小流量工况下微小型泵内部流场数值模拟及LIF-PIV实验研究

NUMERICAL SIMULATION AND LIF-PIV EXPERIMENTAL INVESTIGATION ON INNER-FLOW OF A MINI PUMP UNDER LOW FLOW RATE CONDITION

本研究利用二维粒子图像测速技术(PIV),并结合激光诱导荧光(LIF)的示踪颗粒技术,成功地测量了小流量工况下微小型离心泵的内部流场,得到了泵内喉舌区和叶道间的瞬时流场,并且用标准κ-ε湍流模型对试验工况进行计算.LIF示踪颗粒的使用成功地消除了近壁和角区的激光反光干扰,近壁区测试数据得到改善。试验和计算结果证明,标准κ-ε湍流模型对小流量工况下的泵的性能预测非常准确但是对于捕捉流动细节信息来说,则显得不是很合适。LIF-PIV测量揭示了微小型离心泵在小流量工况下,喉舌处存在大量的回流区域而且不同的叶道的流动状态也不相同.

In the presented study a Planar PIV combined with LIF tracer technique was applied for the experimental investigation on inner-flow of a mini centrifugal pump, by means of the laser induced fluorescent tracer, reflected and/or refracted laser light from near-wall was eliminated, the transient flow fields near the tongue and between the impeller blades were successfully measured under the low flow rate condition. Numerical simulation based standard κ-ε turbulence model was compared with the experiment results. It was found that the detailed flow fields under low flow rate condition from numerical simulation was obviously different from the experimental results, despite that its performance prediction is very well. Additional the experimental results reveal that under low flow rate condition of the mini pump, there is a big inverse flow field near the tongue and the flow pattern in the impeller channels became different.