Abstract:

The bubble generation process in liquid-solid slurry system in T-junction microchannel was visually investigated by a high-speed camera. The glycerol-water solutions containing 0.35%（mass） of surfactant (SDS) and different concentrations of glass beads were used as the continuous phase, nitrogen as the dispersed phase. The effects of gas and liquid flow rates, particle concentration and superficial viscosity of slurry on the bubble generation frequency and bubble size under the Taylor flow were studied. The results show that under the Taylor flow regime, when the flow rate of the dispersed phase is constant, the frequency of bubble generation increases but its length decreases with the increase of the flow rate of the continuous phase. As the flow rate of the continuous phase is fixed, both the formation frequency and size of bubble increase with the increase of the flow rate of the dispersed phase. When particle concentration increases, the surface tension decreases of the slurry but its superficial viscosity increases, the bubble generation frequency rises while its size declines. A prediction model for bubble size in the T-type microchannel slurry system is proposed, and the model has good prediction accuracy.

Key words: microchannel, bubble, frequency, size, slurry

摘要：

利用高速摄像仪对T型微通道内浆料体系中的气泡生成频率和气泡尺寸进行了研究。以氮气作为分散相，含0.35%（质量分数）表面活性剂（SDS）不同浓度玻璃珠的甘油-水溶液为连续相。实验考察了弹状流下气液两相流量、颗粒浓度以及浆料表观黏度对气泡生成频率及气泡尺寸的影响。结果表明：在弹状流下，当分散相流量一定时，随着连续相流量的增大，气泡的生成频率增大而气泡尺寸减小。当连续相流量一定时，随着分散相流量的增大，气泡生成频率和气泡尺寸均增大。随着颗粒浓度的增大，浆料的表面张力减小，表观黏度增大，气泡生成频率增大而气泡尺寸减小。提出了T型微通道内浆料体系中生成气泡尺寸的预测模型，模型具有良好的预测精度。

关键词: 微通道, 气泡, 频率, 尺寸, 浆料