Wake Adapted Propeller Design
Wake Adapted Propeller Design
Wake Adapted Propeller Design
*
Corresponding author. E-mail address: zaniso@163.com (Kang Han)
National Natural Science Foundation of China (51679052), National Defense Basic Research Project Funding Project
(JCKY2016604B001).
propeller design under open-water conditions are START
gradually exposed, and wake-adapted propeller design
methods become the mainstream idea. To achieve the
purpose of customized propeller design and parameter Initialize the Particle Swarm
optimization, the design process should contain these
procedures as follows: Calculating the Target Value of Each
1) Initialization theory wake-adapted design of the Particle
propeller: According to ship type characteristics and
design requirements, determine the input parameters of Update the Speed and Position of Each
the lifting line program, including propeller rotation Particle
speed, diameter, thrust, horsepower received by the
propeller and wake fraction et al. Among them, the wake Update Individual Optimal Position
fraction can be estimated based on the characteristics of Values and Global Optimal Positions
the ship and the experienced formula. Then, carry out the
propeller design process that does not consider the
influence of skew and rake distribution. Whether the Convergence
Condition Is Met NO
2) According to the principle of selection of rake and
skew, combined with initialization pitch angle, resonance YES
analysis the wake and choose reasonable rake and skew END
distribution. Fig. 2 Propeller wake-adapted optimization design process
3) Wake-adapted propeller design: Carry out lifting line 3 PARAMETERIZED MODLE OF THE PROPELLER
and lifting surface design process with the influence of The B-spline curve is flexible for curve control (LAXMI
rake and skew. Then, take advantage of hydrodynamic PARI DA 1993). If the geometric parameters of the
performances forecasting program to predict the paddle are parameterized based on the B-spline curve,
performance of the propeller and estimate whether the smooth geometric parameter distributions in the radial
propeller satisfied the instruction, otherwise, redesign the direction can be obtained with fewer control points. The
wake-adapted propeller. specific expression of the B-spline curve of the radial
4) Optimized design of wake-adapted propeller: This step distribution of the propeller geometry is as follows:
is to improve the performance of some aspects of the n
propeller further. Take the theoretical design paddle as the pu d i N i ,k u 0 u 1 (1)
parent type, and explore the range of variation of the i 0
design variables. Then, optimization program, iSIGHT
software and unsteady panel method program are used to Where p u is the geometric parameter distribution;
di i 1, , n are the control vertices of the curve
optimize the parameters of the propeller.
0.2 1.2
is the dimensionless radius, and this is also applicable to
B/D
OriginalPropeller
P/D
Original Propeller
B-spline 1.1
B-spline
the following.
0.1
1.0
0.0 0.9
0.8
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0
r/R r/R
1.0 330 30 0.000
0.1078
(a) Chord length ratio (b) Pitch ratio 0.8 0.2155
0.3232
40
0.12 0.6 300 60 0.4310
0.5387
0.10 30 0.4
0.6465
0.08 Original Propeller
B-spline 0.7542
20
0.2
0.06 0.8620
S(°)
Ra/D
0.04
0.0 270 90
10
0.6
Propeller Diameter
KT,10KQ
J Delivered Power
Thrust T(N) 66016.23 353.66
PD(kw)
Fig. 4 Comparison of the open-water performance curves of the
original paddle and the parameterized expression paddle Table 2 The circumferential average of the axial flow of the
HSP paddle
Given the advantages of the B-spline curve, four control
points are selected in this paper. The specific location of r/R 0.2 0.3 0.4 0.5 0.6
the four control points depends on the distribution of the Axial Flow 0.4568 0.3471 0.2697 0.2192 0.1899
geometric parameters. As shown in Fig. 3, the chord
length, pitch, thickness, camber, rake, and skew of the r/R 0.7 0.8 0.9 1
parameterized paddle are consistent with the original data. Axial Flow 0.1761 0.1722 0.1726 0.1717
The hydrodynamic performance of the paddle after the
3.2 The Selection of Skew and Rake Distribution
parameterized expression is calculated and compared to
Since the wake flow fields of different ships are different,
the hydrodynamic performance of the original paddle. As
it is necessary to select the appropriate skew distribution
shown in Figure 4, the open water performance curves are
according to the specific wake of ships. Before the
basically consistent between these two propellers. It can
theoretical design process, the harmonic analysis method
be seen that the inverse B-spline parameterized
is used to analyze the normal wake of the ship, and the
skew distribution is rationally selected to avoid the step force of the main blade can be obtained. It can be
various sections of the propeller rotating to the high flow seen from Fig. 6 that the main pulsation amplitude of the
velocity area simultaneously. And the skew distribution HSP propeller corresponding to the balanced and rear
must be considered together with the harmonic skew distribution is smaller than that of the original
components of the accompanying flow field, regardless of propeller and the balanced reduction is larger. Besides,
the radial accompanying flow, and the normal the average thrust coefficient of the main blade of the rear
accompanying flow for each profile is: skew HSP paddle (the thrust amplitude of the 0th order) is
wN wx cos p w sin p (4) larger than that of the original paddle, while the balanced
HSP paddle has reverse performance. However, the
Where wN = normal accompanying flow; wx = axial magnitude of the reduction is not large. Therefore, in
accompanying flow; wθ = circumferential accompanying order to ensure the strength characteristics, under the
flow; and βp = pitch angle. condition of satisfying the thrust of the propeller, the
Before the theoretical design process, it is necessary to balanced skew distribution form should be selected as
initialize the designed propeller and obtain the pitch angle much as possible. If the strength of the paddle is
to carry out the resonance analysis of the normal guaranteed, in order to improve the thrust coefficient of
accompanying flow field. This step is omitted because the the propeller the rear skew distribution can be selected.
