MAR2010 - Standard Series Data

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Rod Sampson - School of Marine Science and Technology - 21st February 2008

...Open water propeller tests, Standardseries model propeller tests and Propeller

design diagrams...

Resistance & Propulsion (1)

MAR 2010




Open water propeller test

O/W tests performed with the propeller alone inuniform flow to establish:

Basic thrust, torque and propeller efficiency




Open water propeller test

Two facilities are commonly used to perform openwater tests:

Towing tank

Cavitation tunnel

Each facility has its own limitations




Open water test - propeller boat

Towing carriageshaft bearing

clearancespropeller boat

boss cap




Open water test - cavitation tunnel

Flow direction

shaft bearing

propellerdynamometer

boss cap




Open water test - concept

flow direction

Full scale vessel

boss cap





flow direction



Undisturbed flow



boss cap

Dflow

not less than 1.5D

towing carriage Velocity

• Lenticular shaped “propeller boat” mounted on the towing carriage

• Boat advances through undisturbed flow

• Velocity and shaft rpm are varied





drive motordynamometer

PROFILE

PLAN

not less than 1.5D





• measurements taken over a series of runs

• Thrust & Torque are taken at varying J (n usually kept constant)

• Velocity varied from zero speed ( J = 0) to higher values withinthe limitation of the system ( J = 1.0)

note: J = 1.0 is not an upper limit

Tests are performed usually until KT tends to zero




Open water test - results

J =V

nD

C T =

T

ρV 2D2

Test results are presented in the earlier derived coefficients:

C Q =

Q

ρV 2D3





As CT and CQ 0 as V = 0

CT and CQ are replaced by Aeronautical coefficients

KT and KQ respectively

using:

V = n2D

2





C T =

T

ρV 2D2 K T =

T

ρn2D4

C Q =

Q

ρV 2D3 K Q =

Q

ρn2D5





η0 =P T

P D=

TV

Q2πn

η0 =J

2π×

K T

K Q



0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.1 0.2 0.3 0.4 0.5 0.6 0.65 0.7 0.8

KT 10 KQ Eta_0

Advance coefficient

Basic Design - open water tests




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.1 0.2 0.3 0.4 0.5 0.6 0.65 0.7 0.8

KT 10 KQ Eta_0

Advance coefficient

Basic Design - open water tests

φV

2πrn

Thrust

Torque

Vr

φ

V

2πrn

Thrust

Torque

Vr

D

L

D

L

L


Small V ( J ) = Large T Large V ( J ) = Small T



Standard series Propeller model test

Tests form the basis for propeller design

Parameters that influence the performance aresystematically varied in the parent design





Diameter (D)Pitch (P)

Blade area ratio (BAR)Number of blades (Z)

Blade shapeBlade thickness

Usually D is fixed, P/D varied

BAR & Z are varied

Kept constant in line with goodmodern design practice

Rod Sampson - School of Marine Science and Technology - 26th February 2008




Vary P/D

Vary Z

Vary BARParent model P/D

BARZ

3,4,5,6 blades = 4 models

0.4 - 2.0 by 0.2 = 9 models

0.4 - 1.5 by 0.15 = 6 models

216 members









From the Parent model a series of 216

propeller models would be generated.

Each member requires testing in open waterconditions

The data from each test is combined intodesign diagrams with varying P/D and fixedBAR & Z





P/D = 0.4 P/D = 0.8 P/D = 1.0P/D = 0.6

L ine o f m a x imum e f fic ienc y

K T P / D = 1 .0

1 0 K Q P / D = 1 .0

η0

1 0 K Q P / D = 0 .4 K T P / D = 0 .4

Find optimum diameter to absorb:

a delivered power (kW)

a shaft rotation (N)

an advance speed (VA)


J





Using the above diagram design an propeller(optimum diameter)to absorb:

• Delivered Power Pd (kW)

• Rotation N (rpm)• Advance speed J (kn)




First obtain:

n =N

60

Q = 1000P D

2πn

N.m


S




Then:

K Q =

Q

ρn2D5 =

k1

D5

J =V A

nD =

k2

D


S d d P ll d l




P/D = 0.4 P/D = 0.8 P/D = 1.0P/D = 0.6


K T P / D = 1 .0

1 0 K Q P / D = 1 .0

η0

1 0 K Q P / D = 0 .4 K T P / D = 0 .4

Plot 10KQ and J for varying D on the diagram

Intersect with line of maximum efficiency ( )η0


S d d P ll d l




P/D = 0.4 P/D = 0.8 P/D = 1.0P/D = 0.6


K T P / D = 1 .0

1 0 K Q P / D = 1 .0

η0

1 0 K Q P / D = 0 .4 K T P / D = 0 .4

Read off J, hence: Dopt =k2

J

advance coefficient

Interpolate P/D


P ll D i Di



Given data required data

1.2.

