受气液两相流横向冲刷的圆柱表面压力分布研究

Pressure Distributions around Circular Cylinder for Gas Liquid Two Phase Cross Flow

在１．６×１０４～５．０×１０４的Ｒｅ数范围和０～０２的含气率范围内，利用微型压力传感器和旋转工作台，对垂直上升矩形截面管内由空气和水组成的气液两相流绕水平布置圆柱流动时圆柱表面的压力分布进行了实验研究，得出了时均压力系数分布和脉动压力系数分布随含气率及Ｒｅ数的变化特性．从这些特性中可以看出，气液两相流中圆柱背侧的旋涡从层流分离开始向紊流分离转变的临界Ｒｅ数比单相流时低得多；当含气率超过０１时，在圆柱背部的尾流中不再产生明显的涡街；用脉动压力分布可以比时均压力分布更清楚地表明旋涡的强度及分离位置．本实验范围内Ｒｅ数对时均压力和脉动压力分布的影响都很小．

Pressure distribution of a circular cylinder under gas liquid two phase cross flow is investigated experimentally for Reynolds number from 1.6×10 4 to 5.0×10 4.The vertically upward two phase flow is bubbly in character. Downstream vortex street disappears as the void fraction exceeds 0.12 . Results indicate that the pressure distribution is almost independent of Reynolds number for the range treated. The critical Reynolds number at which the vortex street separation occurs as transition from laminar to turbulent flow is reduced enormously in a gas liquid bubbly flow.