Laboratory simulation of an air-curtain rood for the Ontario Science Centre

r

0'

February, 1975

LABORATORY SIMULATION OF AN AIR-CURTAIN ROOF FOR THE ONTARIO SCIENCE CENTRE

{l

7

JULI 1975

by

A. A. Haasz, B. Etkin, R. T. Lake University of Toronto

Institute for Aerospace Studies

and

P.L.E. Goering, Architect

UTIAS Technica1 Note No. 192

LABORATORY SIMULATION OF AN AIR-CURTAIN ROOF FOR THE ONTARIO SCIENCE CENTRE

by

A. A. Haasz, B. Etkin, R. T. Lake University of Toronto

Institute for Aerospace Studies

P.L.E. Goering, Architect

Submitted February, 1975

Acknowledgement

This investigation was carried out jointly, in close cooperation, by \

the University of Toronto Institute for Aerospace Studies and the Ontario Science Centre. The contributions of Dr. Peter Anderson, Messrs. Grant Slinn, Ron Miller and Don Trollope of the Ontario Science Centre are greatly appreciated.

Financial support for the project was provided by the Ontario Science Centre and by the National Research Council of Canada under Grant No.

Al894.

Abstract

A laboratory simulation with a scaled-down model of the Ontario Science CentTe was performed in order to study the effectiveness of an air-curtain roof in preventing rain and snow from entering the court yard at the Ontario Science Centre. Precipitation was simulated with solid glass beads of 53-74 ~m nominal

diameter range. In order to optimize the protection feature of the air-curtain, a variety of jet configurations were investigatèd. The determination of power

requirements and other jet parameters as functions of the impinging precipitation penetrating the air:..: curtain roof was necessary before a full-scale implementation could be considered. For the co-flowing and counter-flowing wind directions, configurations were arrived at that would require about 600 HP in the jet to eliminate 9Cf1/o of the "simulated rain"; these configurations are not considered optimum and a reduction in the power requirements is anticipated.

1. 2.

3.

4.

5.

6.

., TABLE OF CONTENTS Acknowledgement Abstract INTRODUCTION MODELLING CONSIDERATIONS

2.1 Limitations of the Simulation

2.2 Interpretation of the Collection Function EXPERIMENTAL FACILITY AND PROCEDURES

3.1 Precipi tation Wind Tunnel and Bead-Feed Apparatus

3.2

Model of Ontario Science Centre

3.3

Precipitation Simulating Material

3.4

Experimental Techniques

JET CONFIGURATIONS AND WIND FLOW FIELDS

4.1

Jet Nozzle Configuration

4.2

Wind Flow Field

PRESENTATION AND DISCUSSION OF RESULTS

5.1

Jet Elevation: h

5.2

Jet Exit Angle: á

5.3

Use of Gutters

5.4

Jet Thickness: T

5.5

Wind Direction: ~

5.6

Downstream Airfoil and Flap

5.7 Entrainment Augmentation

5.8

Downstream Reattachment and the Dual-Jet

5.9

Full-Scale Results CONCLUSIONS REFERENCES PAGE ii i i i 1 1 2 2 3 3 3

4

4

4

4

6 6 6 6 7 7 7 7 8 8 8 9 10

1. INTRODUCTION

Investigations into the possible uses of air-curtains for separating internal and external environments were initiated at the University of Toronto, Institute for Aerospace Studies in 1968 (Refs. 1 to 7). Our report deals with a laboratory simulation s tudy performed in the UTIAS precipitation wind tunnel in order to determine the feasibili ty of a full- scale implementation of an air-curtain roof for the court yard at the Ontario Science Centre in Toronto. The region which is to be protected from rain and snow has a quasi-rectangular plan (approximately 40 ft x 60 ft) and is s urrounded by walls of about 30 ft height on all four sides as shown in Fig. 1. In the present study, the

feasibility of protecting this space by a horizontal air jet blown across the top of the cavity was investigated. The performance of the simulated air-curtain roof was evaluated in terms of its effectiveness in preventing a specified

fraction of the precipitating particles from penetrating the curtain.

If a full-scale version of the studied air-curtain roof were implemented it would provide, for the first time, an opportunity to correlate laboratory

simulation results with full-scale fi:eId measurements.

The laboratory experiments were performed during the summer of 1973 and the results obtained were first presented in an internal report to the Ontario Science Centre in November, 1973.

