撞击流中颗粒旋转特性

Particle rotation characteristics in impinging streams

搭建了研究撞击流中颗粒旋转特性的气固两相撞击流实验台,使用高速摄像机拍摄一个截面为0.15 m×0.08m的撞击区域内固体颗粒的运动。利用所搭建的实验台设置了单喷口和双喷口两种实验方式来研究颗粒旋转影响因素,得出撞击流内颗粒的旋转特性。结果表明:固体颗粒在气相中运动过程一直伴随着其自身的旋转;气相场对颗粒转速的影响较小,可忽略不计;相同实验条件下,颗粒直径越小其转速越大;颗粒以及气相速度越大,则固体颗粒在碰撞后的转速越大,当加速气相速度为25 m·s-1,氧化铝陶瓷直径为0.003 m时,颗粒碰撞前后转速差平均值可达280 r·s-1;颗粒间碰撞过程中,颗粒相对运动偏置角度对转速变化影响很小。

An experimental device of gas-solid impinging streams was built up to study particle rotation characteristics. High-speed video camera system was used to observe particle motion in area of 0.15 m × 0.08 m. The influence factors of particle rotation were studied by using this experimental device with single injection or double injections. The particle rotation characteristics was obtained by analyzing those research data. The results showed that the particles always rotated when moving along the gas-solid impinging streams. The influence of gas on particle rotation was relatively small, and therefore it can be ignored. The average rotation speed of particles with smaller diameter was higher than that with greater diameter under same experimental conditions. Those particles with relatively higher velocity before collision were inclined to have a higher rotational speed after collision. The average difference between particle rotation speeds before and after collision can reach 280 r·s^-1 at gas velocity 25 m·s^-1 and diameter of alumina cement 0.003 m. The direction of particle motion has little influence on the particle rotation speed during collision.