label and assem-ble these systems. Without deprecating any approach, the one used in this report parallels in composition and terminology the U.S. Navy's SWBS (Ship Work Breakdown Structure).
FUNCTIONAL DECOMPOSITION OF A SUBMARINE
The purpose of functional decomposition is to identify a limited number of standard components, which are of significant importance to the designer.
Within functional decomposition several levels of description are used for the location of every component, as shown in figure 1.1.
At the highest level of the functional decomposition we find the ship itself. The function of the ship as a whole can be divided in main functions. For the performance of these functions several ship systems are objected. These ship systems consist of components. These components are at the deepest level of interest to the designer. To reduce the number of items in the model the individual components are grouped into objects.
The function of the vehicle (ship/submarine) as a whole has been divided into eight main
functions.
REAL WORLD
Main functions within a submarine
The following main functions are identified Creating floating platform
Propulsion
Energy conversion
Energy distribution
Ship control
Navigation,Observation and Communication
Provision crew
Special (military-) functions
SUB CEM
Figure 1 1 : Levels of decomposition
Creating floating platform
Creating a balanced state between the enclosed volume of the ship and the surrounding,,
seawater.
-12
Propulsion
Gives the ship speed and autonomy
Energy conversion
Power conversion from DC-to AC-current, electric power to hydraulic power, electric
power the pneumatic power etc
Energy distribution
Provides in the demand for a specific form and quantity of energy at a specific place within the ship.
Ship control
Gives manoeuvrability to the ship, and control of the ship systems
Navigation, Observation and Communication
Takes care of positioning the ship, and the required interfaces with the outside world. Provision crew
Provides the crew a of living environment
Special (military-) functions
Provides in the special demands of a specific ship, such as a torpedo firing system for
military submarine.
1.3 EXISTING DECOMPOSITION METHODS
There is no standard existing decomposition method. Data bases of Walrus[Royal Nether-lands Navy] and the Seadraon [Republic of China] use the Standard Marine Structure (SMI)-terminology for this subdivision and some other existing designs, for example the MORAY[RDM] design use the SWBS subdivision
The decomposition to components used in this report is based on the terminology of the Ship Work Breakdown Structure (SWBS). Appendix A shows the SWBS-list used.
The decomposition method based on SWBS terminology is chosen for two reasons
Data bases of some existing designs are already based on the SWBS system The SWBS-list will probably be the future standard in underwater vehicle
design
I. Data bases of existing designs;
Data bases of some existing designs already use the SWBS subdivision and other sub-division methods like the SMI-system can be translated into the SWBS-system. However the components in the SWBS-list are grouped in a different way than
those in other lists. This leads to differences, in for instance, the weight calculation between the components of different ships. These differences can be explained by analysis of the components.
SUB-ENERGY
2. Future standard;
The SWBS-list will probably be the future standard. The SWBS list has been internationally accepted for underwater vehicle design. Therefore it will be easier to implement future designs into object models.
1.4 COMPOSING AN OBJECT FROM COMPONENTS
Decomposition based on the SWBS terminology leads to a great number of components. Using to many individual components makes the arrangement of the submarine, in this preliminary design stage, needlessly complicated. So grouping of components into objects, which can placed in a boat as a whole, is necessary.
Criteria for selection of objects are
Objects must contain components having the same type of object Objects must contain components having the same type of attribute Objects should to be located at once
If the number of selection criteria would increase, the number of objects would also
increase.
Object types and attributes
Objects can be divided in several types.
The type of object describes the space demands of an object, like
volume deck area
minimal required height and length We can also add one or more attributes to an object.
Attributes of objects describe special behavior of objects such as: use available space above other objects first size of object dependents on available space In SUBCEM three types of objects are defined
Object type I Object is described by length,deck-area, height and volume
Object type 2 Object is described by deck-area, height and volume Object type 3 Object is described by volume.
The attributes which can be added to objects are:
-Divided
Objects of type 2 and 3 can be separated into different parts, each part can be defined on a different location. For instance : the accommodation can be divided into a part which is located on the upper deck, and another part on
the lower deck.
-Fill up
Used for objects of type 2 and 3. The size of the object is depending on the available space in the cell. For instance: fuel tanks will fill up a space where no other objects have defined,
-Free volume included
Used for object type 3. The object can be placed above already located objects in the free volume (unoccupied volume).
-Volume between frames incl.
Used for object type 3. The volume of the object can also be placed in the space between (pressure-hull-,deck- and bulkhead-) frames.
-Orientation
Used for object type 1. The length and width (breadth) of an object can be
changed. For instance Platform Control and Monitoring system. -Margin
Objects of type 2 and 3. The size of the object is depending on the size of the totally filled cell-space in which the object is to be placed. For instance
: Service space in the engine room.
The type of data that has to be collected for the determination of the design algorithms depends on the type of object. And the design algorithms will determine a space demand and weight of an object.
1.5 SELECTING THE OBJECTS FOR ENERGY CONVERSION
The conversion systems of electric-,hydraulic-, and pneumatic energy contain subsystems each consisting of small number of relatively large components such as a HP-air
compressors , hydraulic oil plants. Following the criteria for selecting the objects as given in § 1.4
- Objects must contain components having the same type object, and Object should be located as a whole
The function "energy conversion" is divided in the following seven objects 440V-60Hz conversion system (SWBS 3142)
2. 115V-60Hz conversion system (SWBS 3143)
3. 115V-400Hz conversion system (SWBS 3144) 4. 24V-DC conversion system (SWBS 3131)
5. High Pressure(HP-)air plant (SWBS 5511)
6. Hydraulic oil plant (SWBS 5561)
2 HOTELLOAD
CONTENTS
2.1 Introduction
2.2. Survey of the hotelload
The main batteries
The MEM
vst
The main switchboard Pbufi Pvel PDG Photell PAIP
The main generators
The Hotelload
The AIP
Figure 2.1. Key elements DC-electric power system of a submarine
SUB-ENERGY
tfV
SUB CEM2.1. INTRODUCTION
In the submarine performance calculations (SUBPROP, [Pe1,1995] ) the key-elements are
mentioned of a DC-electrical power system of a submarine( see figure 2.1). The Hotelload is one of these key-elements.
The Hotelload is considered as the electrical power consumed by all auxiliary consumers of the submarine including all power conversion equipment.
The Hotelload depends on
1. The size of the 'submarine
The special functions of the submarine The number of auxiliary systems The crew number
The operating condition The environmental condition
The capacity of an auxiliary system and therefore its electrical power consumption, is related to the size of the submarine.
The kind of auxiliary systems needed is related to the special functions of the submarine. For instance a military submarine will often have a torpedo-firing
system.
The number of auxiliary systems is most of the time a choice of the user and is
related to:
- The required redundancy
- The degree of automation
- Other demands of the user, such as a separate systems
The influence of the crew number has its main effect on the "provisions crew" part
of the hotelload.
