The Analysis Of Propulsion Performance On Mainstream Ship Propeller In Xi Jiang Line

With the development of Xijiang line as a national strategy,both the number of ships and the tonnage of ships on the whole line have increased rapidly,and the propeller is used as a mechanical device to promote the movement of ships.Taking the role of transforming the power generated by the diesel engine into the propulsion force which can control the ship's motion,so the propeller propulsion performance will greatly affect the ship's navigation speed and operating cost.Therefore,it is a great practical significance to analyze the propelling performance of mainstream ship propellers in Xijiang line under the background of constructing golden waterway.The main work accomplished is as follows:(1)generating ship hull and propeller model and simulation calculation model.The hull modeling work is completed by using the CAD drawing of the mainstream ship hull of Xijiang line.The effective horsepower of the hull is calculated and the design parameters of the propeller are obtained after preliminary design and final design according to the B type design atlas.The model of the propeller is constructed,and the simulation model is built in the pre-processing of CFD software Fluent.(2)The propeller propulsion performance in uniform flow field and non-uniform flow field is analyzed.The simulation results of three turbulence models and SM model in the uniform flow field are calculated and compared with the experimental data of the ship pool.The results show that the Reliable turbulence model and the SM model have the highest accuracy,and the analysis of propeller propulsion performance in the non-uniform flow field shows that the non-uniform flow will directly change the flow velocity in front of the propeller disk and then affect the pressure distribution on the propeller disk surface.The thrust value and torque value of single blade fluctuate greatly at different circumferential position,but have little effect on the whole,and it can be seen that the propeller thrust and torque in non-uniform flow field are higher than that in uniform flow field.(3)The effect of hollow flow field on propeller propulsion performance is analyzed.In the uniform flow field,the effects of cavitation on propeller propulsion performance under different turbulence models,different cavitation models and different cavitation numbers are analyzed respectively.The results show that SST model is more suitable for analyzing propeller propulsion performance under cavitation than other turbulence models,and the difference between the two models in propeller propulsion performance is very small,and the cavitation number decreases with the decrease of cavitation number.The occurrence and development of cavitation phenomenon is more obvious,and the cavitation phenomenon will occur at higher speed advance coefficient,corresponding to the thrust,and the speed advance coefficient with the sharp decrease of torque will be increased accordingly,thus the influence on the propulsion performance will be increased accordingly.(4)The influence of propeller structure parameters on propeller propulsion performance is analyzed.The pitch and longitudinal angle of propeller are changed in a certain range.The results show that the propeller thrust coefficient,the torque coefficient and open water efficiency are influenced by the change of propeller pitch in uniform flow field,and the thrust and torque from propeller become larger with the pitch increasing in a certain range.The open water efficiency can be improved by reducing the pitch properly.Although the change of longitudinal angle has little effect on the propeller's thrust,torque and open water efficiency,but the hull induced vibration caused by propeller running can be alleviated by properly increasing the longitudinal angle.