Open water test series of modified au-type five bladed propeller models of area ratio 0.80

2 JUU 1981

--

_--

lab.

_{y. Scheepsbouwkun1e}

ARCHIEF

Technische Hogeschoo!

OPEN WATER TEST SERIES OF M011ifIED

AU-TYPE-FIVE-BLADED PROPELLER MODELS

OF AREA RATIO 0.80

SERIES DE TESTES EM CANAL ABERTO DE MODELOS DE HELICES DE CINCO PAS DO

TIPO A U MODIFICADO, DE COEFICIENTE DE AREA E X P A N D I D A IGUAL A 0,80.

ATSL'O YAZAXI

por/by MICHIO TAKAHASHI (*)

JUNZO MINAKATA

()

RESUMO

Este trabalho apresenta resultados de testes ne Tanque de provas do Instituto de Pesquisas Navais de Tóquio realizados sôbre urna série sistemática de modelos de hélices de cinco pás do tipo A U, propositairnente modificado.

O coeficiente de área expandida da série de modelos ficou mantido no valor de 0,80 e os diagramas relativos _aos coeficien-tes de velocidade J contra coeficiente de fôrça propulsora KT e as outras curvas, dando os outros valôres dos coeficiencoeficien-tes espe-cíficos, foram preestabelecidos através de diagramas para projetos de hélices preliminarmente determinados em outros testes.

Trata-se de um trabaiho que embora publicado em poucas páginas possui um valor de multo maier profundidade _e pene-traçâo por se tratar de um tipo de hélice de caracteristicas bem modernas e de aplicaçâo s e m p r e major, principalmente nos supernavios.

I.

INTRODUCTION

The authrs have reported the results of tank tests

on the AU-type-five-bladed propellers with the

expan-ded area ratio of 0.50 and 0.65

(1).

Further to the work, the authors conducted a

sys-tematic testing work with same type of propeller

mo-dels with the expanded area ratio of 0.80 in the Mejiro

n.° 2. Experiment Tank. In this paper, thi authors

pre-sent the results of the open water tests and the

ö design diagram.

II.

MODEL PROPELLERS AND OPEN WATER TEST

Model propellers used here are made of alminium

alloy and they have the diameter of 0.25 m. Their

principal particulars are given in Table 1, and the

model propellers are shown in Fig.l

-Open water tests were carried out in the n.° 2

Ex-periment Tank according to the ordinary practice.

To obtain the net thrust, the correction for the

re-sistance of the screw hub was made at various speed

of advance for the measured thrust.

The Reynolds number R0

of the tests are shown

in Table 1.

(')

Engineers and scientists of Ship Research Institute Tokyo,

Japan.

VOL. I - N.° 3 - JULY/SEPTEMBER 1968

Table i

Particulars of Propeller Model,

Diameter (m)

Boss Ratio

Exp. Area Ratio

Max. Blade Width Ratio

Blade Thickness Ratio

Angle of Rake

Number of Blades

Reynolds Number (Rai = nD2/y)

III.

TESTS RESULTS AND DESIGN DIAGRAMS

The results of tests are shown in Fig. 2 in the form of

J-KT ,K0

, ,

diagram. Values of KT

, K0 and 1 read

from the figure above are tabulated in Table 2.

Fig. 3 shows the

V'-

I type design diagram. In

this diagram, the metric units are used, and the

den-sity of sea water is assumed as 104.51 kgsec2/rn1.

IV. ACKNOWLEDGEMENTS

The authors wish to valuable cooperation and

as-sistance of Mr. Tadashi YAMAMOTO and the staff of

Ship Research Institute.

V. REFERENCE

(1)

_{K. Tsuchida, A. Yazaki and M. Takahashi;}

Open Water Test Series with Modern Five-Bladed

Pro-peller Models, Journ. of Zosen Kiokai Vol. 102, 1958.

243 Modified AUS-SO 0.250 0.180 0.800 0.364 0.050 1000' 5

6.346.61 x 10

LOOR

--q 5.0d\

r2.4Q..

3.60 Values

of J - K

Table 2

k O.60R _\

-

_____

\..:

_-j

' O.40R .

-\

i . .

I

L 0.20R

...

_

DIMENSIONS ARE SI0WN

AS PERCENTAGE OF D.

Fig. i General plan of modified AU 5-80 propeller model.