2. MODELLING CONSIDERATIONS

In order to enable the projectionGof results obtained in laboratory simulation experiments to full-scale systems it is essential that the two systems be dynamically similar. From the non-dimensional equations of motion of' preci-pitating spherical particles in an arbitrary flow field, subjected only to

aerodynamic drag, gravitational and inertial forces, one observes that dynamical similarity is preserved by keeping the following non-dimensional groups of

parameters constant. 7T l kL/m ( 1) 7T₂ gL/V2 ( 2) where 2 k

=

(1/8)C D P 7T d p , ( 3)

CD being the drag coefficient and dp the diameter of the particle; p is the density of the air jet which is characterized by a dimension L. The quantity V is velocity , g is the acceleration due to gravity and m is the particle mass, while Pp is the particle density. However, it should be noted that the analysis

that yields these results (Refs. 5 and 8) only applies to particles moving independently of each other; also, the effects of velocity gradients in the jet were neglected.

Another simplification can be obtained for particles falling in still S;ir at terminal velocity V t • That is,

/ /

Consequently, 7T l can be expressed as 7T = kL = gL = 7T. ( y - ) 2 1 m V 2 2 V_t t (5)

Hence, full-scale and model experiments will yield dynamically similar results if the following modelling laws are satisfied.

(1) = gL =

~

C

E-

~

= constant

7T 1 V 2 '"+ D P

p

dp

t

(6)

From this condition it also follows that V

t must be proportional to ~.

(2) ~ _V - constant

t

-This requires the flow velocities (wind W and jet V.) to scale with the particle terminal veloci ty and hence with

.JL.

J

(3) Kinematic similarity is required between the full- scale and model flow fields; this condition is effectively met if the geometries are similar and if the jet velocities are proportional to the wind velocities. 2.1 Limitations of the Simulation

As discussed in Ref.

7,

true dynamical similarity cannot be achieved in particle-fluid flow interaction experiments. The present simulation must be considered in the light of the following:

(1) Neither the jet in the model nor the simulated rain drop Reynolds numbers we re full-scale. In the case of the jet, however, the effect is likely to be small since even at low values of model Reynolds numbers the jet flow will be turbulent. Incorrect "drop" Reynolds numbers are also not thought to be serious since using the correct V

t allows for the main effect of Reynolds number.

(2) Actual rain drops are deformable bodies - this may lead to development of lift forces which would not occur for rigid spheres. Furthermore, rain drops break up when the aerodynamic forces exceed the surface tension forces holding the drop intact. The significance of omitting drop deformability in the experiments is now known, but is thought to be conservative.

(3) _{The distribution functions for real rain drop Vt and simulated rain drop}

Vt should be "similar" in the mathematical sense. This is of course not the case in these experiments.

2.2 Interpretation of the Collection Function

The collection function statement !::.C/!::.C_o

=

0.05 is to be interpreted

as:

"5%

of the mass of the material impinging on the air-roof actually

.

.

'

\

Assuming that the limitations discussed in Sec. 2.1 do not markádlY alter the L.C/bC_{o function, what is the correct interpretation of be/beo}

f

~

r

real rain? In view of Item (3) in Sec. 2.1 i t cannot simply be stated thát

5%

of the impinging rainfall (by mass or volume) will penetrate the jet. However, with some reservations the results can be interpreted as follows:

(a) For a rainfall rate of 0.5 mm/h (light rain) we know from Ref. 9 that essentially all the raindrops have terminal velcc i ties less than Vt max (nom). The quantity Vt max (nom) is the full-scale terminal velocity corresponding to the nominal maximum terminal veloci ty in the simulating material. Thus for this case we shall say that be/beo = .05 means that

5%

of the imp inging rainfall penetrates the air roof.

(b) At higher rainfall rates less than 100% of the raindrops are in the nominal full- scale terminal velocity range. For example, at a rainfall rate of 2 mm/h (medium rain) 13% of the water volume lies in drops with terminal velocities greater than Vt max (nom). For this case we cannot say what fraction of the drops with Vt above Vt max (nom) will penetrate the air-roof. It is likely that the fraction penetrating in this range is higher than the measured L.C/L.Co ' However, the tendency for large drops to break-up may compensate for this effect.

