Cavitation tests of the 3-blade Kamewa controllable pitch propeller

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LIMITED COPY NO.

NATIONAL RESEARCH COUNCIL OF CANADA

MECHANICAL ENGINEERING REPORT MB-221

CAVITATION TESTS OF THE 3- BLADE KAMEWA

CONTROLLABLE PITCH PROPELLER

BY

J. S. C. STRASZAK

DIVISION OF MECHANICAL ENGINEERING

OTTAWA

14 DECEMBER 1959

THIS REPORT MAY NOT SE PUBLISHES N WHOLE OR

IN PART WITHOUT THE WRITTEN CONSENT OF

Submitted by:

Approved by: D. C. MacPhall Director

SUMMARY

This report contains the results of cavitation tests carried out on the 3-blade KaMeWa controllable pitch propeller at the pitch ratios of 0.4, 0. 6, 0. 8,

0.98, 1. 17 and 1.52. Curves of KT, KQ and for a number of cavitation Indices and the cavitation inception diagrams for a wide range of speed of advance coefficients have been obtained at each of the above pitch settings. Photographs of the cavitating propeller at selected pitch ratios are included.

NATIONAL RESEARCH LABORATORIES

Ottawa, Canada

RE PORT

Division of Mechanical Engineering Ship Laboratory

LIMITED

Pages - Preface -

3 Report: MB-221

Text - 3 Date: 14 December 1959

Figures 15 Lab. Order: 13435A

File: M2-3-7

For: Internal

Subject: CAVITATION TESTS OF THE 3-BLADE KAMEWA

CONTROLLABLE PITCH PROPELLER

Prepared by: J.S.C. Straszak

S. T. Mathews Head Ship Laboratory E.S. Turner Head Hydrodynamics Section

K=

pND

V ND KTJ 21rKQ Po _{- Pv} 2 pV °c V 1 (0.775 - 2 F. C. B.C. E.H.V. E.T.V. LIST OF SYMBOLS Symbol Definition D Propeller diameter

P/D Propeller pitch ratio at 0. 7 radius of the blade

V Propeller speed of advance (corrected for wall effect)

N Shaft rotary speed, rev. /urút time

Q Shaft torque

T Propeller thrust

p Water density

Po Ambient pressure at the centre of propeller shaft

Water vapour pressure at standard temperature

KT = 4 Non-dimensional propeller thrust coefficient

pND

Non-dimensional propeller torque coefficient

Non-dimensional propeller speed of advance coefficient (corrected for wall effect)

Propeller open water efficiency

Cavitation number based on the speed of advance

Cavitation number based on the resultant speed of advance at 0. 7 radius of propeller

Face cavitation Back cavitation

Established hub vortex Established tip vortex

Page - (iii)

INTRODUCTION

The model propeller, subject of_{the present report, was tested in the}

cavitation tunnel of the Ship Laboratory, National Research Council, _{as a part of}

an internal programme to provide information _{on the cavitation performance of}

the controllable pitch propellers.

MODEL AND ITS ADAPTATION _{TO N. R. C. TUNNEL}

The brass propeller model, 245 mm. in diameter, _{was provided by the}

designers, KaMeWa of Sweden. _{The model consisted of three}

No. 333-B blades

and the propeller boss stamped _296-B.

Due to the opposite directions of _{flow in the KaMeWa and the N. R. C.}

tunnels, some modifications to the propeller boss, and the _{manufacture of new}

forward and after fairing_{pieces, were necessary. Instead of altering the propeller}

boss supplied by KaMeWa, _{a new one was made. Forward and after fairing pieces} were made in accordance with the following _{KaMeWa drawings:}

336248 - model propeller hub

360831 - proposed _{cone cover}

The blades, slightly damaged_{in transit, were repaired prior to}

com-mencing the experiments. Pitch ratio settings quoted refer to the pitch ratio at

0.7 radius. Measurements of _{pitch distribution over the blade were carried out}

at the P/D _{0.98 setting (basic design setting) and show fairly good}

agreement with the pitch distribution curve provided by KaMeWa.

