Numerical investigation of the rake angle effect on the hydrodynamic performance of propeller in a uniform and nonuniform flow

Author(s):  
Hasan Sajedi ◽  
Miralam Mahdi

Marine propeller always operates in the wake of a vehicle (ship, torpedo, submarine) but (due to the high computational cost of simulating vehicle and propeller simultaneously) to investigate the propeller geometric parameters, simulations are usually performed in open-water conditions. In this article, using the computational fluid dynamics method with the control volume approach, the effect of the rake angle on the propeller performance and formation of cavitation in the uniform flow (open water) and the nonuniform flow (wake flow) was investigated. In the nonuniform condition, the array of plates was used to simulate wake at upstream propeller. For uniform flow, steady solution scheme was adopted and for nonuniform flow unsteady solution scheme was adopted, and a moving mesh zone was generated around the propeller. To simulate cavitation a multiphase mixture flow, the Reynolds-averaged Navier–Stokes method was used and modeled by Schnerr Sauer's cavitation model. First, the E779a propeller model for numerical validation in the uniform flow and nonuniform flow was investigated. Numerical results were compared with the experimental result, and there was a good agreement between volume of the cavity, thrust, and torque coefficients. To study the effect of rake angle on the performance of B-series propellers, four models with different rake angles were modeled, and simulation was investigated behind the wake. The results of thrust, torque coefficients, and cavitation volume according to the flow parameters and cavitation number were presented as graphs. The results reveals that in the uniform flow, the rake angle has no significant effect on the propeller performance, but behind the wake flow, increase of rake causes to reduce the force applied to the propeller blades, cavitation volume, and pressure fluctuations on the propeller.

2020 ◽  
Vol 27 (4) ◽  
pp. 50-59
Author(s):  
Alireza Nadery ◽  
Hassan Ghassemi

AbstractThe presented paper numerically carries out the investigation of the hydrodynamic performance of the propeller behind the ship with and without wake equalizing duct (WED). It is mounted in front of the propeller in order to equalize the ship’s wake flow and improve the propeller performance. The computational fluid dynamics (CFD) analysis software STAR-CCM solver was adopted to simulate the KP505 propeller behind the KRISO container ship (KCS) using overlapping grid technology and user-defined functions. To obtain the effect of a –duct on propeller performance, the ship bare hull case, the with-propeller case, and the with-propeller-and-duct case are also computed. Together, these computations provide for a –complete CFD comparison of the duct effects. Also, the Taguchi design of the experiment method is applied to investigate three parameters (angle of attack, trailing edge radius, and chord length) of the duct. Finally, the main dimensions are obtained, and the thrust and torque coefficients are presented and discussed for one blade and whole blades during one cycle. Based on the numerical results, it is indicated that good design increases efficiency by 1.67%, and a –bad design may reduce efficiency by 3.25%. Also, the effect of the WED caused to decrease the pressure pulse by 35.9% in the face side of the propeller blade.


1994 ◽  
Vol 116 (3) ◽  
pp. 185-189 ◽  
Author(s):  
D. Walker ◽  
N. Bose ◽  
H. Yamaguchi

Experiments were done on a 200-mm-dia open propeller behind a simulated ice blockage in a cavitation tunnel. The propeller performance in uniform flow and blocked flow is contrasted over a range of advance coefficients and at different cavitation numbers. Mean thrust and torque coefficients are presented. The types of cavitation, and its intermittent nature over a cycle of operation, are reported. The experiments indicate the likelihood of cavitation at full scale for blocked conditions and illustrate the effects of cavitation on mean values of thrust and torque.


1989 ◽  
Vol 26 (03) ◽  
pp. 192-201 ◽  
Author(s):  
Neil Bose ◽  
Peter S. K. Lai

Open-water experiments were done on a model of a cycloidal-type propeller with a trochoidal blade motion. This propeller had three blades with an aspect ratio of 10. These experiments included the measurement of thrust and torque of the propeller over a range of advance ratios. Tests were done for forward and reverse operation, and at zero speed (the bollard pull condition). Results from these tests are presented and compared with: a multiple stream-tube theoretical prediction of the performance of the propeller; and a prediction of the performance of a single blade of the propeller, oscillating in heave and pitch, using unsteady small-amplitude hydrofoil theory with corrections for finite amplitude motion, finite span, and frictional drag. At present, neither of these theories gives a completely accurate prediction of propeller performance over the whole range of advance ratios, but a combination of these approaches, with an allowance for dynamic stall of the blades, should lead to a reliable simple theory for overall performance prediction. Application of a propeller of this type to a small ship is discussed. The aim of the design is to produce a lightly loaded propeller with a high efficiency of propulsion.


2013 ◽  
Vol 437 ◽  
pp. 32-35
Author(s):  
Li Jian Ou ◽  
Nan Huo Wu ◽  
De Yu Li

Firstly, the calculated model was created in UG and GAMBIT, and then the Moving Mesh method was adopted to simulate thrust and torque of ducted propeller using FLUENT in the open water. The thrust, torque and bearing force of ducted propeller in three different wake fields were calculated. And the influence on the performance of ducted propeller by the wake fields was analyzed.