3.

4.5.

6.

Propeller Design Diagrams

The representation of systematic open water

diagrams may differ depending upon various designoptions which can be listed as:

P D,N ,V AP D,D,V AP D, V A

T,N,V AT,D,V AT, V A

Dopt

N opt

N opt, Dopt

Dopt

N opt

N opt, Dopt


P ll D i Di





From the previous options the most widely usedcase is option 1 & 4.

Option 1 requires the delivered power and

rotation rate to be known at a specified advancevelocity

The unknown variable is the optimum propeller

diameter

P ll D i Di





Considering option 1:

The diameter can be eliminated from the systematicopen water diagrams by replacing the and J

terms as follows:

K Q

K Q vs 1

J

P D,N ,V A D

opt

K Q

J 5 =

Q

ρN 2D5 ×

1V anD

5 =

QN 3

ρV 5a

P ll D i Di





Since:

P D = 2π

QN

K Q

J

5 =

N 2P D

2πρV

5 −→

NP 1

2

D

V

2.5

A

K QJ 5

= QN 3

ρV 5a

P ll D i Di





Let:B p =

NP 12

D

V 2.5A

andδ =

1

J =

ND

V A

P ll D i Di





Considering option 4:

A similar analogy can be used by replacing thestandard KT versus J by:

K T

J

4 =

T

ρN

2

D

4 ×

1

V a

nD4

=TN

2

ρV

4

a

P ll D i Di





Since PT = Va T ( PT = thrust power )

K T

J 4 =

P T N 2

ρV 5a

−→

NP 1

2

T

V 5a

= BU

Let

BU =

NU 1

2

V 5a

Where U = PT after useful power

P ll D i Di





(BP , BU & δ )The above coefficients

are known as the D.W. Taylors propeller constants,

most standard series propeller design diagrams aregiven using these constants.

Pr eller Desi n Dia rams





BP =

NP 1

2

DV 2.5A

= 1.158

NP 1

2

DV 2.5A

BU =NU

1

2

V 2.5A

= 1.158NU

1

2

V 2.5A

δ =ND

V A= 3.2808

ND

V A

η0 =P T

P D






Typical diagramBP − δ

Basic Design - BP delta diagrams





η0

δ

η0(max)

Line of max.

efficiency

BP Design

P D

BP






η0

δ

η0(max)

Line of max.

BP Desi

P D

BP

Calculate BPEnter diagramRead off at max efficiency line

BP − δ

δ opt.

Dopt. = V aδ opt

N −→ read P/D

Existing standard propeller series





Several key systematic series exist, developed forfixed pitch, controllable pitch propellers, ductedpropellers, etc.

FroudeSchaffranTaylorGawn

WageningenGawn-Burrill (KCA Series)KCn Series











One of the most extensive and widely used seriesis the Wageningen B series.

Fixed pitch propeller

Merchant ship style designSlow to medium speed operation

Wageningen B-Series



Wageningen B Series


Modern sections Good performance 210 members

Wageningen B-Series Characteristics




Wageningen B Series Characteristics






• Constant radial pitch distribution

• Small skew

• 15 degrees of backward rake angle

• blade contour with fairly wide tips

• segmental tip blade sections and aerofoil innerradial sections






B 4. 85

series type = B

blade number = 4

expanded area ratio = 0.85





Wageningen B Series analysed and presented as

polynomial equations

Allows computerisation of the design algorithm

K T =47n=1

C n (J )sn

P

D

tnAe

Ao

un

(Z )vn

K Q =47n=1

C n (J )snP

D

tnAe

Ao

un

(Z )vn

Documents

MAR2010 - Standard Series Data