气-液两相流中颗粒迁移及其对液膜沉积的影响

Particle migration in gas-liquid two-phase flow and its effect on liquid film deposition

通过微流控试验研究了液体中悬浮颗粒对微通道气-液两相驱替的影响规律,并解释了其微观机理。试验结果表明,驱替速度和颗粒体积分数会显著影响颗粒在通道壁的滞留及液膜沉积厚度。驱替速度较小时,颗粒不会被液膜夹带,且颗粒的存在对液膜厚度的影响可以忽略;驱替速中等时,颗粒会导致液膜厚度明显增加;随着驱替速度进一步增大,膜厚与颗粒体积分数的相关性减弱。此外,基于受力分析以及润滑理论推导的理论模型较好地预测了颗粒在通道中滞留的临界条件,并与试验结果吻合良好。

The influence of suspended particles on gas-liquid two-phase displacement in micro-channel is studied by micro-fluidic experiments, and the relevant microscopic mechanism is explained. The experimental results show that the displacement flow rate and particle volume fraction significantly affect the retention of particles in channel wall and the thickness of deposited liquid film. Particles cannot be entrained when the displacement flow rate is very small, and the effect of the existence of particles on the film thickness can be ignored. The thickness of liquid film increases obviously with the presence of particles at intermediate displacement flow rates. With further increase of displacement flow rate the correlation between the film thickness and the particle volume fraction becomes weaker. In addition, the theoretical model based on the lubrication theory and force analysis can predict the critical condition for particle entrainment in the channel, and is consistent with that of experimental results.