撞击流反应器内流场特性的激光多普勒测速实验与模拟

Laser Doppler Velocimeter Measurements and Numerical Simulation for Flow Characteristics in Impinging Stream Reactor

采用激光多普勒测速仪(LDV)与Fluent数值模拟相结合的方法研究了撞击流反应器内流场特性。通过对比两种方法得到的径向位置r/R=1,Z=±9两点处竖直方向速度大小,验证了本文采用的Fluent数值模拟方法研究撞击流流场的可靠性,并分析了误差存在的原因。同时,数值模拟结果显示,重力的存在造成撞击流流场的不对称分布,转速为200 rpm、400 rpm、600 rpm、800 rpm相对应的撞击面向上偏移的距离分别为1.21 mm、1.61 mm、1.685 mm和1.766 mm。随着桨叶转速的增大,反应器内湍动强度明显呈增强趋势,最大湍动强度依次为1.49%、3.00%、4.53%、6.04%。观察湍流强度场分布云图可得出撞击流明显加强了反应器内湍流强度。

The flow characteristics in impinging stream reactor were investigated with Laser Doppler Velocimetry(LDV)and Fluent numerical simulation.The Fluent numerical simulation method in this paper was proved to be correct to study the reliability of impinging stream flow field by comparing with the experiment values from two points.The two points located at the position of Z=±9,while the radial position is r/R=1.Meanwhile,the numerical simulation results show that the asymmetry distributes of impinging stream flow field results from gravity.The reason of the error between the numerical simulation and experiment were analyzed at the same time.The upward offset distance of the impinging face is 1.21 mm,1.61 mm,1.685 mm and 1.766 mm at the speed of 200 rpm,400 rpm,600 rpm and 800 rpm respectively.The turbulence intensity in the reactor is enhanced significantly when the rotate speed of paddle increases,and the maximum of turbulence intensity is 1.49%,3.00%,4.53%and 6.04%.It can be concluded from the cloud charts of turbulence intensity distribution that impinging stream enhances the turbulence intensity in the reactor obviously.