气固两相流中颗粒时均速度的测量新方法

A New Method for the Measurement of Solids Time-averaged Velocity in GasSolid Two-phase Flow

根据互相关测速技术提出了一种测量颗粒时均速度的新方法,与Aguillon和Nieuwland提出的方法相比,本方法不仅考虑了采样时间内向上及向下运动颗粒微元体的速度和数量变化,而且还考虑了所测颗粒微元体的浓度变化. 为了比较几种测量方法间的差别,采用PV4A型光纤测量仪,在循环流化床冷态实验装置上测量了不同操作条件下的颗粒速度,并对3种方法的计算结果进行了对比. 结果表明,在高气速、低颗粒浓度条件下,3种方法计算的颗粒时均速度相差较小,而在低气速、高颗粒浓度条件下,3种方法计算的颗粒时均速度相差较大,并且本文方法所计算的颗粒质量流率与实际测量值最接近.

A new method for calculating time-averaged particle velocity was presented based on the cross- correlation technique. Compared with the other two calculating methods presented by Aguillon and Nieuwland, the new method considers not only the differences between the upward and downward particle element velocities and numbers, but also the differences of particle element concentrations. The measurement of particle time-averaged velocity was completed by using a PV4A optical fiber probe in a cold model set-up of circulating fluidized bed for the sake of ascertaining the differences between the new one and the others. The results show that the differences between them were negligible under higher superficial gas velocity and lower cross-sectional average particle concentration, while the differences were remarkable under lower superficial gas velocity and higher cross-sectional average particle concentration.