螺旋桨非定常力的黏性数值分析

基于黏流的数值模拟技术在非均匀来流情况下对DTMB P4119桨所受的非定常力进行了分析.该桨已在DTMB用给定的非均匀轴向进流场做过非定常水动力测量,故本文计算用该进流场作为进流条件并把该试验结果用来验证.计算过程分析了网格数的收敛性. 非定常力的计算的预报结果,明显地反映了1阶,2阶及3阶叶频的轴承力幅值与进流阶调的耦合效应.通过计算结果与试验结果的对比,不论是非定常力的演变特征还是脉动幅度都与试验结果吻合良好.通过简单定性分析认为通过计算得到的非定常力预报螺旋桨线谱噪声误差将在3dB以内,比较理想.

Unsteady hydrodynamics forces of propeller predicted with viscous CFD

Based on numerical simulation in viscous flow, the unsteady thrust and torque of propeller DTMB 4119 was predicted. Since that propeller was test in a given non-uniform axial inflow in DTMB, that inflow condition was adopted in present analysis and that test results can be used for validation. The grid convergence was verified in the present study. The results of predicted thrust and torque clearly presents the couple effect between wake harmonics and 1st, 2nd and 3rd blade frequency forces. The comparisons between the calculated and experimental forces show good agreement with each other. After a qualitative analysis, the error of noise prediction based on the calculated unsteady forces will be within 3dB expected, which includes the error caused by the error of force prediction so it seems a satisfactory result.