3 • EXPERIMENTAL F ACILITY AND PROCEDURES

3.1 Precipitation Wind Tunnel and Bead-Feed Apparatus

The wind tunnel employed in these experiments was the UTIAS Aerolab Precipitation Wind Tunnel which has a working test section of 42 inch x 42 inch cross-sectional area and operates in the 0-10 ft/s speed range. The "preci-pitation" feature of the tunnel consists of a vibrating sieve mechanism by which the simulating material enters the tunnel through the roof. This mechanism is described in Ref. 8 and a modification is detailed in Ref. 7. 3.2 Model of Ontario Science Centre

The physical scaling (geometry) was determined in part by the availability of the appropriate precipi tation simulation material and the maximum model dimensions compatible with the exis ting UTIAS Precipi tation Wind Tunnel. A 1:150 scale model of the lower section of the Ontario Science Centre shown in Fig. 2 was employed in the tests. Tt was necessary to include at least this much of the structure surrounding the cavity so that the flow field in the neighbourhood of the jet exit would be reasoriably similar to the full-scale situation. Model velocities were scaled according to Froude's number as given in Eq.

(6),

yielding

(Vt ) full-scale

(v

t) model full-scale _Lmodel

=

~

=

12.25. ( 8) As can be seen from the photograph in Fig. 2, the intake for the

blower was connected to an air intake on the model roof to simulate a "realistic" air flow on the roof U]?stream of the nozzle assembly. The jet flow was suppliecl

by a variable speed centrifugal blower. Volume flow to the jet was determined by the use of an orifice plate downstream of the blower exit; the orifice plate was designed in accordance with specifications in the ASME Flow Meter Corrrputation Handbook (Ref. 10). The mean jet velo city at the jet exit was then corrrputed from the equation of continuity. A rough velocity survey with a hot wire anemometer indicated the presence of a reasonably uniform velocity profile at the jet exit and confirmed the mean velocity as determined from the orifice plate pressure drop measurements.

In order to facilitate the measurement of the precipitation simulating material penetrating the air-curtain roof, the court yard on the model was fitted with a removable metal box (see Fig. 2).

Schematic diagrams of the nozzle exit and the air supply scheme to the nozzle are shown in Figs. 3 and 4, respectively. A photograph of the nozzle exit, shown in Fig. 5, indicates that glass beads entering the horizontal air-curtain roof are deflected downstream by the jet.

3.3 Precipitation Simulating Material

As in previous annular jet experiments, small glass beads were errrployed to simulate rainfall. The nominal diameter range chosen for the present experi-ments was 53-74 flm (Microbead Corporation, Class IV-C No. 2027, Density 3.99 g/cm3). The terminal velocity of the beads thus lies in the range 1.1 - 1.8 ft/s, which corresponds in this investigation to a full-scale rainfall with terminal veloeities in the range 13.5 - 22 ft/ s. Tt can be noted that for a moderate rainfall rate of 2 mm/h about

85%

of the water volume is in drops with terminal velocities less than 22 ft/ s.

3.4 Experimental Techniques

The aim of these experiments was to obtain the non-dimensional

collection functions for a variety of jet and model configurations (as will be described in Sec.

4).

This was accorrrplished as follows:

(a) A fixed weight of the, glass beads was loaded into the bead-feed mechanism with the wind on (jet off). This was run through the feeder and the amount collected in the cavity (court yard) was removed and weighed on a Mettler Automatic balanee • This procedure was repeated several times

(for each jet configuration) and the mean value of the collected glass beads during the several runs was designated Deo'

(b) step (a) was repeated with jet velocity at some value Vj' The weight of material collected was designated 6C(Vj).

(c) Steps (a) and (b) thus yielded the required collection function 6C(V.)/6C = f(V.).

J 0 J

4. JET CONFIGURATIONS AND WIND FLOW FIELDS 4.1 Jet Nozzle Configuration

Since little is known about the optimum jet configuration for the horizontal roof application, a variety of "augmented" jets were investigated.

Some of these configurations were decided upon prior to the experiments while others arose from the results obtained during the experiments themselves. Although not all of the augmentations proved to be successful, significant improvement on the basic configuration was clearly obtained.

The jet nozzle geometry can be described for these experiments by the jet thickness T, jet elevation h, jet exit angle ex and the jet width w. A schematic diagram showing the pertinent jet parameter is given·.in Fig. 6. For these parameters the following values were used during the experiments.

Parameter Simulation Study Full-Scale

Jet thickness: T 8.13 mm 4.0 ft

9.78 mm 4.8 ft

Jet elevation: h 3.18 mm 1.56 ft 6.35 mm 3.12 ft

Jet exit angle: ex 150- l5~

250' 25°

Jet width: w 11.8 cm 58.1 ft

In addition to variations in the geometric parameters of the jet nozzle, three other classes of augmentation were tried.