geometric pitch angle of the original HSP paddle is
known. Through the resonance analysis, the maximum
normal phase angle of the 5th order is obtained as shown
in Table 3. Table 3 also shows the original skew
distribution of the original HSP paddle. The design
principle of the skew distribution is that the skew
distribution curve should have a relatively large
intersection angle with the normal accompanying flow
phase distribution curve. According to this principle, the
authors initially selected two modes of HSP propellers in
the form of balanced and rear skew forms along with the
radial distribution. Fig. 6 The amplitude of the thrust coefficient of the main blade
Table 3 The maximum normal phase and three kinds of the of three propellers of a rotation
lateral distribution of flow field in HSP impellers The main purpose of the rake distribution is to increase
Maximum the distance between the blade and the hull and reduce the
Skew of washing effect to the hull, and thus the vibration could be
normal Balanced Rear Skew
Original
r/R Distribution Distribution reduced, however, the designers usually design the
phase angle propeller
(°)
(°) (°) propeller in isolation and consider the wake of the hull to
(°) account for the effect of the speed field on the propeller
0.1 -37.38 0 0 0 after the hull. The rake distribution patterns include the
972 blade inner radius front and outer radius rear distribution,
0.2 -36.6 -0.21 -0.32 0.01
the front rake and the rear rake. From the perspective of
0.3 -13.02 -3.93 -7.82 1.18 strength, the rear rake should not be too large to reduce
0.4 2.83 -2.94 -8.61 3.82 the centrifugal force bending moment; and the front rake
is beneficial to the strength of the large skew propeller
0.5 10.94 -0.06 -4.22 7.76
and can effectively reduce the stress level of the paddle.
0.6 6.77 4.31 3.8 12.85 From the perspective of hydrodynamic performance, the
0.7 3.94 11.1 13.94 18.94 thrust coefficient and torque coefficient of rear rake
propeller will increase with the increase of the rake angle,
0.8 3.48 20.06 24.64 25.86
and the front rake can improve the efficiency of the
0.9 2.29 30.45 34.38 33.48 propeller. From the perspective of the cavitation, the rear
0.9 1.43 35.97 38.41 37.49 rake can improve the three-dimensional flow of the tip,
5 thereby delaying the initiation of the tip vortex.
0.9 0.92 38.78 40.13 39.54
75 Considering the hydrodynamic performance, cavitation,
1 0.38 41.62 41.62 41.62
noise, and strength of the propeller, the rake distribution
Under the condition of other geometric parameters that inner radius front and outer radius rear can be
keeping accordant, the unsteady hydrodynamic selected.
performance of different HSP propellers was predicted,
including original skew, balanced and rear skew versions. In this example, the HSP paddle selects the five-blade in
Based on the Fourier analysis method, the unsteady thrust the redesigned process. The rake and skew distribution
coefficient of the main blade of the HSP paddle in three options are shown in Table 4 as the input parameters for
skew modes can be analyzed, and the amplitude of each the lifting line program.
3.3 Theoretical Design Result Table 6 Comparison of hydrodynamic performance between
After the selection of the rake and skew, the wake- original HSP propeller and designed propeller
adapted theory design of the HSP paddle can be carried
out. Table 5 shows the geometric parameters of the KT KQ
designed propeller, where B/D is chord length ratio; P/D Original Propeller 0.172 0.02687
is pitch ratio; T/D is thickness ratio, and f/B is camber Designed Propeller 0.168 0.0261
chord length ratio. The pitch of the blade root and blade
Error 2.33% 2.87%
tip is smaller than that of the original paddle, which is
beneficial to reduce the hub vortex and tip vortex of the
propeller.
0.10
Designed Propeller KT
Figure 7 shows a three-dimensional model of the Designed Propeller 10KQ
propeller with a smoother geometry. The stress 0.08
Original Propeller KT
distribution prediction of the designed propeller is based Original Propeller 10KQ
on the program developed by the laboratory using panel 0.06
method and the cantilever beam method, as shown in Fig.