For a given submarine the instantaneous value of the power consumption of the Hotelload is strongly dependent on the operating condition. For instance in the condition "deeply submerged" the radio equipment will be on "stand-by" ( no antenna available) and therefore consume only little energy.
Environmental conditions such as the temperature and salinity differences of seawater have great influence at the power consumption of the submarine.
2
SUB-ENERGY
2 2 SURVEY OF THE HOTELLOAD
To survey the hotelload five energy balances are identified
The electric-load balance
The High Pressure air balance The hydraulic oil balance The heat balance
The cooling water balance
The heat balance of a submarine is surveyed in an separate project (SUBCOOL, [de Wit,1994] )
Each balance will be divided into
Energy suppliers Energy consumers
a The survey of the energy suppliers (energy conversion plants) are part of the
electric load balance. This balance therefore determines the hotelload, and the other balances will contribute to it.
The SWBS-object list (appendix A) will be used to identify the energy consumers
and their energy consumption.
2.3. SUBMARINE OPERATING CONDITIONS
In general four submarine operating conditions will be considered in the energy balances. These operating conditions are defined as
Patrol deep.
The condition "Patrol deep" is considered to be the fully operational submerged operating condition of a submarine. Energy for propulsion and Hotelload is supplied by the main batteries, and no energy saving measurements are taken.
Patrol snort:
The condition "Patrol snort" is considered to be the normal submerged operating condition during snorting. Energy for propulsion, Hotelload, and charging the batteries is supplied by the main generators. No energy saving measurements are taken. The submarine is fully operational. To provide the air needed to run the diesel engines and refresh the air inside of the submarine the snorting mast is raised. Several other masts are raised for reasons of navigation, communication, and observation. During this condition the operating depth of the submarine is limited to the so called "periscope depth".
Survival deep
The condition "Survival deep" is considered to be a submerged condition in which all equipment not vital for survival is shut down. This condition provides a
maximum of endurance. (chapter 3) (chapter 4) (chapter 5) (chapter 6) SUB CEM :
The MEM operating modes in this condition are "stop" or/and "(very)dead slow
ahead".
Full snort
The condition full snort is considered to be a submerged operating condition under extreme circumstances Energy for propulsion, Hotelload and charging the batteries is supplied by the main generators. No energy saving measurements are taken. The submarine is fully operational and carrying out as many operational tasks as possible. In this condition the energy consumption of the Hotelload shows a
maximum.
The conditions "Patrol deep" and "Patrol snort" are used in the performance calculations to calculate the Indiscretion Rate (IR) and Range of the submarine ( [Pel,1995] ).
The condition "Survival deep" is used to calculate the maximum endurance of the
submarine ( [Pe1,1995) )
The design condition is used in the determination of the number, volume and weight of the energy conversion equipment. This can be the condition "Full snort" or another
operating condition. The design condition is determined by the designer.
3 ELECTRIC LOAD BALANCE CONTENTS
3.1. Introduction
3.2. Electric distribution systems
3.3. Method of electric load analysis
3.4. Data collection
3.5. Electric load calculations of the electric energy consumers
3 1 INTRODUCTION
The purpose of this chapter is to come to an electric load analysis.
The results of all other auxiliary balances (chapter 4-6 and SUBCOOL [de Wit,19941)are implemented in this electric load balance. Therefore the total electric load will act as the
"hotelload".
First we will determine
Electric load suppliers Electric load consumers
The electric energy conversion systems are considered to be the energy suppliers in the electric load analysis. At the same time these conversion systems also are electric energy consumers of the Main DC distribution system The energy consumption of these systems will be calculated in § 3.6.
The electric energy consumption of the consumers is calculated in § 3.5.
3.2. ELECTRIC DISTRIBUTION SYSTEMS
Recognizing that the main batteries provide DC- power, it is understandable that a direct design solution would be, to employ standard DC-motors for all auxiliary systems and feed them directly by the main supply. However these DC-motors, capable of operation over the large voltage range associated with a battery on discharge, are significantly heavier, more bulky and expensive than an AC- motor, fed by an AC-system. Another advantage of the AC-motor is that this motor needs less maintenance.
Weapon and navigation equipment often require electrical supplies at 400 Hz for reasons
of stabilization.
Control, indication and monitoring equipments are often based on 24V-DC.
For these reasons the following electric distribution systems (fed by the DC-system)are
common on board submarines: I. 440V-60Hz
115V-60Hz 115V-400Hz
24VDC
1) The advantages of motors are already mentioned. For these reasons the
AC-motor is adopted whenever possible. To achieve the maximum cost advantage it is
necessary to use standard motors.
Power conversion from DC to 440V-60Hz can be effected by two types of
converters
Rotary converters
Electronic (thyristor) based (static-) converters
SU B-EN ERGY
CP
SUB CEM
2) The most extended electric distribution system is the of 115V -60Hz system. The
main consumers of 115V-60Hz are communications and lightning. The advantage of this system is that standard (commercial) lightning, and "provisions crew" (like refrigerators and entertainment systems) can be adopted.
Power conversion is effected by:
transformers from the 440V-60Hz system.
direct conversion from the DC system by static converters
3) A 115V-400Hz distribution system is adopted to supply energy to the weapon and
navigation equipment.
Power conversion from DC to 115V-60Hz is effected by
Rotary converters
Electronic (thyristor) based (static-) converters
4) Control, indication and monitoring equipments, essential for "safety of ship and
crew", are often based on 24V-DC. This 24V-DC distribution system can operate independent (during a limited period of time) of the main DC distribution system by using its 24V-DC (emergency) batteries. In normal conditions these batteries are
used as buffer batteries. The power demands are usually small and can be met
using:
Static converters fed directly from the main DC-system. Static converters fed from 115V-60Hz
3 3 METHOD OF ELECTRIC LOAD ANALYSIS
The electric load is systematically analyzed using a similar method as described in Klein
Woud [1993]. Table 3.1. presents this method.
table 3 1
The columns of this table contain
swbs : SWBS object number
smi : SMI object number
- ess : electrical supply system ( A= DC-power system, B=440V-60Hz
,C=115V-60Hz, D=115V-400Hz, E=24VDC, A/B means A or B depending on choice of user)
name of component
no : the number of components installed
- load the nominal electric load of one component [kW]
swbs SITU ass name of component no load Patrol
deep
Patrol snort
survival Full snort
nr/fl/f2 mill /1"2 nr/f 1/12 nriTi/12
,:
- operating condition
For each operating condition the following parameters can be distinguished
nr -
number of operational componentsthe total number of components( =no)
with nr =The operational factor (0-1)
-
instantaneous load nominal load( =load)with Fl: the load factor(0-1)
F2 -
operating time componenttotal time operating condition
with F2: the simultaneity factor (0-1)
Using this table the electrical consumption of a component in a particular operating condition can be calculated with
NO * load * nr * fl
* f2 = consumed power of component out of essThe efficiency used for an electric motor in the nominal load calculations of a component is related to the nominal electric power of this component. The values of the electric motor efficiencies are derived from table 3.2.