2019 ◽  
Vol 2 (2) ◽  
pp. 185-193
Author(s):  
Nur Amira Adam ◽  
Ahmad Fitriadhy ◽  
W. S. Kong ◽  
Faisal Mahmuddin ◽  
C. J. Quah

A reliable prediction approach to obtain a sufficient thrust and torque to propel the ship at desired forward speed is obviously required. To achieve this objective, the authors propose to predict the thrust coefficient (KT), torque coefficient (KQ) and efficiency (η) of the propeller in open-water model test condition using Computational Fluid Dynamics (CFD) simulation approach. The computational simulation presented in the various number of rotational speed (RPM) within the range of advance ratio J=0.1 up to 1.05. The higher value of J lead to decrease 10KQ and KT. While the η increased steadily at the lower value of J and decreased at the higher value of J. The results also showed that the propeller with 1048 rpm obtain a better efficiency at J=0.95 with η= 88.25%, 10KQ=0.1654 and KT= 0.0942. The computation result is very useful as preliminary data for propeller performance characteristics.


2010 ◽  
Vol 143-144 ◽  
pp. 1143-1147
Author(s):  
Bing Xiao ◽  
Xiao Wang ◽  
Ai Guo Shi ◽  
Ming Wu

In order to obtain the four quadrants hydrodynamic performance of open water propeller by means of CFD, a mathematic model of three dimensional coordinates points was established and programmed using Matlab based on the basic parameters of propeller. A smooth model propeller was made by importing these points into front end software. Then taking AU model for example, numerical simulations of propeller turning ahead while going ahead, turning ahead while going astern, turning astern while going ahead and turning astern while going astern were carried out. At the same time, the thrust and torque coefficients were presented. The simulation results showed good agreement with the results of tank test. The influence of mesh generation and computational domain on open-water performance were also discussed.


1989 ◽  
Vol 26 (03) ◽  
pp. 173-191
Author(s):  
Stephen B. Denny ◽  
Larry T. Puckette ◽  
E. Nadine Hubble ◽  
Susan K. Smith ◽  
Richard F. Najarian

The Combatant Craft Engineering Department began, in the early 1980's, to evaluate a systematic series of propellers representing those available in the commercial market. The primary goal of the program was to generate "open-water" equivalent thrust and torque data, from full-scale trials, to improve propeller selection techniques for small craft and small ships, particularly at high speeds. The first phase of the program investigated three-bladed propellers with systematic variations in pitch ratio as well as propeller blade "cupping." Cupping has been a long-practiced, but ill-defined, art for fine-tuning propeller performance. The second phase, in 1987, expanded the series to include four-bladed propellers. In addition, the propulsion system of the test craft has been changed to achieve higher speeds, and therefore lower cavitation numbers.


2014 ◽  
Vol 66 (2) ◽  
Author(s):  
M. Nakisa ◽  
A. Maimun ◽  
Yasser M. Ahmed ◽  
Jaswar Jaswar ◽  
A. Priyanto ◽  
...  

Marine propeller blade geometries, especially LNG carriers, are very complicated and determining the hydrodynamic performance of these propellers using experimental work is very expensive, time consuming and has many difficulties in calibration of marine laboratory facilities. This paper presents the assessment on the effect of turbulent model and mesh density on propeller hydrodynamic parameters. Besides that, this paper focuses on the LNG carrier Tanaga class propeller hydrodynamic performance coefficients such as Kt, Kq and η, with respect to the different advance coefficient (j). Finally, the results from numerical simulation that were calculated based on RANS (Reynolds Averaged Navier Stocks) equations, were compared with existing experimental results, followed by analysis and discussion sections. As a result the maximum hydrodynamic propeller efficiency occurred when j=0.84.


2021 ◽  
Vol 9 (12) ◽  
pp. 1396
Author(s):  
Fuzheng Li ◽  
Qiaogao Huang ◽  
Guang Pan ◽  
Denghui Qin ◽  
Han Li

In order to improve the hydrodynamic performance of pump-jet propulsion (PJP) when matching stator with the rotor, the RANS method with SST k-ω turbulence model is employed to study the influence of six kinds of stator parameters, which are classified into three groups, i.e., stator solidity, stator angles and rotor–stator spacing (S). Results show that the stator solidity involves the blade number (Ns) and chord length (L), has an obvious acceleration effect at and after stator, and produces a higher thrust and torque with a slight efficiency change. Further comparing Ns and L results, we find greater distinctions between the two cases when stator solidity is greatly adjusted. Three stator angles, i.e., stagger angle (α), lean angle (γ), and sweep angle (β), are studied. The α has the biggest effect on the thrust, torque, and efficiency; meanwhile, it shifts the advance number that corresponds to maximum efficiency. The effect of γ is similar to α, but its influence is far less than α. However, there is little difference between various β cases except for off-design conditions, where the efficiency drops dramatically as β increases. The S has a slight effect on PJP performance. Even though S decreases 34% relative to the original PJP, the rotor thrust and torque increase by less than 1%. In addition, we compare torque balance locations under various parameters, and each component force is analyzed in detail to explain the reason for performance variation. The present work is conducive to future optimization in PJP design.


2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Chun-Yu Guo ◽  
Pei Xu ◽  
Chao Wang ◽  
Wei-Peng Xiong

This experimental study investigates the influence of different sizes, quantities, and axial positions of model ice on propeller hydrodynamic performance. We used particle image velocimetry measurements to analyze the characteristics of the propeller wake flow field. The measurement results show that ice blockage leads to an increase in propeller thrust, torque, and efficiency. The smaller the advance coefficient of the propeller is, the smaller the influence of model ice on propeller blockage is. As the model ice becomes thicker and the thrust and efficiency of the propeller increase, the propeller torque is smaller for low advance coefficient and higher for high advance coefficient. The wider the model ice is, the larger the thrust and torque of the propeller are. Once the model ice width exceeds the propeller diameter, the change in its width has no effect on propeller efficiency. When the propeller is blocked with model ice, the fluid velocity in the wake flow reduces in the inflow direction, and the increase in fluid velocity in the horizontal transverse direction and variation of fluid velocity in the vertical direction are related to the model ice width.


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