Kt,10Kq
8. The maximum stress value of the paddle is 2.5*107 Pa
0.04
(255.1 kgf/cm2), which is less than the allowable stress of
the material of 637kgf/cm2, and the strength meets the
0.02
requirements.
Table 5 Geometric parameters of the designed propeller 0.00
0 60 120 180 240 300 360
0
r/R B/D P/D T/D f/B ( )
0.2 0.173 0.708
Oj 0.037 -
0.3 8
0.208 RRRr
0.925 8
0.032 0.0074
0.0175 Fig. 9 The thrust coefficient and torque coefficient of the
0.4 2
0.241 9
1.036 2
0.025 0.0253 original HSP propeller and the design master blade
0.5 9
0.272 2
1.069 0.017 0.0291
0.6 7
0.295 1.014 8
0.013 0.029
0.7 5
0.303 7
0.889 4
0.011 0.0258
0.8 1
0.292 6
0.754 2
0.009 0.0202
0.9 4
0.237 9
0.637 4
0.007 0.0095
0.95 0.163 3
0.578 8
0.007 0.0047
1 90 1
0.510 0.006 0
8
7
6
-2E+07
0
-
-
2.5E+0
5E+0
7
6
-3E+07
-
Y
3.5E+07
3E+07
X
3E+07
0.26
of propeller 1 and propeller 2 are both lower than that of
0.24 original HSP propeller while the average thrust
coefficients are higher. Therefore, the rapidity and
0.22 vibration performance of the propeller 1 and the propeller
2 are better than those of the original HSP in the wake of
0.20
the ship.
0.18 Table 7 Comparison of Hydrodynamic Performance
0.16 The amplitude of Average thrust
thrust of the main coefficient
0.0124 0.0128 0.0132 0.0136 0.0140 0.0144 blade
the 2ed Amplitude of Thrust of the Main Blade Original Propeller 0.01408 0.172
Theoretical Propeller 0.1287 0.168
Fig. 11 Propeller Proper Flow Optimization Design
Propeller Pareto Frontier Propeller 1 0.01292 0.2362
Select two suitable optimization scheme from the Pareto Propeller 2 0.01239 0.229
Graph to analysis, starting now referred to as the propeller
1 and propeller 2. Figures 12 and 13 show the stress
prediction results for the two options. The maximum
stress of the propeller 1 is 3.5*107Pa (357.1 kgf/cm2), and
the maximum stress of the propeller 2 is 3*107 Pa (306.1
kgf). /cm2). It can be seen that the maximum stress of the
two schemes does not exceed 637kgf/cm2, and the
strength meets the requirements.
0.30
1.2 whole blade is unfavorable in such condition. The camber
0.25
1.0 at the blade root of these three propellers is much smaller
0.20
P/D
than that of the original HSP paddle, which is
B/D
0.8
0.15 Original HSP Propeller
Theoretical Designed peopeller Original HSP Propeller
0.10
0.05
Propeller 1
Propeller 2 0.6
Theoretical Designed Propeller
Propeller 1
Propeller 2
advantageous for the strength and the hub vortex at the
0.00
0.4 blade root; the camber distribution in the middle of the
-0.05
0.2 0.3 0.4 0.5 0.6
r/R
0.7 0.8 0.9 1.0 0.2 0.3 0.4 0.5 0.6
r/R
0.7 0.8 0.9 1.0
blades of two optimized propellers is larger than that of
the theoretically designed propeller which is useful for
(a) Chord length ratio (b) Pitch ratio improving the thrust of the propeller. The trend of the
0.06
50 skew distribution of all these four propellers are similar,
0.05
0.04
40
but these three propellers have larger skew at the blade tip
30 Original HSP Propeller
0.03
20
Theoretical Designed Propeller
Propeller 1
Propeller 2
than that of the original HSP paddle. This is advantageous
0.02
for reducing the unsteady thrust amplitude of the largest
S(°)
f/B
10
0.01
0.00
Original HSP Propeller
Theoretical Designed Propeller
Propeller 1
0 main blade. For rake, the rake of the blade root of the
-0.01
Propeller 2 -10
optimized paddles is reduced, and the rake near the blade
-0.02 -20
0.2 0.3 0.4 0.5 0.6
r/R
0.7 0.8 0.9 1.0 0.2 0.3 0.4 0.5 0.6
r/R
0.7 0.8 0.9 1.0
tip is increased. Actually, the rake distribution of these
three propellers is quite different from the original paddle,
(c)Camber ratio (d) Skew and this form of distribution is advantageous for the
0.06
strength of the propeller.
Original HSP Propeller 5 CONCLUSIONS
0.04 Theoretical Designed Propeller
Propeller 1 In this paper, the resonance analysis method of the flow
Propeller 2
field, the selection method of the number of blades, skew
0.02
and rake distribution, lifting line and lifting surface
Ra/D