Table Electric motor efficiencies related to the nominal electric load.
[Hamcls, 1992] asynchronous motor - Patrol deep Patrol snort Survival - Full snort DC motor
The total electric load of each electric energy distribution system is obtained from the
i Pnom [kW] eff. [ ] 1 i 0.83 279 0.92 >,79 0.95 Pnom [kW] eff. [-] 0.06 0.58 0.,5 0.62 1.1 0.75 5.5 0.84 11 088
SUB-ENERGY
SUBCEM 8.1 81 0.89 102 0.90 Flsummation of the electric loads of all components in a particular operating condition. So P440/60tot = EP444v6o PI 15/60tot E P115/60 P115/40010t E P115/400 P24VDCtot = EP24VDC
with P440/60tot =The instantaneous total load of the 440/60 distT.system [kW]
PI1 5/60tot =The instantaneous total load of the 115/60 distr.system [kW]
P115/400tot =The instantaneous total load of the 115/400 distr.system [kW] P24VDCtot =The instantaneous total load of the 24VDC distr.system [kW]
3.4 DATA COLLECTION
The following data sources are used:
Specifications Walrus [Royal Netherlands Navy]
Tender evaluation Moray 1800 pill [Holtackers,1993]
- Power distribution Walrus [Stapersma,1983a]
- Energy balance Seadragon [de Vries,1983b]
- Electrical balance Moray 1800 pfH [de Vries,1992a] =
-SUB-ENERGY
3 = 0 09 (13 2 13bur't nomMEMm "ainlub nburstwith PnomMENtramlub The nom electric load of the MEM main lub-oil pump [kW]
PBburst =The burst power of the MEM [kW]
nburst =The rotation rate of the MEM at burst power [rpm]
The coefficient 0.09 has been matched with Walrus and Seadragon data. A value of 0.7 [k\k](Seadragon) for the nominal electric load of the main lub-oil pump can be used as a
default value.
SUBCEM
3.5 THE ELECTRIC LOAD CALCULATIONS OF THE ENERGY CONSUMERS
3 5.1. Vehicle function 200 Propulsion
The object of the function propulsion contributing to the electric load balance is -Main Electric Motor (=MEM) auxiliary system
The object 211 MEM auxiliaries
The components of the object MEM auxiliary system contributing to the electric load
balance are
- MEM (Main Electric Motor)-main lull oil system
- Propulsion control system
The other MEM auxiliary components are assumed to be accounted for in the
MEM-efficiency calculations [Pe1,1994]. MEM lub-oil system
The purpose of the MEM lub-oil system is lubricating and cooling of the bearings,so the nominal load of the components of the MEM lub-oil system are assumed to be related to the bearing dimensions (bearing length times diameter) and so to the maximum torque of the MEM. The bearing length is assumed equal to the bearing diameter ( MEM
dimensioning model [Pel, 1995] ).
The components MEM lub-oil system are
a MEM main lub-oil pump
MEM back-up lub-oil pump MEM starting lub oil pumps MEM lub-oil heater
MEM lub oil control box a. MEM main lub-oil pump
The MEM main lub-oil pump is operating during all operating conditions whenever the Main Electric Motor is running.
b. MEM back-up luboil pump
The MEM back-up lub-oil pump is only operating in emergency conditions. The nominal load (derived from Seadragon) is calculated with
3
=
PnomMEMbackuphth 0.07.
with PnomM7Mbackuplub =The nom.el. load of the MEM lub-oil back-up pump [kW]
A value of 0.5 [kW] (Seadragon) for the nominal electric load of the MEM lub-oil back-up pump can be used as a default value.
c. MEM starting lub-oil pump
The MEM starting lub-oil pump is only operating when the MEM is stopped. The purpose
of this pump is to lift the MEM rotor from its bearings to prevent bearing damage during starting of the MEM.
The nominal electric load derived from Walrus is found with:
ncmaMEMst = 033arttub
"
with PnomN1EMs dub The nom.el load of the MEM starting lub-oil pump [kW]
A value of 2.5 [kW] can be used as a default value for the electric load of the MEM
starting lub-oil pump.
For reasons of redundancy often two MEM starting lub-oil pumps are objected. d. MEM lub-oil heater
The purpose of the MEM lub-oil heater is to preheat the in the MEM lub-oil return
tank.
The lub-oil heater is not operating during normal operating conditions, then the lub-oil will be heated by the MEM itself.
Assuming that the capacity of the MEM lub-oil tank is related to the flow the
nominal electric load is found with (PBburst ]2 nburst PI3burst nbum PnoraMEMlubheater = 0.56. 3 (PBburstf
with PnomMEIvfluboilheater =The nom.el. load of the MEM lub-oil heater [kW]
A value of PnomMEMlubollheater = 4.2 [kW] can be used as a default value.
SUB-ENERGY
e. MEM lub-oil control box
The MEM tub-oil control box is operating in all operating conditions.
The nominal electric load of the lub-oil control box is copied from Moray and assumed to
be constant.
PnomMEVflubcontrol = 0*1
with PnomMEIvflubcontrol =The nom.el. load of the MEM luboil control box [kW]
Propulsion control system SWBS 2521 / STYLI 1255
The propulsion control system is always operational, even the time the MEM is not
running.
The nominal electric load of the propulsion control system is copied from Walrus and
assumed to be constant.
nomMEMPCS = 1.0
with PnornMEMPCS =The nom. el. load of the propulsion control system [kW]
SUB CEM
swbs smi es s name of component no load Patrol
deep
Patrol snort
survival Full snort
nr/flif: nr/f1/12 nr/fl/C2 nr/fiia
2351 12132 B MEM main lub pump
,
I Pnom 1/1/1 1/1/1 1/1/1 1/1/1
2351 12132 A MEM backup lub pump I Pnorn 0/0/0 0/010 0/0/0 0/0/0
2351 12132 B MEM starting lub pump Z Pnom 0/0/0 0/0/0 0/0/0 0/0/0
2351 12132 B MOM luboil heater I Pnom 0/0/0 0/0/0 0/0/0 0/0/0
2351 12132 0 MEM luboil control
box
I 0 I I/1/ 1 I/1/1 1/1/I 1/1/1
swbs snit eta name of component no load Patrol deep
Patrol
snort
survival Full snort
nr/f1/12 nr/f1/12 nr/f I /12 nr/f1/12
3.5.2. Vehicle function 300 Energy supply
The objects of the function energy supply contributing to the electric load balance are - Battery auxiliary systems
- Diesel Engine/generator auxiliary systems The object 310 Battery auxiliaries
The components of the object battery auxiliary system contributing to the electric load balance are
Battery compartment ventilation Battery cooling system
Battery agitation system Battery monitoring system
H2 elimination system capacity (PBamcnt 0.5 Pr..). (SWBS 5122) (SWBS 2232) (SWBS 2234) (SWBS 2235) (SWBS 5252)
In "snorting condition" (when the battery is charged) the battery compartment ventilation Car "
.PBanvent Pnom). Ki4.4 #1
ill be switched on high capaci
w ty ( =
The battery compartment ventilation is operating at very low capacity (NPBattvent(13 Pnorn ) during the condition "Survival deep" in order to remain just enough airflow to maintainan allowable hydrogen/air mixture.
