绝热和加热状态下换热器壳侧气液两相流的流型与压降

Two-Phase Flow Pattern and Pressure Drop on the Shell-Side of Heat Exchanger during Adiabatic and Heating FLow

对甘油水溶液 空气在TEMA F型换热器壳侧绝热及加热 (液相有少量蒸发 )状态下的气液两相流流型和压降进行了研究 .研究表明 ,热态时的流型及其转变与绝热时有较大差别 .在无量纲量Frm 和Jg/Jl 的坐标系中 ,首次获得了同时适用于绝热和加热状态的通用流型图 .在不同流型下 ,按窗口区、错流区用Martinelli参数关联了两相摩擦压降 ,获得了较高精度的关联式 .拟合结果说明 ,对环状流与分层流 ,在绝热和加热状态下的系数C值近于相等 .

An experimental investigation has been carried out to evaluate the flow pattern and pressure drop on the shell side of a TEMA*.F heat exchanger. The fluid is made of glycerine-water solution 60% by weight and air mixture. It appears from present experiment that the flow pattern and their transition are guite different during adiabatic and heating flow. A generalized dimensionless flow pattern map is presented using a modified Froude number. According to different flow pattern, the Martinelli model is used to correlate friction pressure drop of window zone and cross zone. It is found that much accurate correlations of pressure drop are obtained and the coefficient C in equation (6) is nearly the same during the adiabatic and heating flow in annular and stratified flow.