(1) The first of these was an attempt to increase the air supply to the undersurface of the je t in order to delay the downs tream reattachment. This was achieved by allowing air originatifig from the ambient s tream in the tunnel (far away from the jet so that no perturbations in the

jet were introduced) to flow into the cavity interior through a slot under the jet nozzle as shown in the schematic diagram of Fig. 7.

(2) The second augmentation arose from the observation that the majority of the particles penetrating the jet did so near the far downstream

_ (from the jet exit) wallof the cavity. This augmentation consisted of fitting narrow gutters to the downstream wall in order to catch these particles. The gutter dimensions were fixed (Model: 7.6 mm wide,

9.4 mm deep; full-scale: 3.75 ft wide, 4.63 ft deep) but the location of the gutters was varied from top, to middle, to bot tom of the down-stream wall.

(3) Th€1..,final class of augmentations consisted of attempts to prevent or delay reattachment of the jet on the surface of the building downstream of the court yard. These augmentations consisted of modifications to the jet exit and installations of various airfoils and barriers downstream of the court yard.

Details of these modifications together with the improvements achieved are presented in Sec. 5 under Presentation and Discussion of Results.

4.2 Wind Flow Field

No attempt was made to simulate the actual flow in the vicinity of the Ontario Science Centre since no full-scale data was available and, in addition, because of time limitations on the research program.

A boundary layer was constructed in the tunnel via a barrier plate and roughness blocks but this served only to generate some turbulence to aid in the dispersion of the beads. No measurements were made of the mean velocity profile or the turbulence intensity profile.

Although two wind speeds (W

=

0, W = some reasonable wind) had been considered, i t was practical, because of a clumping problem. wi th the beads at W

=

0, to carry out the experiments only at wind speeds greater than zero ft/ s • A wind speed of W = 2.5 ft/s was employed throughout the investigation; this corresponds to a full- scale wind speed of 31 ft/ s (approximately 21 mph).

Three wind directions were employed in the experiments; namely ~

=

0°, l80~~and

90o/(see Fig. 2). The ~ = 0° corresponds to the co-flowing case while

~

=

1800 and 900represent counter-flowing and cross-wind cases, respectively. 5. PRESENTATION AND DISCUSSION OF RESULTS

The large number of experimental parameters considered in these experiments prohibi ted inves tigation of all their possible interactions in the available time. Thus, certain configurations were investigated for only one or two values of the other parameters. For example, jet elevation was investigated only for a single value of the jet exit angle. Clearly, from these results the optimum values for the parameters cannot be determined. However, the effect of the various augmentations can be seen clearly enough, and promising augmentations can be easily separated from those which are less promising.

5.1 Jet Elevation: h

Figure 8 presents the collection function for three jet elevations. It is apparent that some jet elevation is useful. Beyond a certain point, however, further elevation (particularly at high speeds) does not result in further improvement. This is reasonable in view of the fact th at the glass bead trajectories asymptotically approach vertical lines. It should be noted that in all of the figures the values of the jet parameters are given for both the model and the full-scale configurations; the full-scale values are given in brackets.

5.2 Jet Exit Angle: ex

From Fig. 9 it can be seen that the jet exit angle has little effect on the collection function, at least at high jet velocities. This may be due to the reattachment of the jet, although previous numerical computations for

5.3

Use of Gutters

Figure 10 indicates that the gutters offer an effective mechanism for decreasing the penetration without any further power expenditure. The optimum location of the gutters (how high on the downstream wallof the cavity) clearly will depend on wind speed, jet speed and the drop diameter distribution in the impinging rainfall. Although some sort of optimum location should exist, the current results only indicate that location is significant.

5.4

Jet Thickness: T

From Fig. 11 i t i s clear that significant improvement is obtained by using a jet thickness of

4.8

ft full-scale rather than

4

ft full-scale. The 10% collection level is achieved for the

4.8

ft jet for V_j

=

109 ftjs and for the

4

ft jet at 140 rtjs with gutters for both cases. The relative power requirements for the two jet thicknesses are thus

5.5

Wind Direction: ~ HP

t4

ft) HP

4.8

ft) 8.cj8.C ~ 1.7 0.1 o

Two aspects of Fig. 12 are significant. First, the drastic

difference between the cross-flow case and either the co-flowing or counter-flowing cases. Tt is expected that this difference (due to the bending of the jet) could be overcome by a simple increase of the jet width and some form of low barrier parallel to the side edges of the court yard. Addi tion of gutters on the court yard sides would also be useful.

The second thing to note in Fig. 12 is that the counter-flowing case is more readily handled than the co-flowing one. This probably s tems from the fact that in the counter-flowing case the jet does not attach on the downstream wall. This, however, requires further investigation.