The nominal load of the battery compartment ventilation depends on the quantity of gas production of the main battery. This gas production is related to the capacity of the battery and so the volume of the battery.
Derived from the Dutch submarine Walrus we find':
out(
(a C- Pil'aa'ttv cm"
VILRVmainbatt = 0.113.V[kW]
s.
notaBiatveut
V1ntu.WLR (Acis42,
with PnomBattvcnt = the nominal power of the battery compartment ventilation [kW]
Vmainbatt = the volume of a main battery [m3]
The number of battery fans is equal to the number of main batteries, so
NO = Z
.Battery compartment ventilation SWBS 5122 / SM1 1411
In case of lead-acid batteries the presence of hydrogen must be expected both in the battery compartments and in the battery cells. The evolution of hydrogen develops during charging the batteries and also in small quantities during discharge. If the hydrogen content of air equals or exceeds a value of 3.8 vol% the mixture of hydrogen and air becomes explosive. To avoid an explosive hydrogen/air mixture a sufficient battery
compartment ventilation is essential.
During the condition "Patrol deep" the battery compartment ventilation is switched on low
=
Battery cooling water system(SWBS 2232, SM1 12122)
The function of the battery cooling water system is Reduction of the battery temperature
Reduction of the temperature difference between the battery cells
ad a) During charging and discharging the battery , the temperature of each cell will rise.
The battery cooling water system prevents that the cells will reach the maximum temperature of 55°C . A cell temperature of 25°C is considered as an optimum.
ad b) During charging and discharging the battery, temperature differences between the individual battery cells can occur. As the cell capacity is related to the cell temperature and the fact that the total main battery capacity can be limited by the lowest capacity of only one battery-cell , local high cell temperatures have to be
minimized.
Battery cooling is effected with demineralized water. This water flows through the hollow polebridges of the battery cells. The water is re-cooled with seawater in a battery cooler. The battery cooling water system consists of
a battery cooling water pump
a battery cooler (a "cross-flow" tubular cooler)
a de-ionizer, through which a small percentage of the total flow is
circulated.
During the condition "Patrol Deep" (battery discharge) The battery cooling water pump can be operating intermittent, with F2 varying between 1/24 and 1/2 (depends on the battery discharge current lath, ) . A mean value of 1/6 for F2 seems to be realistic.
During the conditions "Patrol snort" and "Full snort" the complete nominal load of the battery cooling water pump has to be taken into account (F2=1).
In survival condition the battery cooling water system is stopped.
There are two conditions in which the total battery cooler capacity is needed
1. During burst speed, and
During full snort
Assuming that the heat loss due to the internal resistance of a main battery is about 2% of the battery power (PBa) and that in these conditions the "hotelload" is neglectable in
relation to the MEM power (PmEm PB.burs) and the generator power (P00):
swbs um eSS name of component no load Patrol
deep
Patrol
snort
survival Full snort
,
mill /f2 nr/fl/f2 nr/f112 nr/filf2
5122 1 41 I Battery comp vent Zmb 0 113
N /mb 1/0.5/1 1/1/1 l/03/1 I/1/1
SUB-ENERGY
SUBCEM a.I
H AThe required total battery cooler capacity 0battcool , related to the maximum load of the
batteries, can be found with:
if PB,burst PDG
0.02. PB,bwst
In this condition a maximum discharge current occurs during burst speed
and
if
PB,burst PDGQbatzcooi = 0.02 . 'DG
In this condition a maximum charge current occurs while snorting.
=The battery cooler capacity [KW]
=The burst (=maximum) power of the MEM [KW]
=The maximum power of the dieselgenerator plants [KW]
The required battery cooling water flow can be obtained from
Qbattcool 3600
Ckbattcool 7
bat:wool tbancoot . sw .
=The required battery cooling water flow of the pump [m3/h]
=The number of battery coolers
=The specific weight of battery cooling water (=998 ) [kg/m3]
=The specific heat of cooling water (= 4. 18) [kJ/kg°C]
=The battery cooling water temperature difference between in- and
outlet cooler (=1.2 ) [°C]
The battery cooling water temperature difference Atbattcool is determined by the main
battery ( only small temperature differences between battery cells are allowed ), and therefore can be taken as a constant in the battery cooling water flow calculations.
with Qbattcoo I PB,burst PDG with (I)battcooI Zbattcool SW C p Atbattcool
SUB-ENERGY
Assuming a pressure head (ADheadbattcool) of 1.5 JO [Pa] the nominal load °Pith& battery
cooling water pump can now be found with
(haucool ' Pworkbattcool
3600 tot.baucool
with Pnombattcool =The nominal electric load of the battery cooling pump [kW]
=The pressure head of the battery cooling water pump [Pa]
=The total efficiency of the battery cooling water pump The total efficiency of the centrifugal pump can be found from
tot,battcool battcoolpump 1battcoolc
with ribattcoolpump =The total pump efficiency (= 0.4 {Walrus))
=The efficiency of the electric motor (= 0.77 )
So the total efficiency itot,battcool becomes 0.3[-].
The number of battery cooling systems is assumed equal to the number of main batteries,
SO :
NO = Zmainbat
Puombaucool
SUB GEM
Battery agitation system ( SWBS 2234 / SMI 12124)
An uniform distribution of acid density and heat in the cell is realized by an acid circulation system. This system is based on the so-called "air-lift" principle. The needed
air is supplied from an external air compressor. The acid circulation system consists of
An air compressor (a centrifugal pump) A suction line + filters
A pressure line + filters
swbs smi ess name of component no load Patrol
deep
Patrol
snort
survival Full snort
nrif1/12 nr/f 1 /12 nr/f I/12 nr/fi/12
2232 12122 B Battery cooling syst Z
nib Pnom 1/1/ 0 167 1/1/1 0/0/0 I /1/1 = ilbancoole I APheadbancool
During the condition "Patrol Deep" (battery discharge) the battery agitationsystem will normally be operating till one hour after snorting. However at high battery discharge currents the agitation system will operate more frequently (F2 is varying between 1/24 and 1/2). A value of 1/3 for the synchronous factor F2 seems to be realistic.