'N. 0.4 0.6 0.8 1.0 1.2 K, lO K5 fl0 K, 10 K0 1), K, loK5 1) K, loK) 1k K, lo1E k 0 0.1590 0.1310 0 0.2690 0.2730 0 0.3870 0.4760 0 0.4970 0.7230 0 0.6020 1.0140 0 0.05 0.10 0.1310 0.1230 0.1693 0.2390 0.2500 0.1520 0.3540 0.4420 0.1274 0.4615 0.6810 0.1078 0.56S0 0.9610 0.0935 0.15 0.20 0.1000 0.1070 0.2972 0.2040 0.2220 0.2922 0.3180 0.4040 0.2502 0.4235 0.6360 0.2118 0.5270 0.9070 0.1848 0.25 0.0825 0.0980 0.3351 0.1855 0.2065 0.3575 O.2985 0.3840 0.3094 0.4045 0.6120 0.2630 0.5090 0.8'80 0.2301 0.30 0.0630 0.0870 0.3460 0.1660 0.1900 0.4176 0.2770 0.3620 0.3658 0.3840 0.5860 0.3132 0.4890 0.3490 0.2753 0.35 0.0430 0.0760 0.3151 0.1445 0.1735 0.4639 0.2545 0.3385 0.4187 0.3630 0.5590 0.3617 0.4695 0.8190 0.3193 0.40 0.0210 0.0630 0.2123 0.1220 0.1550 0.5014 0.2315 0.3140 0.4696 0.3410 0.5310 0.4091 0.4490 0.7880 0.3630 0.45 -0.0005 0.0495 0.0955 0.1370 0.5200 0.2080 0.2895 0.5144 0.3175 0.5010 0.4537 0.4270 0.7560 0.4044 0.50 0.0760 0.1180 0.5126 0.1840 0.2650 0.5528 0.2940 0.4710 0.4969 0.4040 0.7240 0,4440 0.55 0.0510 0.0975 0.4577 0.1600 0.2390 0.5858 0.2705 i4410 0.5367 0.3795 0.6895 0.4821 0.80 0.0240 0.0780 0.3016 0.1365 0.2130 0.6120 0.2460 0.4100 0.5730 0.3545 0.6550 0.5168 0.65 -0.0010 0.0515 0.1130 0.1880 0.6220 0.2220 0.3790 0.6063 0.3295 0.6195 0.5505 0.70 0.0890 0.1620 0.6120 0.1980 0.3470 0.8360 0.3050 0.5830 0.5828 0.75 0.0620 0.1330 0.5566 0.1735 0.3145 0.6587 0.2800 0.5450 0.6135 0.80 0.0350 0.1040 0.4288 0.1495 0.2820 0.6754 0.2545 0.5050 0.6420 0.85 0.0070 0.0720 0.1315 0.1245 0.2490 0.6765 0.2295 0.4660 0.6663 0.90 -0.0220 0.0380 0.0980 0.2130 0.6592 0.2040 0.4260 0.6863 0.95 0.0710 0.1760 0.6100 0.1790 0.38i' 0 7011 1.00 0.0430 0.1350 0.5072 0.1540 0.3450 0 7106 1.05 0.0140 0,0955 0.2449 0.1290 0.3030 0.7114 1.10 -0.0140 0.0550 0.1035 0.2610 0 6944 1.15 0.0760 0.2170 0.6410 1.20 0.0470 0.1710 0.5249 1.25 0.0190 0.1245 0.3035 1.30 -0.0110 0.0730 244 TECNOLOGIA NAVAL

.2 o 08 07 06 0 - 05 04 03 02 0. o DIAGRAM

TYPE. MODIFIED AU 5-BLADED PROPELLER, CONSTANT PITCH

o' 0.7 .6 .5 4ç-, .3 .2 MODIFIEDAUS -80 CONSTANT PITCH BOSS RATI0Q, 180 0.050 RAKE AP4GLE-iO'O Ka EXPA.R.Oeoo ,1n,j/23rK B.T R. tI,. T/95.5.

iuiIIuiIu.

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VOL. I - N.° 3 - JULY/SEPTEMBER 1968 245 O 01 02 03 04 0.5 06 07 08 09 0 Il 2 3 14

Fig.2 J_KT,KQ,Ì?O Curves

Exp.A. R. 0.800 Boss Ratio 0.180 8.T.R. 0.050 flak.

Angie .Q'

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' n.., .'UL.UsS U5 Sa I4.ae ..%. IU.I4.IU .'ji,.'... :.

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Fig.3 f- Diagran (AU 5-80)

Lo N .9 08 7

r

o. .6

NAVAL HYDRODYNAMIC

PROBLEMS SOLVED

BY RHEOELECTRIC ANALOGIES

PROBLEMAS DE HIDRODINÁMICA NAVAL RESOLVIDOS ATRAVES DE CRITERIOS DE ANALOGIA REO-ELETRICA

por/by

L. MALAVARD ()

APRESENTAÇAO

Durante dez anos o Centro de Cálculo Analógico do Conseiho Nacional da Pesquisa Científica de Paris, na França, con-tribuiu corn vários trabalhos para o estudo e a soluçâo de urn sem-núrnero de problemas de Hidrodinámica Naval. Tal contribui. cáo deve Ser considerada muito significativa, pela relevância dos estudos realizados e pela influência exerckia na soluçào de pro-blemas fundamentals da Arquitetura Naval.

