Numerical Prediction for Subcooled Boiling Flow of Liquid Nitrogen in a Vertical Tube with MUSIG Model  

作　　者：王斯民 文键 李亚梅 杨辉著 厉彦忠 JiyuanTu 

机构地区：[1]School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China [2]School of Aerospace, Mechanica-1 and Manufacturing, RMIT University, VIC 3083, Australia

出　　处：《Chinese Journal of Chemical Engineering》2013年第11期1195-1205,共11页中国化学工程学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China （51106119, 81100707）, the Fundamental Research Funds for the Central University of China, Doctoral Fund of Ministry of Education （20110201120052） and the National Science and Technology Sur0orting Item （2012BAA08B03）.

摘　　要：Multiple size group （MUSIG） model combined with a threedimensional twofluid model were em ployed to predict subcooled boiling flow of liquid nitrogen in a vertical upward tube. Based on the mechanism of boiling heat transfer, some important bubble model parameters were amended to be applicable to the modeling of liquid nitrogen. The distribution of different discrete bubble classes was demonstrated numerically and the distribu tion patterns of void fraction in the wallheated tube were analyzed. It was found that the average void fraction in creases nonlinearly along the axial direction with wall heat flux and it decreases with inlet mass flow rate and sub cooled temperature. The local void fraction exhibited a Ushape distribution in the radial direction. The partition of the wall heat flux along the tube was obtained. The results showed that heat flux consumed on evaporation is the leading part of surface heat transfer at the rear region of subcooled boiling. The turning point in the pressure drop curve reflects the instability of bubbly flow. Good agreement was achieved on the local heat transfer coefficient aalnst experimental measurements, which demonstrated the accuracy of the numerical model.Multiple size group(MUSIG) model combined with a three-dimensional two-fluid model were employed to predict subcooled boiling flow of liquid nitrogen in a vertical upward tube. Based on the mechanism of boiling heat transfer, some important bubble model parameters were amended to be applicable to the modeling of liquid nitrogen. The distribution of different discrete bubble classes was demonstrated numerically and the distribution patterns of void fraction in the wall-heated tube were analyzed. It was found that the average void fraction increases nonlinearly along the axial direction with wall heat flux and it decreases with inlet mass flow rate and subcooled temperature. The local void fraction exhibited a U-shape distribution in the radial direction. The partition of the wall heat flux along the tube was obtained. The results showed that heat flux consumed on evaporation is the leading part of surface heat transfer at the rear region of subcooled boiling. The turning point in the pressure drop curve reflects the instability of bubbly flow. Good agreement was achieved on the local heat transfer coefficient against experimental measurements, which demonstrated the accuracy of the numerical model.

关 键 词：liquid nitrogen subcooled boiling bubble departure diameter bubble frequency nucleation site den-sity MUSIG model 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TD94[动力工程及工程热物理—热能工程]