During the condition "Patrol snort" and "Full snort" the battery agitation system will
operate continuously.
In "survival condition" the battery agitation system is stopped.
The acid circulation system of a cell designed in submarine battery technology is based on a circulation of the total acid volume of a cell in one hour. The airflow needed is therefore related to the battery cell volume
(Pailiift,cen Co.ruft . Vbaucell
with (t)airlift,cc11 =The needed airflow per battery cell [rn3/h]
C 4oamlift =The airflow/cell-volume ratio (=0.36(Walrus))
Vbancall =The battery cell volume
The total airflow can be found from
4)airtift,tot Zbattcell "
with it,airlift,toi =The total airflow [rn3/h]
Zbancell =The number of battery cells
The pressure head of the battery agitation compressor is related to the cell height (hBaen)
(Pstanc) and the system resistance (filter resistance, pipe resistance etc.)(Pay...):
Assuming that the dynamic pressure loss due to filters,flowmeter and piping is constant we
find
Pheadairliftpump smacid g ' hBattcell Cacidlevel Pdynamic
with Phcadamliftpum p
Mudd
hBancell Camdlev el Pdynam ic
=The working pressure of the agitation compressor [Pa]
=The specific mass of the cell acid(1310) [kg/m3]
The acceleration due to gravity (=9.81) [m/s']
=The battery cell height [m]
=The acid level correction factor(= 0.92 (Walrus))
The dynamic pressure loss (= 0.19.105(Walrus)) [Pa]
SUB-ENERGY
The electric load of the agitation compressor is calculated with
(I)liftto ' Ph dairliftpump p alr tnamairliftpump
3600 .
with Pnomairliftpump =The nominal electric load of the agitation compressor [kW]
=The total efficiency of the agitation compressor(= 0.3)
tot,airlift = lir1iftpump' airlift,e
with 11airldtpump =The efficiency of the airlift compressor(-0.4)(Walrus)
nalrlift.e =The efficiency of the electric motor of the airlift compressor(=0.75)
SUB CEM
Salinity protection system (SWBS 2232 / SMI 12122)
The battery cooling water is re-cooled with seawater in tubular coolers. The demand for a very low conductivity of the battery cooling water can only be realized by using
demineralized water as a cooling agent. Pollution of this demineralized water can be effected by small leakages of the battery coolers, in that case the conductivity of the cooling water will rise quickly. So for safety reasons there is always a salinity protection system installed in the cooling water system.
The salinity protection system consists of
A salinity measuring system Isolation valve control
The salinity protection system is always operating.
swbs sml en name of component no load Patrol
deep
Patrol snort
survival Full snort
nr1112 nr1lic2 nr,f112 nr1i12
2234 12124 13 Agitation system Z
mb
Pnom 1/1 /0.167 1/1/1 0/0/0
swbs smi eat name of component no load Patrol
deep
Patrol
snort
survival Full snort
or/fl ,f2 nr1.1 /12 nr/fl/f2 nrifi/12
2232 12122 C Salinity protection 1 0 2 1/1/1 I'1 '1 1/1/1 mil
::
I
1/1/1
nominal'
Battery monitoring system ( SWBS 2235 / SMI 12125)
The main batteries are supplied with a computer controlled monitoring system providing the following functions
continuous monitoring of the cell voltages
measuring of (dis-) charge currents of the main batteries measuring of cell temperatures
An other important variable is the acid density of a battery cell, however a reliable acid density sensor is not (yet) available.
Each main battery has its own battery monitoring system. The battery monitoring system is always operating and consumes about 1 [kW].
H2 eliminators (SWBS 5152 / SMI 1417)
If the hydrogen content of air equals or exceeds a value of 0.75 vol% , hydrogen
eliminators can be used to reduce this hydrogen content. In these circumstances the heaters of the hydrogen eliminators will be activated .
In the defined operating conditions the hydrogen evolution of the batteries will be low and no heaters have to be activated. The H2 eliminators are only used in emergency
conditionsfor example in the condition the diesel-generators are crash-stopped during an equalizing charge of the main batteries
The number of H2 eliminators which has to be installed can be obtained from
ZH2 = CEL . Zminnba Vmairthau
with ZH, = The number of H2 eliminators
CEL = The eliminator constant 0.17 (Walrus))
The nominal electric load of the H2 eliminator heaters of Walrus and Seadragon has a
value of 0.2 [kW] per heater.
swbs imi name of component no load Patrol
deep
Patrol snort
survival Full snort
or/f1/12 or/fl/f2 or/fl/f2 nr/f if 12
2235 12125 C battery monitoring syst I
m h
I 1/U1 1/1/1 1/1/1 1/1/1
swbs tirrIl eat name of component no load Patrol
deep
Patrol snort
survival Full snort
mill /f2 nr'11.1: ntlfl/f2 nr/fi/f2
5152 1417 C H2 eliminators Z
li 2
0.2 0/0/0 0/0/0 0/0/0 0/0/0
SUB-ENERGY
The object 320 Diesel engine auxiliaries
The components of the Diesel engine (DE) auxiliary system contributing to the electric load balance are
- DE preheating system (SWBS 2334)
DE aftercooling system (SWBS 2334) DE prelub system (SWBS 2334)
- Fuel oil service & conditioning (SWBS 2611) - Generator AC-heating (SWBS 2331)
- DSS system (SWBS 2522)
- DLA system (SWBS 2522) - ACS system (SWBS 2522)
Preheating diesel engines (SWBS 2334 / SMI 12114)
The diesel engines are provided with a preheating system. The purpose of this preheating system is to heat up the engine by keeping the fresh water and luboil of the diesel engine at a temperature of 40°C. A warm diesel engine can build up its maximum load in about 20 seconds, a cold engines needs more than 12 minutes.
The preheater system consists of electric heater elements. These elements are allocated in the fresh water cooling system of the diesel engine.
During the condition "Patrol Deep", the preheating system of the diesel engine will be operating after the diesel engine is cooled down (after a period of snort) to 40°C,
The preheating system is operating intermittent during this period. A value of 1/6 for F2
seems to be reasonable.
In "survival condition" the preheating system is turned off
The nominal load of the heaters is assumed to be related to the mass of the engine and therefore related to the nominal torque of the diesel generator plant (Pupa/ n).
Derived from Walrus we find
PnampEprchezt = 11.7 . with PnomDEpreheat P I DG nDG PIDG nDG SUBCEM
= The nominal electric load of the preheater [kW]
= The nominal load of a diesel generator plant [kW]
= The nominal rotation rate of the DG plant [rpm]
swbs sm : css name of component no load Patrol
deep
Patrol snort
survival Full snort
nt/f1/12 nr/f1112 nr/fl /12 nr/filf2
2334 12114 A Preheating DE Z
Dki
Glowing plugs diesel engines (SWBS 2331 , SMI 12111)
In each cylinder of a diesel engine a glowing plug is installed. The purpose of this plug is to heat up the air/fuel mixture in the cylinder during the start up procedure of the engine. The start up procedures of the diesel engines comes about during the condition "Patrol deep" just before snorting. However the synchronous factor F2 will be very low and therefore assumed to be zero.