Tal importante contrlbuiçäo se tornou possível, entretanto, graças apenas a urna p e q u e n a equipe de pesquisadores de grande valor que, utilizando equipamentos de cálculo e de experimentaçäo bem simples, deu ao mundo urna sobeja demonstra-cáo do pêso das qualidades humanas, incluindo nelas a perfeita aplicaçâo de correta metodologia e mentalidade científica, na con-duçâo de pesquisas teorético-aplicadas.

Corn éste trabalho, todavia, o Professor Malavard, Ilustre catedrático da Universidade de Paris e Diretor do referido Cen-tro de Cálculo Analógico, conseguiu, a nosso ver, produzir a tese de major importância para a Arquitetura Naval, do referido time daquela instituiçâo, tendo merecido um significativo sucesso noSÉTIMO SIMPÓSIO INTERNACIONAL DE HIDRODINÁMICA NAVAL, recentemente realizado em Roma, na ltália, de 25 a 30 de agôsto próximo passado.

TECNOLOGIA NAVAL esta apresentando, portanto, um trabalho de grande valor, prâticarnente inédito.

I. - INTRODUCTION

For ten years the Centre de Calcul Analogique

(C.C.A.) of the Centre National de la Recherche

Sci-entifique has contributed by various works to the study

and to the solution of quite a large number of naval

hydrodynamic problems. This contribution may be

considered very significant since it has been made

possible by a small team of research scientists using

very simple computing equipment. This

equipment

could seem inadequate for the work to be done in the

eyes of the non initiated or of the

staunch believers

in computing on large computers.

However, it is not possible to consider these studies

of naval hydrodynamics completely isolated from a

context where rheoelectric analogy is the means which

has enabled, and still enables, important developments

in the most varied fields of Mathematical Physics.

And, in this connection, it is convenient to recall that

the

first studies carried out in France using the

electrical analogy techniques concerning some

hydro-dynamic problems; flows around bodies with or without

circulation, Oseen flows (1) * (2), flows with jet stream

lines

(3),

etc.;

premise

of a budding vocation;

a

vocation which became more decisive as from 1958

thanks to the experience acquired by the C.A.Ç. in

the treatment of problems in incompressible

aerodyna-mics, thin foils, lifting line, lifting surface, cascades,

simple helicoidal machines, etc.,

(4),

(5).

(6), and

thanks to the introduction by Tulin and Burkart (7)

in 1955 of the linearised theory of cavitations.

One of the assets which has assured the success

of rheoelectric analogy since its early beginnings has

been its rapidity, as well as its ability in solving

La-placien field equations. This capacity for computing,

Professor of the University of Paris (Chair of Aviation), Frunce

Diretor of the "Centre de Calcul Analogique" of the C.N.R.S., France

together with the experimental character of the

tech-nique employed, makes an ideal means for the practical

worker, engineer or physicist, who remains in contact

with a model on which his controlling action may

be

exercised without any restraint. Nevertheless, for an

intensive and complete use of the method, analog

simulation often requires turning to certain

methods

of theoretical formulation familiar to the

mathema-tician. It is in this way, for example, that the

know-ledge of elementary analytical solutions, the use

of

conformal mappind, the analysis of singularities,

etc.,

allow the solution of each problem in the most efficient

way

From these three given elements cited, experience

acquired in incompressible aerodynamics, the

ilneari-sed theory of cavitations and auxiliary analytical data,

naval hydrodynamic studies have been developed as

follows.

1.1. TWO-DIMENSIONAL PROBLEMS (fig. i;

In 1958, Luu carried out studies on the solution of

the direct problems of supercavitating hydrofoils (8),

(9). These studies were the continuation of important

research devoted to the problem of thin jet streams

in aerodynamics (8), (10), (11), (12) and came within

the framework of linearised free boundaries.

In

1960

a: research programme was envisaged

concerning the effects of the free surface on slightly

immersed sub and supercavitating hydrofoils. In the

case of small Froude numbers, that is to say a

consi-derable influence of the gravity field effect, is was

possible to proceed easily to their design for imposed

pressure distribution (inverse problem) (13) (14). These

studies took into account the gravity effect on the

free surface and on the finite cavity, which, to our

knowledge, had not

yet been treated. The direct

246