5.6 Downstream Airfoil and Flap

In an attempt to delay separation an airfoil was placed downstream of the court yard. From Fig. 13 i t can be seen that this did not result in any significant reduction in the penetration. However, in Fig. l~ there are three data points which indicate (for the ~

=

1800

case) that the presence bf a·. downstream "flap" is definitely effective in reducing the penetration. This effect was not observed for the ~ = 00

case. A brief consideration of the flow for the counter-flowing case yields a reasonable argument for expecting less penetration of the falling glass beads. W

4

V.

J

As shown in the above diagram, the effect of the curved flap is to deflect the jet upwards. For the ~ = 1800

case, the wind bends this upwardly directed jet to form a "quasi double-jet" over the cavity region. This provides an effectively "richer" jet, similar to the dual-jet case which will be briefly discussed in Sec. 5.8.

5.7 Entrainment Augmentation

Since the delay of downstream reattachment was felt to be beneficial, and since this delay can be controlled by increasing the entrained air volume on the lower·side of the jet, modifications (shown in Fig. 7) to this effect were made very early in the experiment. During the lat ter stages of the project, the effect of this entrainment augmentation was investigated. The results , presented in Fig. 14, indicate that the jet with entrainment

augmentation (virtually all of the runs herein are "augmented") performed less effectively than the un-augmented jet. Thus the results obtained under augmentation are bound to be somewhat conservative. At present, it is not elear what might have caused the observed effect in Fig. 14.

5.8 Downstream Reattachment and the Dual-Jet

The reattachment of the jet downstream of the court yard has a deleterious effect on the "roof" performance. Reattachment severely

mitigates the influence of jet elevation and jet exit angle. It would seem then that a relatively free jet is to be preferred to an attached one. This ean be accomplished by using either very large h or

a

(near 90~). The first of these is clearly uneconomical and the second simply does not work for low wind velocities or in the counter-flowing case. Another way of achieving the same end is to use a combination of a vertical jet and a horizontal jet (see Fig. 15). This has been experimented with briefly and the results are clearly encouraging. However, the relative veloci ties and flow volumes of the two

jets for optimum performance are not in any way known.

Observation of the dual-jet (using smoke and the beads) indicates a flow pattern as shown in Fig. 15. Further experimentation is required in order to determine to what extent the effective jet thickness can be controlled through the variation of the relative velocities and volume flows.

5.9 Full-Scale Results

Figure 16 indicates the approximate full-scale power requirements as a function of the fraction of precipitation penetrating the "roof". It is evident that velocities of the order of 100-120 ft/s will be required. This means a total volume flow of about 28,000-35,000 ft3/s (about 1.7-2.1 million CFM). Probably some sort of ejector system will be needed to supply this large volume flow; although large axial fans would be sufficient. A total installed power of 800-1000 HP should be sufficient, allowing for losses in fans, ducting, etc.

It should be noted that the power requirements will depend on the precipitation intensity so that higher rainfalls may result in somewhat higher power requirements. However, this effect may not be significant since the effect of an increase in rainfall intensity increases the fraction of water volume in bigger drops. There is, however, an upper bound on the size of raindrops.

6.

CONCLUSIONS

(1) For the co-flowing and counter-flowing wind directions, configurations were arrived at that could be the basis of a potentially successful installation, that would require about 600 HP in the jet to eliminate

9Cf'/o

of the simulated rain (see Sec. 2.2 for meaning of "simulated rain") •

(2) The design parameters arrived at for the above cases are not considered

optim~ and it is expected that further research would lead to further

improvement.

(3) Very little effort was expended on the cross-wind case (one day of

testing), and no acceptable solution was found in the tests for this case.

(4) In view of (3), we are not prepared at this time to recommend that

the full-scale installation should proceed.

(5) Much was learned during the course of the experiments. For example, the power required for the co-flowing case in the configuration finally

arrived at was only about

1210

of that needed for the starting

configura-tion (for 8CJ1fo protection). Several new concepts were developed during

the work that would need a substantially modified model to investigate

fully. We recommend that the investigation continue with a re-worked

model, with two object~ves:

(i) to 'solve' the cross-wind case,

1. 2.

3.

4.

5.

6.

8.

9.