The nominal electric load of the glowing plugs is about 0.1 [kW]
Fresh water cooling system diesel enaines ( SWBS 2334 / SMI 12114 ) Each diesel engine is provided with a closed cycle fresh water cooling system. The purpose of this system is
Cooling of the running diesel engine
After-cooling of the diesel engine (after a period of running) Preheating of the diesel engine
A fresh water cooling system consists of
A mechanically driven fresh water cooling pump A fresh water cooler
An electrical driven fresh water cooling/preheating pump An electrical driven pre-lub pump
A fresh water preheater (see SWBS 2334) A fresh water expansion tank
A fresh water after-cooler
Appendages (valves,piping etc)
The mechanical driven waterpump and the fresh water cooler are mounted on the diesel
engine and these components are only operational during the running time of the diesel
engine Therefore these components of the fresh water cooling system are considered to
be part of the diesel engine itself, and so part of the total efficiency of the
dieselgenerator plant.
The electrical driven fresh water cooling/preheating pump together with the freshwater preheater, the luboil preheater , and the fresh water aftercooler belong to the preheating/
aftercooling part of the cooling system.
The fresh water preheater is already accounted for in SWBS 2334. The luboil preheater is a freshwater/luboil heat exchanger. The luboil preheater and the fresh water after-cooler are connected in series. The fresh water preheater is connected parallel to the after-cooler, and a temperature controlled three-way valve switches the waterflow between after-cooler
and preheater.
swbs snit css name of component no load Patrol
deep
Patrol
snort
survival Full snort
, nr/fl/f2 nr/f 1 /f2 nr/f 1/f2 nr/fuT2 2331 12111 B Glowing plugs DE Z Dg 0 1 0/0/0 0,0 /0 0/0/0 00/0 :
SUB-ENERGY
The pre-luboil circulation pump stimulates the heat exchange between luboil and
freshwater and this pump is also providing the required minimum luboil starting pressure.
The preheating and aftercooling is always operational when the diesel engine is stand-by during the condition "Patrol deep".
During the "survival condition" the preheating/aftercooling is stopped.
The after cooler capacity is related to the mass of the dieselgenerator plant. Derived from Walrus and Moray we find
QaftcodDE = 59.8.
niDGDo
with Qatic ao ID E The aftercooler capacity [kW]
P1DG The nominal power of one dieselgenerator plant [kW]
nDG =The nominal rotation rate of a DG-plant [rpm]
The required cooling water flow can be obtained from
QaftcoolDE 3600 43aftcoolDE AtaftercoolDE " ' eP with ckliftcoolDE AtaftercoolDE sw cp
=The required cooling water flow [m3/h]
=The temperature difference between inlet/outlet
cooler (= 6.5 (Walrus)) [°C]
=The specific weight of cooling water (=998) [kg/m3]
=The specific heat of cooling water(418) [kJ/kg°C]
SUBCEM
In this formula the temperature difference between inlet and outlet cooler( Atnftercool) is
taken from Walrus and assumed to be a constant.
The nominal electric load of the fresh water circulation pump can be found with
(kaftcoolDE PhezdaftcoolDE
PnomaftzooLDE
3600 tot,aftcoolDE
With PnomaftcoolDE =The nominal electric load of the fresh water pump [kW] 6.P headaftcoolDE =The pressure head of the aftercoolpump [Pa] iltot,aftcoolDE =The total efficiency of fresh water circulating pump unit
The pressure head of the aftercool pump is copied from Walrus; Anh eadaf tcoolDE=0.7. 1 0'[Pa]
SW
The total efficiency of the centrifugal pump unit can be found from
tot,aftcoolDE aftzoolpurap netcool,e
with 11a ftc oo lpum p = The aftercool pump efficiency (= 0.47 (Walrus))
11a ftcoo I,c = The efficiency of the electric motor (= 0.7 )
The electrical driven pre-luboil pump is equal to the fresh water circulating pump.
In case of a low value for the luboil temperature (increased oil viscosity) the Marine Safety factor will compensate for the decreased pump efficiency of the pre-luboil pump.
Fuel oil service and conditioning system (SWBS 261] /Smi 1251)
The fuel oil can only be consumed by the diesel engine after that dirt and water is removed from the fuel. Therefore the submarine is equipped with a fuel separator
The fuel separator is running mainly in "snorting condition" to fill up the fuel oil day-tank. The synchronous factor F2 is related to the total fuel consumption of the diesel generator plants and the volume of the fuel oil day-tank ( normally the fuel level in day-tank will vary from 0.3 to 1.0 of the total volume) Depending on the size of the fuel day tank two
different operation conditions can be defined
If the fuel oil day tank is relatively large intermitted operation of the fuel separator is needed. In that case the capacity of the fuel oil separator has to be sufficient to fill up the fuel oil day-tank from 30%-100%, including compensation for a
maximum fuel consumption of the dieselgenerator plant, in about 45 minutes. If the fuel oil day-tank is relatively small the capacity of the fuel separator is matched to the maximum fuel consumption of the diesel engines in order to realize
a continuous operation.
The minimum size of a fuel oil day-tank is determined by the maximum fuel consumption of the diesel generator plants during one snorting period without a running separator.
Assuming a standard snorting period of 40 minutes we find
Vfueldaytank = FC . 0.67
with Viucidaytnk FC
The volume of the fuel oil day-tank
=The fuel consumption
swbs smi ess name of component no load Patrol
deep
Patrol snort
survival Full snort
nr/f I /f2 nr/f I /f2 nr/f1/12 nr/fi/f2 2334 12114 H I, reshwatercoohng DE Z Dg Pnom I /1/I 0/0/0 0/0/0 0/0/0 2334 12113 Il pre lub DE Z Dg Pnom 1/1/1 0/0/0 0/0/0 0/0/0 : = I
For the "hoteliload"' calculation we will consider a continuous operation of the fuel had separator
Yncinfuelscp; = Cr tor "
ZQ.FO
with Finom fuelscp =The nominal electric !load of the fuel separator [kW]
Cseparator =The specific fuel separator constant(=1.8(Walrusp IkVVh/rril
bs UM CS5
--name of component no load Patrol
deep
Patrol snort
survival Full snort
--or/ 1 I TM nr/f1/12 nr/f1 /12 nr/ri/12
2611 I 1251 B NIFueI oil seminar I Pnom 0/0/0 1/1/I 0/0/0
sw bs smi ass
1
name of component no load Patrol
deep
Patrol snort
!survival Fug snort
I nr/f I/12 nr/fl/f2 nr/fl/12 nr/fi/f2 233Ik ., 1211111 .11 I B AC-heating main generators 2 0.57 I I/7/1 0/0/0 0/0/0 0/0/0
SUB-ENERGY
SUBCEM'Generator anti-condense heating (SWBS 2331 I SMI 12T11) HI
The main generators are fitted with an anti-condense heater. This electric heaters are operating whenever the main generators are not running.
