喷水推进船自航功率特性数值计算与分析

Numerical Calculation and Analysis of Self-propulsion Power Characteristics of Waterjet Driven Ship

喷水推进船的功率传递和推进效率成分与螺旋浆推进存在着显著差别。论文针对一艘喷水推进三体船,基于求解RANS方程,采用稳态多参考系(MRF)模型来模拟实泵,进行了带自由液面的喷水推进三体船自航数值模拟,并基于国际拖曳水池会议(ITTC)推荐的动量通量法对喷水推进的功率传递和效率分量进行分析,得到喷水推进总效率及其效率分量在不同航速下的变化规律。数值计算结果与自航试验结果吻合良好,表明该数值计算方法可以准确地预报喷水推进船体的自航性能。在低速时,推力减额主要受阻力增额分数的影响;在整个航速范围内,流道的效率和泵的效率随航速的变化不大。提高喷水推进总体效率要从提高流道效率、理想喷水效率和水泵效率入手。通过对功率传递和推进效率成分的分析,不仅能更好地理解船体-喷水推进的相互关系,而且根据计算得到的效率成分变化规律可以进行喷水推进器功率的估算,从而选择与之相匹配的主机,具有一定的学术科研价值和工程应用价值。

Power transfer and propulsion efficiency components of water jet propulsion ships are significantly different from that of traditional propellers propelled ships.In order to research self-propulsion power characteristics of waterjet propelled ships,numerical simulation of self-propulsion of a waterjet propelled trimaran is carried out by solving the RANS equation and applying the multi-reference frame model for the rotation of impellers.Based on the momentum flux method recommended by the International Towing Tank Conference,power transfer and efficiency of the waterjet trimaran are analyzed.It is found that computed results are in good agreement with measured results,and the present method can accurately predict self-propulsion performance of the waterjet ship.Within low-speed,total thrust deduction is mainly influenced by the fraction of the resistance increment.Duct efficiency and pump efficiency are not changed significantly with the increase of the hull speed.Interaction between the waterjet and the hull is revealed,and improvement of duct efficiency,ideal jet efficiency and pump efficiency are necessary for improving overall efficiency.This paper may have a certain academic research value and engineering practical value.