航空发动机滑片泵数值模拟

Numerical simulation on an aero-engine vane pump

利用计算流体力学软件Star-cd二次开发功能模拟了某一航空发动机滑片泵的内部流场,分析了计算中是否引入空化模型对计算结果的影响,以及滑片泵定子和滑片间隙大小对滑片泵性能的影响,预测了不同工况下,滑片泵内出现空化的位置和区域大小.计算结果表明:由于滑片泵叶片转动,从而引起空化区域范围的缩小和增大,泵油量也相应地增加和减小,使得滑片泵进口瞬时流量较为平稳,而出口瞬时流量有较大的脉动,进、出口周期平均流量与计算总平均流量的误差小于1.5%,计算总平均流量与该滑片泵样件的台架实验测试结果之间的误差小于3%;滑片泵转子叶片与定子壁面间隙增大,泄漏量增加,滑片泵的平均流量减小;间隙为0.07mm的滑片泵计算总平均流量相对于间隙为0.02mm的计算总平均流量减小3.1%.从计算结果可以推断,滑片泵的进口流道应与吸油腔正对,可以减少进口流道内空化区域和流动阻力.

The internal flow field of an aero-engine vane pump was simulated with the function of the secondary development of computational fluid dynamics software Star-cd.The impacts of incorporating/neglecting the cavitation model on simulation results,the gap size between the tip of vane and stator of vane pump were analysized.The sizes and positions of cavitation in vane pump were predicated under different working conditions.The simulation results demonstrate that cavitation is generated,developed and collapsed during the rotation of rotor,which leads to accumulation and release of the mass of oil,correspondingly to a reduced and increased area of cavitation respectively,and the transient volume flow rate of inlet is stable while that of outlet fluctuates significantly.The simulation results show the difference between cycle averaged valume flow rate at inlet/outlet and total averaged volume flow rate is less than 1.5%,and the difference between total averaged volume flow rate and averaged volume flow rate obtained from the experiment of the vane pump is less than 3%.The simulation results also demonstrate that expanding the gap between the tip of vane and the stator results in a decrease of the average volume flow rate of the vane pump and an increase in the leakage,which can be seen from that the averaged volume flow rate of the gap size equaling 0.07 mm is reduced 3.1%relative to that of the gap size equaling 0.02 mm.It is estimated that if the inlet duct is designed to face the suction port,the flow resistance andthe area of cavitation can be reduced.