Comparative analysis of the hydrodynamic performance of pre-swirl stator pump-jet propulsor under different rotational speeds

The pump-jet propulsor(PJP) performances under various rotational speeds (20~50 r/s) are analyzed for further studying the influence of the Reynolds number ( Re ) on the hydrodynamics of PJP, before this, the calculation model is verified by using the experiment data, it proves the present numerical method is proper to make a further study. The results indicate both the hydrodynamic coefficients of PJP and PJP components and the contours with dimensionless variables are present high similarity, yet the Re has the slight effect on the components performance, among which, the force coefficient of rotor is the least affected, with a relative error no more than 1%. Followed is the force coefficient of rotor stator, the maximum error is 2.1%, since the force of duct and stator is so low that has the slight effect on PJP, the total force error is less than 2%. However, the torque coefficient error is bigger with a value of about 3%. Besides, it is found that all hydrodynamic coefficients vary monotonically with rotating speed, the higher Re caused by increasing the rotational speed will contribute to enhance the work ability of rotor, thus cause a lower pressure at vortex core, and change the trajectory of TLV. 为深入探讨由转速改变引起雷诺数的变化对泵喷推进器性能的影响，采用数值方法基于物理实验数据验证了计算模型，对不同转速（20~50 r/s）下泵喷性能进行了研究，结果表明性能系数曲线和无量纲处理后的云图均有一定的相似性，但雷诺数对各部件性能稍有影响，其对桨叶推力系数影响最小，相对偏差不超过1%；导叶推力系数次之，最大偏差为2.1%；由于导管和导叶提供推力相对较小，对泵喷系统影响甚小，最终总推力系数偏差小于2%。而扭矩系数的偏差稍大，最大接近3%。分析发现各性能偏差随转速单调变化，转速增大所引起的雷诺数提高加强了桨叶做功能力，进而导致TLV涡核压力降低，改变了TLV的运动轨迹。