伴随方法在喷水推进器进流研究中的应用

Application of Adjoint Method in the Study of the Intake Flow in a Waterjet

进口流道是喷水推进器的主要部件之一,其水力损失是推进器总损失的重要部分。进口流道几何结构引起推进泵非均匀进流,对推进器水力效率和动态激励造成不利影响。该文采用伴随方法对喷水推进器进口流道开展数值研究,先正向求解流动方程后,再反向求解伴随方程,基于伴随变量场得到与进流最相关的流动区域,建立并验证了基于伴随方法的喷水推进器流道进流面获取方法。以进口流道边界为设计输入变量,以出口流动不均匀度为目标,通过伴随方法来优化流道几何,经过8次迭代后,出口不均匀度相对下降幅度达到18.7%,验证该方法可有效优化进口流道几何。

The intake duct is one of the main components of a waterjet,and the hydraulic loss in the intake duct is an important part of the total loss of the waterjet.The geometry structure of the intake duct induces non-uniform inflow of the propulsion pump,which has adverse effects on the hydraulic efficiency and dynamic excitation of the waterjet.The intake duct of the waterjet is numerically simulated by using the adjoint method,the flow equations are first solved in the forward direction,then followed by the reverse solution of the adjoint equations.The flow region most related to the inflow is obtained based on the field of the adjoint operator.The method to capture the inflow surface of the waterjet duct based on the adjoint method is then established and verified.The duct geometry is optimized through the adjoint method by ta king the boundary of the intake duct as the design input variable and the non-uniformity of the outflow as the objective.After 8 iterations,the non-uniformity of the outflow relatively decreases 18.7%,which validates that the adjoint method can effectively optimize the geometry of the intake duct.