Two-Phase Flow Pressure Drop of Liquid Nitrogen Boiling in the Straight Section Downstream of U-Bend  

作　　者：邓冬 谢斯卫 汪荣顺 

机构地区：[1]School of Mechanical Engineering,Shanghai Jiaotong University

出　　处：《Journal of Shanghai Jiaotong university(Science)》2014年第4期495-501,共7页上海交通大学学报（英文版）

基　　金：the National Natural Science Foundation for Young Scholars of China(No.50806042)

摘　　要：The gas-liquid(two-phase) flow pressure drop of liquid nitrogen boiling in the straight section downstream of U-bend is investigated experimentally. The mass flux ranges from 32 to 280 kg/(m2· s). The inlet pressure of U-tube is from 140 to 272 kPa. And the curvature ratio is from 6.67 to 15. The tube wall including the U-bend is heated uniformly and the heat flux ranges from 0 to 22 kW/m2. The tube with higher inlet pressure has higher pressure drop in the downstream section of the bend. The bended degree of the U-bend influences the pressure drop in the downstream straight section of U-bend. A new correlation taking the effect of the secondary flow into account is proposed for the two-phase slip speed ratio. The pressure drop in the straight section downstream of U-bend calculated by the new correlation agrees well with experimental measurements.The gas-liquid （two-phase） flow pressure drop of liquid nitrogen boiling in the straight section downstream of U-bend is investigated experimentally. The mass flux ranges from 32 to 280 kg/（m2. s）. The inlet pressure of U-tube is from 140 to 272 kPa. And the curvature ratio is from 6.67 to 15. The tube wall including the U-bend is heated uniformly and the heat flux ranges from 0 to 22 kW/m2. The tube with higher inlet pressure has higher pressure drop in the downstream section of the bend. The bended degree of the U-bend influences the pressure drop in the downstream straight section of U-bend. A new correlation taking the effect of the secondary flow into account is proposed for the two-phase slip speed ratio. The pressure drop in the straight section downstream of U-bend calculated by the new correlation agrees well with experimental measurements.

关 键 词：pressure drop downstream of U-bend secondary flow liquid nitrogen 

分 类 号：TB75[一般工业技术—真空技术]