涡旋液泵内部非稳态流场的数值模拟

采用动网格技术对涡旋液泵内的非稳态流动进行了数值模拟,得到了泵在各个转角下的压力、速度、空泡体积分数,以及进出口流量和监控点的压力参数。结果表明,涡旋液泵内的流动是一种非稳态、非均匀,非对称的流动。动静圈的啮合间隙处因大压差和小流通面积而存在高速射流现象,并在啮合间隙下游出现负压区和空化。泵进口位置的偏移和动盘对腔外流体的推动使左右两个吸液腔的流动不对称,将造成涡盘受力的不平衡。在吸液即将结束时,因涡旋液泵对液体的挤压作用,在大约20°的转角范围内,泵的工作腔内出现极大幅值的压力脉动,严重危害泵的安全可靠运行。

Numerical Simulation of the Transient Flow in a Scroll Hydraulic Pump

The transient flow in a scroll hydraulic pump was numerically simulated with the dynamic mesh technology. The pressure,velocity and bubble volume fraction in the flow flied were figured out at different crank angles. Besides,the inlet and outlet volume rate,the pressure at the monitoring point were obtained. The results indicated that the flow in the pump is transient,inhomogeneous and asymmetrical. The high speed jet flow caused by high pressure difference and narrow passage happens at the engaging clearance,which results in the negative pressure and the cavitations at that place. The fluid flied in the pair of symmetric suction chamber is asymmetrical as the forces on the scroll plates can not be balanced by each other,because the location of the inlet port and the motion of orbiting scroll are asymmetrical. At the end of the suction process,about 10 degree before and after the end angle( 360°),the liquid in suction chamber is squeezed by the scroll walls so that its pressure reaches a large value suddenly. The high pressure fluctuation will make the pump down and even damaged.