10. Etkin, B. Korbacher, G. K. Etkin, B. Goering, P.L.E. Graham, W. B. Allen, G.A.S. Lake, R. T. Etkin, B. Allen, G.A.S. Lake, R. T. Lake, R. T. Etkin, B. Harting, A. Mason, T. REFERENCES

Towards Dynamic Structures - Thoughts about Feasibility. Architecture Canada, 46, No. 3 (March 1969).

Air-Curtain Walls and Roofs - !Dynamic! Structures. Phil. Trans. Roy. Soc. Lond. A, 269, 527 (1971).

Jet-Stream UIDbrella. B.A.Sc. Thesis, Engineering Science, University of Toronto

(April1970).

Experimental Investigation of an Air-Curtain for Protection of an Outdoor Power Installa-tion from Salt Spray. UTIAS Tech. Note No. 171 (Aug. 1971).

The Penetration of Rain Th~ough an Annular Air-Curtain Dome. UTIAS Report No. 163

(Aug. 1971).

Trajectories of Raindrops in a Jet Issuing

Into aNormal Crosswind. UTIAS Tech. Note No. 165 (Nov. 1971).

Experimental Simulation of the Interaction of Wind Driven Precipitation With an Annular Air-Curtain Dome. UTIAS Tech. Note No. 182

(March 1973).

The tJrIAS Precipi tation Wind Tunnel. UTIAS Tech. Note No. 181 (Sept. 1972).

"The Physics of Clouds", Appendix B: !The Physical Proper ties of Freely Falling Rain-drops! •

"ASME Flowmeter Computation Handbook", The American Society of Mechanical Engineers, New York (1961).

COURT - YARD

FIGURE

I.

SCHEMATIC DIAGRAM

OF ONTARIO

LIJ 0:

....

Z LIJ (,) LIJ

o

Z LIJ

o

Cl)

o

0:

~

Z

o

LL

o

..J LIJ

o

o

:E

.

(\J

THIS SECTION CONNECTED TO PLENUM FOR JET--~--~

-.L /J--~

1rt===========~---~~~~-

----~

483an-t-2J6cmlCll3cm \ . - - - 7.12cm

FIGURE 3.MODEL JET NOZZLE

1.9Ocm

LIJ 0::

....

Z LIJ

o

LIJ

o

Z LIJ

o

Cl)

Q

0::

~

Z

o

z

o

LIJ -l N N

o

Z f-LIJ

,

~SS'l

\ y..\c'f.

~

\~~~ ~

0<. (JET

ANGL.~

:

~--.lL---.1---BOTTOM OF JET NOZZLE h (JET ELEVATI ON)

T

COURTYARD

FIGURE 6. BASIC JET PARAMETERS

COURTYARD

t

t

1....-'...o~..I-..L.-t,

"-AIR):,LOW TO CAVITY (This chamber is connected tot\,lnnel) CROSS SECTION

-1

ROOF

o

4

_... 0.4 o <3 ~ i= o ~ ~ i= o ~ ~ o O. ~ 0.2 iii _z lIJ ~ Ö I Z o z 0.1 T. 8.13mm(4.01l.) W' 2. 5f lis .<31 tvs) a:;: 150 /3. O· • h.O.OOmmIO.OOIl) • h '3. 18 mmll .5611) Q'h = 6.35 mml3. 1211) h=3.18mm EI"Olion-h~ roof • -.-.

~~

• • • 0.01'----'---'---.J'--_...J... _ _ ..I..-_--'-_ _ --'-_---.J 90 110 130 150 170

FULL-SCALE JET VELOCITY (ftl.)

FIGURE 8. EFFECT OF JET ELEVATION ON COLLECTlON FUNCTION o

4

0 .4 ... o <3 z o ï= o Z :::l u.. 0.3 ~ ~ o lIJ ..J d o ;:l 0.2 ~ (J) Z lIJ ~ Ö I Z ~ 0.1 T=8.13mm 14.011) h=3.18mm( 1.5611) W=2.5f1/sI3111/s) /3=0· o • ----.:::::,. • • O.OL---'----L--'----L--..I..--~----'---..I 100 120 140 160

FULL-SCALE JET VELOCITY (ftl.)

r--- --- --- -- - ---~o ~

!

_...

0.4 ~ 0.3

~

~ ...I ~ U o.

