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

• Published in: Chinese journal of chemical engineering Vol. 21; no. 11; pp. 1195 - 1205
• Main Author: 王斯民 文键 李亚梅 杨辉著 厉彦忠 JiyuanTu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2013
• Subjects: Boiling; bubble departure diameter; bubble frequency; Heat flux; Heat transfer; Liquid nitrogen; Mathematical models; MUSIG model; nucleation site density; subcooled boiling; Tubes; Void fraction; Walls; 垂直管; 局部传热系数; 平均孔隙度; 数值预报; 模型参数; 流动; 液态氮; 过冷沸腾; liquid nitrogen; MUSIG model; subcooled boiling; bubble frequency; nucleation site density; bubble departure diameter
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/S1004-9541(13)60632-1

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.