基于动量流量法对喷水推进系统推力的CFD计算

采用结构化网格与非结构化网格相结合的方式划分了喷水推进系统的流场区域,采用稳态多参考系方法进行了数值计算。在此基础上,定义并求解一用户自定义标量函数标记整个流场,并根据标记结果将被喷水推进器吸入的流体与其它流体区分开。在后处理过程采用标量函数的等值面来确定喷水推进系统控制体上的流管分界面和进流面。利用数值计算所得的速度场对喷水推进系统喷口和进流面上的动量流量变化率进行计算,间接地得到喷水推进系统的推力。计算结果表明,采用CFD手段计算和分析喷水推进系统包括推力在内的各项性能指标是可行的。

Thrust computation of waterjet propulsion system based on momentum flux method and CFD code

The flow field of a waterjet propulsion system,which is meshed by structural and unstructural grids,was calculated numerically with the steady state multiple frame of reference method.Then a user-defined-scalar function was solved to mark the field,where the fluid ingested by waterjet was distinguished from others by the scalar values.The dividing surface and capture area in the control volume of waterjet system were created by the virtue of an iso-surface about the scalar on post-processing.The thrust acting on hull could be derived indirectly from the difference of momentum flux between the nozzle and inlet capture area.The predicted results indicate that the computational fluid dynamics is effective in calculating and analyzing the characteristics of the waterjet propulsion system.