I

::I i5 I 0.1

i

T·8.13mm(4.0It) h '3.18mm ( 1.56ft) W '2.5 It/s( 3Ift/s) a-Is· {3'0· o no gutter. • gutter. at midpoint • gutt .... at top A gutt .... at bottom

G:

---

_, gulter , WITHOUT GUTTERS

•

O.O ' ' - - - - ' - - - . l . . . . - - - ' - - - L - - - ' - - - . l . . . . - - - ' - - - l 100 120 140 160 180

FlLL-SCALE JET VELOCITY (ft Is)

F1Gt.H: la EFFECT OF GUTTERS ON COLLECTlON FUNCTION

h'3.18mm (1.56ft) W'2.5ft/s (3Ift/s) a=15· {3. O· • T'9.78mm(4.81t) no gutter. a T·9.78mm(4.8ft) with gutt, ... o • T-8.13 mm(4.0It) na gutter. ~ O. 0 T'8.13mm(~.0ft) with gutIer.

~

I

IL O.

!

₁

0 . 2 i5 ~

~

0.1 o o 0.0'----7.L.0--90..L---'1I0---I30':-:--...,..15~O:---I7~O=---I....L90.,---...1

FULL-SCALE JET VELOCITY (ft Is)

T-9.7Smm(4.S ft) h -3.ISmm(I.56ft) O.~ W-2.5 ft/s (3Ift/s) a-15° o

.8

0.4 ~

v {3=90° (no Qutto,. on sido woll)

o {3= O· (no gult ... )

U <] 15

ti

o. ~ 15 j::: In -J iS U 0.2 -J c ~ ti) Z 1&.1 2

iii

0.1 z o z o ,B =ISOO(no ~ttors.flop) • ,B ·ISOO(~ers.flop)

*

(3 ·ISOO(without flap) o • (3 = 0 ° (gulters) (Refer to Sec. 5.6) 0 D

• •

O.O~---'----'---'-_---L_--'--_---L _ _ .l...-_-l 80 90 100 110 120

FULL-SCALE JET VELOCITY(ftl,)

FIGURE 12. EFFECT OF WIND DIRECTION ON COLLECTION FUNCTION

T-S.13mm (4.0ft) ... h -3.ISmm (1.56ft) W-2.5ft/s (3Ift/s) a-15° • U 0.4 ~ :j 0.2 0.1 {3=0" • Airfoil in ploce o Nooirfoil • 0 ~ • 0 0 i e ~ _• 0 OD~-~--.l...---L----~---L----~---J---J 100 120 140 160 180

1

0 .2 ~ ëS I Z o z 0.1 T=8.13mm (4.0fl) h=3.18mm ( 1.56ft) W=2.5 flls (31ftis) a= 15·

/3=

O· w~arr.~T7

L

EJmlAINMENT M':"CATION . : o

•

•

o.oL----
~0-0----~--~12-0----~---1~4-0----~--~16-0--~ FULL- SCALE JET VELOCITY (ft Is)

FIGJRE 14. EFFECT OF ENTRAIt-HENT MODIFICATION ON COI...LECTION FUNCTION

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0.4

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0.3

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0.2

8

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I

z

o

z

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=

2.·5ft/s (31 ft Is) T= 9. 78mm(4.8ft) h =3.18 mm(I.56ft)

a=

15°

fj=

0° with gutters

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O.O~I

____

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____

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____

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~L_ _ _ ~ _ _ _ _ _ J I

60

80

100

120

i

~ULL-SCALE J~T

VELOCIT:<ft/S)

I I

200

400

600

800

1000

FULL- SCALE JET POWER (HP)

UTlAS TECHNICAL NOTE NO. 192

Institute for Aerospace Studies, University of T oronto LABORATORY SIHULATION OF AN AIR-CURTAIN ROOF FOR THE QNTARIO SCIENeE CENTRE

A. A. Haasz, B. Etkin, R. T. Lake, P.L.E. Goerinq 10 pages

1. Air Jet 2. Air-Curtain 3. Precipitatien 4. Wind TunnelS. Glass beads

1. Haasz, A. A" Etkin. B., Lake, R. T" Geering, P.L.E. 11. UTIAS Technical Note No. 192 A laboratory simulatien wi th a scaled-down model of the Ontario Science Centre was performed

in order to study the effeetiveness of an air-curtain roof in preventlng rain and snow trom

entering the courty'ard at the On-tario Science Cent re • Precipitation was simulated with solid

glas!; beads of 53-74 )Jm nominal diameter range. In order to optimlze the protectien feature

of the air-curtain, a variety of jet configurations were investigated. The determination of power requirements and other jet parameters as functions of the impinging precipitation penetrating the air-curtain roof was necessary before a full-scale inplementation could ba

considered. For the co-flowing and counter-flowinq wind directions , configurations were arrived at that would require about 600 HP in the jet to eliminate 90\ of the '''simulated

rain" i these configurations are not considered optimum and a reduction in the power

require-ments 1s anticipated.