The true expanded section _{particulars of the blade were given in the}

KaMeWa Drawing No. 357517 _{- "KaMeWa Navy Propeller" and are reproduced}

for the model in Figure 1. _{The propeller model form plan is appended}

as Figure 2.

MODEL PITCH SETTINGS

Different values of pitch ratio required for experiments were set In accordance with the KaMeWa _{diagram No. 4426, "Data for Pitch Setting", where}

they were available, but separate calculations for the pitch _{ratios of 0. 4 and 0. 6}

were made as no KaMeWa figures for _{these pitch ratios were quoted.}

Page - i

MB-221 CAVITATION TESTS OF THE 3-BLADE KAMEWA

patterns occurring at the following selected conditions:

Positions of A, B and C, at which the above photographs were taken, are also shown on the cavitation inception curves for the corresponding pitch

ratios of 1.52, 0.98 and 0.4 in Figures 12, 10 and?, respectively.

¡LE S Page - 3 MB-221 Photograph A B C P/D 1.52 0.98 0.4 J 1.1 0.65 0.3

°cv

1.75 3.0 35.0 V ft. /8cc. 15 15 5

N r.p.m.

1017.9 1722.6 1244.1

b

DISTANCE d = 20 mm.

PROP. RAD. R r 22.5 mm.

O.7R r 85.75 mm. USED FOR PITCH SETTING

CENTRAL ANGLE Q 4O°

b r * 0.7 X 2iTR r 59.53mm.

PITCH RATIO AT O.7R, P/Do7 0,4 0.6 0.8 0.98 1.17 .52

P/O0 7/lr x 0.7 : TAN 0.1819 0.2728 0.3640 0.4456 0.5323 0.6912 ìfr _{lO°19' 15° 16' 20°0O'} 24° 01' 28°0I' 34° 39 SIN 0.1791 02633 0.3420 04070 0.4700 0.5685 COS _{0.9838 0.9653 0.9397 0.91 36 0.8830 0.8236} BAC K

PITCH SETTING TABLE

Table

I

MB-22 I

C _b/COS 60.82 _{61.98 63.67 65.49 67.76 72.64}

a b/TAN 10.88 6.32 21.77 26.66 31.85 41.35

0025" 0027" +0002 o4e 0060" 005 0027" 0016 (06" .OI2" 4Z" QpV -0002" ooeoJ 0.024" 0036" 0.021" 0 0024" .022" P006" -0.001" w 04 0.054" (QQ" 0128" 0124 0112" 0.085" 0075" -0.006" 0.034" 0054" 0.031" 0026" w w 'D p-o o AFfliCULARS N FIG. I MB-221 00I" 0.100" 0.018" 1113" p.006" Oils" .0.027" Q075 0.020" 0060" 0.023" 0125" 0.032" .0lI.

ABLE PITCH PROPELLER. MODEL PARTICULARS D MEASURED FOR NOMINAL P/D07 : O.98 FIG. 2 MB-221 MEASURED P/D DISTRIBUTION . PROFILE , (FOR NOMINAL P/Do.? 0.98) 0.820 x RADIUS MAX. TH ICKNESS LOO 4.823

-0.871 0.95 4.582 0.06. 0918 0.90 4.341 0.082 ' 0.976 0.80 3858 0.128 0.994 0.70 3.376 0.174 1.015 060 2.894 0219 1.010 . 0.50 2.411 0.265 -

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KAMEWA CONTROLL (DRAWN AN DRO. NO. 22081 DIAMETER D 9.646 IN. EXPANDED AREA AE 50.49 IN.2 PITCH AT O.7R P0.7 9.590 IN. PROJECTED AREA Ap 43.81 INt PITCH AT TIP T 7.910 IN. EXPANDED AREA RATIO AE/AO : 0.69 PITCH AT BOSS B 8.431 IN PROJECTED AREA RATIO Ap/A0 = 0.60 NO. 0F BLADES Z 3 BOSS DIA. RATIO d/D 0.286 EXPANDED BLADE PROJECTED BLADE

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