气固两相对撞流颗粒运动特性分析

Experimental Investigation on the Particle Behavior of Gas-Particle Two Phase Flow in Round Opposed Jets

本文采用PIV两相同时测量方法,对低载荷气固两相双喷嘴对置撞击射流中的颗粒运动特性进行了研究。实验中轴向射流出口雷诺数为Re=14500,喷嘴内径为d=10 mm,喷嘴间距为L/d=12;颗粒相采用平均直径为dp=100μm的实心玻璃微珠,圆管加速段中的颗粒质量载荷控制为1%~4%。研究结果表明,低载荷下撞击射流中的颗粒间碰撞可忽略,颗粒浓度在喷嘴附近达到峰值;惯性使得颗粒轴向速度在穿入到反向射流前缓慢衰减,之后迅速减小;颗粒在撞击区形成高湍动区域,进而强化了颗粒相的混合效应。

Experimental investigation on the particle behavior of a dilute gas-particle flow in round opposed jets was conducted using a simultaneous two-phase PIV measurement technique.The Reynolds number(based on the bulk velocity U_0 of the jet at the nozzle exit and nozzle inside diameter d) is 14500,and the nozzle spacing L/d is 12.Glass beads with the averaged diameter of 100 μm are used as dispersed phase,and three low mass loading ratios(Φ_m) ranging from 1% to 4% are tested.It is found that the inter-particle collision can be neglected even at Φ_m= 4% and the maximum particle concentration occurs near the nozzle exit.Before the particles penetrate into the reverse jet,due to its larger inertial,the axial velocity of the particle-phase decays slowly.After that,the axial velocity of the particle-phase decreases rapidly.In the impingement zone,the leftwards- and rightwards-moving particles form a high turbulent region,which reinforces particle mixing and also improves the performance of opposed jets in terms of heat and mass transfer.