~

UTlAS TECHNICAL NOTE NO. 192

Institute for Aerospace Studies, University of T oronto

IABORATORY SIMUIATION OF AM AIR-CURTAIN ROOF FOR TUE ONTARIO SCIENCE CENTRE A. A. Haasz, B. Etkin, R. T. Lake, P.L.E. Geering 10 paqe.

1. Air Jet 2. Air-Curtain 3. Precipitation 4. Wind Tunnel 5. Glass beads

I. Haasz( A. A., Etk!n, B., Lake, R. T. , Goerinq, P.L.E. II. UTlAS Technical'Note No. 192

A laboratory simulation with a scaled-down model of the Ontario Science Centre was performed

in order to study the effectiveness of an air-curtain roof in preventing rain and snow from

entering the court yard at the ontario Science Centre. Precipitation was simulated with solid

glas6 beads of 53-74 lJm nominal diameter range. In order to optimize the protection~feature

of the air-curtain, a variety of jet configurations were investigated. The determination of power requirements and other jet parameters as functions of the impinging precipitation penetrating the air-curtain roof was necessary before A tull-scale implementation could be

considered. For the co-flowing and counter-flowing wind directions , configurations were arrived at th~t would require &bout 600 HP in the jet to eliminate 90\ of the "simulated

rain"; these confiqurations are not considered optimum &nd a reduction in the power

require-ments is anticipated.

~

Available co pies of ~his repor~ are limi~ed. Re~urn ~his card ~o UTIAS, if you require a copy. Available copies of ~his repor~ are limi~ed. Re~urn ~his card ~o UTIAS, if you require a copy. UTIAS TECHNICAL NOTE NO. 192

Institute for Aerospace Studies, University of T oronto LABORATORY SIMULATION OF AN AIR-CURTAIN ROOF FOR THE ONTAAIO SCIENCE CENTRE

A. A. Haasz, B. Etkin, R. T. Lake, P.L.E. Geering 10 pages

1. Air Jet 2. Air-Curtain 3. Precipitation 4. Wind Tunnel 5. Glass beads

I. Haasz, A. A., Etkin, B., Lake, R. T. e Goering, P.L.E. Il. UTIAS Technical Note No. 192

A laboratory simulation with a scaled-down model of the Ontario Science Centre was performed

in order to study the effeetiveness of an air-curtain roof in preventing rain and snow from entering the court yard at the Ontario Science Centre. Precipitation was simulated with solid

9lass beads of 53-74 IJm nominal diameter range. In order to optimize the protection feature

of the' air-curtain, a variety of jet configurations were investigated. The determination of power requirements and other jet parameters as functions of the imp inging precipitation

penetrating the air-curtain roof was necessary before a full-scale irrplementation could be

considered. For the co-flowing and counter-flowing wind directions , configurations were

arrived at that would require about 600 HP in the jet to eliminate 90\ of the "simulated

raio"; these configurations are not considered optimum and a reduction in tbe power

require-ments is anticipated.

~

Available copies of th is report are limited: Return this card to UTIAS, if you require a copy.

trrIAS TECHNICAL NOTE NO. 192

Institute for Aerospace Studies, University of T oronto

IABORATORY SIMULATION OF AN AIR-CURTAIN ROOP FOR THE ONTARIO SCIENCE CENTRE A. A. Haasz, B. Etkin, R. T. Lake, P.L.E. Gearing 10 pages

1. Air Jet 2. Air-Curtain 3. Precipitation 4. Wind Tunnel 5. Glass beads

I . Haasz, A. A., Etkin, B., Lake, R. T., Goering, P.L.E. 11.' UTIAS Technical Note No. 192

A laboratory simulation with a scaled-down model of the Ontario Science Centre was performed in order to study the effeetiveness of an air-curtain roof in preventinq rain and snow from

entering the court yard at the Ontario science Centre. Precipitation was simulated with solid

qlass beads of 53-74 lJm nomina 1 diameter range. In order to optimize the protection feature

of the air-curtain, a variety of jet configurations wera investigAted. The determination of

power requirements and other jet parameters as functions of the impinging precipitation penetrating the air-curtain roof wAS necessary before a tul I-sc ale implementation could he

considered. For the co-flowing and counter-flowinq wind directions , configurations were arrived at that would require about 600 HP in the jet to eliminate 90\ of the "s1mulated

raio"; these confiqurations are not considered optimum and a reduction in tbe power

require-ments is anticipated.

~