HI
Derived from Walrus, Seadragon and Moray we find
PnanACgoa = 037 [kW]
Diesel Start Stop System (DSS) (SWBS 2522/ SM1 1254 )
The diesel start/stop automatic 'MSS) is an autonomous computer system which has the
following functions
start of the diesel engines
operation of the diesel engines and snorting system stop of the diesel engines
In order to be able to execute these functions the DSS is provided with
Communication with other systems Valve control
Sensors
Each diesel engine has its own monitor and control system. The DSS is used to integrate
these control systems.
The DSS is always operational. However during the "survival condition" the DSS is supposed to be shut off.
Derived from Walrus we find
PnoinaDSS PO [kW]
with PnomDSS = The nominal load of the DSS [kW]
Sometimes the diesel engines are also provided with a less integrated Start /stop system
(Diesel Local Automatic)(then ZDLA=1 otherwise ZDLA=0 ), this system is working as a
back-up for the DSS system, and is only monitoring and controlling the diesel engines, but not the snorting system. The nominal load of the DLA-system is assumed to be equal to
the DSS
Automatic Charging System (ACS) (SWBS 2522 / SMI 1254)
The Automatic Charging System (ACS) is an autonomous computer system which is able to control the whole charging procedure of the main batteries.
In order to execute this function the ACS is provided with
Control/monitoring of the battery auxiliary systems (SWBS 310) Power control of the main generator
Communication with the Battery Monitoring System (SWBS 2235)
swbs smi cs:, name of component' no load Patrol
deep
Patrol snort
survival Full snort
nrfl'f2 nrif112 net It2 nrifi.12 2522 1254 C DSS(dIescl start/stop) ' , 11/ I/1/1 111/1 010/0 1/1/I
2522 1254 C DLA (diesel local
start/stop) Z DLA 1 0 1/1/1 1/1/1 0/0/0 VI 1,1 ,: =
SUB-ENERGY
Though each main generator is monitored and controlled separately, the ACS is an
integrated system.The Automatic Charging System is always operational. However during the "survival condition" the ACS is supposed to be shut off.
The nominal load of the ACS is taken from Walrus (Pylon,Acs = 1 {kW])
3,5.3 Vehicle function 330 Energy conversion
The objects of the function "energy conversion" contributing to the electric load balance
are
HP -air plant (SWBS 5561)
- Hydraulic oil plant (SWBS 5561)
- Chilled water plant (SWBS 5142)
The object HP- air plant
High Pressure Air plant (SWBS 5511 / SMI 1611 )
Assumptions of the calculation of the energy consumption of the HIP-air plant are - The HP-air compressors are running only during periods of snorting. - Air leakages are not included
- HP-air bottles are fully loaded (pressure 276 bar)
The nominal load of the HP-air plant is related to
The required compressor capacity
The efficiency of the HP-air plant 1) The required compressor capacity depends on
The storage capacity of the HP-air bottles
- The total air consumption
The capacity of the HP-air bottles must be sufficient to de-ballast 40% of the total volume of the Main Ballast Tanks (MBT's) at a back pressure of 0.75 times the water pressure at
maximum diving depth.
Normally this is sufficient to provide enough HP-air for at least three full' MET blows
without recharge.
SUBCEM
swbs S1711 CSS name of component no load Patrol
deep
Patrol snort
survival Full snort
nrifl/f2 nr/f11: or/fl /12 nrifit2
2522 1254 C ACS (automatic charging system) I 1/1/1 1/1/1 0/0/0 1/1/1 1 1 I 0 _____, I
The total air consumption is obtained from the AIR BALANCE calculations, as given in
Chapter 4.
The working pressure of the I-IP-air consumers are not equal. Therefore the consumed volume of HP air is expressed as the airvolume used related to an environmental pressure
of 1 [N/m2] and 273[K] also called Normal airvolume [Nm3].
NOTE ;The N in [Nrn3] stands for Normal not for Newton
2) To calculate the efficiency first the shaft power of the HP-air plant has to be calculated
with: -Pad pi .(kw k Zstages r k p, PH:Psi/aft with PliPshaft 'gad rim ech (kor P2/Pi ZsCages Ms,'
11 ad 11 mech lis,i '
tech
=The required compressor shaft power [kW]
=The adiabatic efficiency (taking into account the deviation of the
compressing process/adiabatic process,value 0.9-0.95)
The mechanical efficiency (depends on the compressor construction,with values varying from 0.85 to 0.9)
=The Normal airflow through the compressor [NtrO/h]
=The adiabatic exponent (assumed to be 1.4)
=The environmental pressure (assumed to be 1.10 [Pa]
=The pressure ratio of a compressor stage
The number of compressor stages (assumed to be 4)
=The isentropic efficiency
The pressure ratio p2/p1 is determined by steigas
\ Pbegin
with pbcgin =The suction head (=0.95. p) [Pa]
Pend The outlet pressure (=1.03 p5) [Pa]
Assuming that HPcomp mech ' e Pend with Tie PHPcomp 195.48 . (air 1 liTcomp = 9.2 [Nm3/h]
=The efficiency of the HP-air compressor
=The efficiency of the DC electric motor (-0.92)
The calculated compressor efficiency of the Compair Reavell compressor of Walrus has a
value of 0.7.
For MORAY] 800 the tender specifications of two compressors give [Holtackers , I993]:
Compair Reavell 5417N -11HPcomp= 0.7
Saner WP 5500 -ThiPcomp= 0.57
A compressor efficiency of 0.7 is taken as a default value.
We find the load of the compressor by substitution of the default value in the compressor
power equation
with PHpe.mp =The load of the compressor due to the air consumption of the HP air distribution system [kW]
The Normal air flow through the compressor can be obtained from:
4lair 4)cansum blow-off + dryer
,
with (I)consum =The HP air consumption (HPAir Balance) [Nm3/h] 4)biow_off =The air loss caused by the blow-off valves of the comp. [Nm3/h]
dryer =The air loss caused by the HP air dryer [Nm7h]
do,
Default values for blow-off and &fryer are copied from Walrus: blowoff = 1.5 [Nrn3/h]
4)dryer
SUB-ENERGY
SUB CEM=
Assuming that
-The number of HP-air compressors, and
-The nominal load of the installed HP-compressors are known, the simultaneity factor can now be calculated.
F2HPcomp PFEF'comp comp nomHPcomp
with F2HPcomp =The simultaneity factor of the HP conversion system
PnomHPcomp =The nominal load of a HP air compressor [kW] ZHPcomp =The number of HP air compressors
If F2Hpc0n,pi 1 : The nominal load of the HP air plant has to be increased,or
The number of compressors has to be increased.
The nominal electric load of the Walrus Compair Reavell compressor is PnomHPcomp=38.5
[kW].
The object hydraulic oil plant
Hydraulic oil _plant (SWBS 5561 / SMI 1541) A hydraulic oil plant consists of
- hydraulic oil return tank,connected to the suction line of the pump - a DC-driven hydraulic oil pump
- a hydraulic oil accumulator - a nitrogen bottle
- Filters in suction and pressure line
For reasons of redundancy a hydraulic system of a submarine consists of several hydraulic oil plants. Sometimes a return tank is divided in sections, each section connected to the suction line of a hydraulic pump.
A hydraulic pump of the screw type is always used, because they have the following
advantages
- Low noise production - Low pressure fluctuations
The IMO pump type D6-045 is adopted on Zwaardvis, Walrus, Seadragon and Moray,
therefore the installation of this pump is a starting point of the electric load calculations of the hydraulic oil plant.
swbs SIM eSS name of component no load Patrol
deep
Patrol snort
survival Full snort
nr11 /r2 nr/c1 /17 nrg I /12 nr/fi12
?ft II 161 I A IIP-atrplant Z Pnom 0,'0/0 I'l .1,2 0/0/0 1/1/1
;,
:
SUB-ENERGY
SUB GEMThe pump capacity varies from a value of 90 to 110[1itre/min], and therefore is assumed to
be 100[1itre/min].
The number of pumps installed depends on - The rate of redundancy
- Maximum consumption of hydraulic oil
The maximum oil consumption is obtained from the HYDRAULIC OIL BALANCE, as
described in chapter 5.
So the number of hydraulic pumps can be found with
Ckti drmax
Zhydrpump = MShydlptunp . [TRUNC( Y ) 11
'thydrpurop
with ZhYdrPumP =The number of hydraulic oil pumps
Ckhy drm ax =The maximum hydraulic oil consumption [litre/min]
(Ohydrpurn p =The pump capacity (=100) [litre/min]
MShydrpump =The marine safety factor (=1.5 (Walrus))
The redundancy is taken into account by the marine safety factor (MShy,pump), the value for
Walrus is taken as a default value.
In emergency conditions several parts of the hydraulic oil system will be isolated, in this case the switching frequency of the pump must still be acceptable to prevent thermal overload of the starting resistances.
Therefore each hydraulic oil pump has to be connected at least to one accumulator. The working volume of this accumulator is related linear to the pump capacity. Derived from
Walrus we find: \Iwo, _ 4)hYchTtimP
2.7
with 'Tworkacc = The working volume of an accumulator [litre]
Assuming an adiabatic process the working volume °fan accumulator can be calculated
with [NEVES131.5,1984]:
pi dr
=
(();
1 . p3 Thy . (f3 Vacc + Vnint)oricacc Thydrmax with P p3 Thy&
=The maximum hydraulic oil working pressure (=130) [bar]
=The minimum hydraulic oil working pressure (=90) [bar]
=The minimum pressure of the accumulator (=80) [bar]
=The adiabatic exponent (=1.4)
=The temp. of the hydr.oil in the accumulator(303) [K]
:
Pncanhydrpump
Thydrmax =The maximum accumulator temperature (=323) [K]
f, =The free play ratio of the accumulator (=0.9)
Vac, =The total volume of the accumulator [litre]
V
=Volume of the nitrogen bottle connected to the accu [litre]The hydraulic oil plants are operating in all operating conditions. The electric load of the hydraulic oil pumps depends on
- The number of pumps
The nominal load of the pumps
The switching frequency of the pumps in a specific operating condition The number of pumps to be installed depends on the required redundancy. Mostly the hydraulic system is separated into two independent systems (a "vital" and a "main system). Every system has its own hydraulic oil plant. Sometimes the steering/diving system (one of the large hydraulic power consumers) have there own independent hydraulic back-up system
For the nominal load of a pump can be taken
Existing pump A nominal load of 36[kW] (the nominal load of the IMO-D6 pump) is used as a default value for a pump with a capacity of 100 [litre/min] at
130 [bar].
Arbitrary screw pump
Assuming a constant efficiency the required normal load of an arbitrary screw pump can be calculated with:
with Pnomhydrpump APhcadhydrpump e,hydrpum p 71hydrpuni p (khydrpump PheadhYdrPuraP 1°5 103 . 60 11e,hydrpump hycirriumP
The nominal load of the hydraulic oil pump [kW]
=The pressure head of the hydraulic pump [bar]
(Pheadhydrpump (P1 +P2)/2 -Preturn , and p = 2 [bar])
=The efficiency of the electric motor (=0.88)
=The efficiency of the hydraulic screw pump (-0.63(Walrus)) In practice the hydraulic oil pumps are operating intermittent.
The pump switching frequency is obtained from
hydr
ShYdrPumP
7
1:1YdrPumP krdrrumP
with ShydrrumpThe switching frequency of the pump (0-1)
ckhydr =The total hydraulic oil consumption in an operating condition [litre/min]
-:
:
-The value of the switching frequency of the pump of the pump has to be < 1 in all
operating conditions, otherwise more pumps or pumps with an increased capacity have to
be adopted.
The hydraulic oil consumption (th ) in the different operating conditions is determined in
the HYDRAULIC BALANCE calculations.
The object chilled water plant
Chilled water plant (SWBS 5142 / SMI 1414)
A chilled water plant supplies chilled water to Air Conditioning Units and is also used for the direct cooling of high power electronic equipment.
A chilled water plant consists of - Freon compressor
Freon vaporizer/chilled water maker
condenser
The nominal load Pnomchillplant and the number of plants are obtained from SUBCOOL [de
Wit, 994].
The chilled water plant is operational in all operating conditions, except for the survival
condition.
The load factor FlchIllplant depends on the heat load of the chilled water plant in the operating conditions 1 chill'plant Qchill Qnonirhil I swbs sm 1 ens name of component no load Patrol deep Patrol snort
survival Full snort
nr/fl/12 nr'll/f2 nr1-1 ,12 nr/f i/f2
5561 1541 A Hydr.oil-plant Z hydrp Palos III IS 1/1/S 1/1/S 1/1/1
swbs sm ii ens name of component no load Patrol
deep
Patrol snort
survival Full snort
or/fl/f2 nr/f UM nr/fl/f2 nr/f i/f2
5142 1414 A chilled water-plant Z Pnom 1 /F In 1.,F1 /1 000 1/1/1
SUB-ENERGY
SUBCEMwith F1chillplant =The load factor of the chilled water plant in an operating condition
Qchill =The instantaneous heat load of the chilled water plant [kW]
Qnom =The nominal heat load of the chilled water plant [kW]
I
