中国化学工程学报(英文版)
中國化學工程學報(英文版)
중국화학공정학보(영문판)
CHINESE JOURNAL OF CHEMICAL ENGINEERING
2013年
11期
1195-1205
,共11页
王斯民%文键%李亚梅%杨辉著%厉彦忠%Jiyuan Tu
王斯民%文鍵%李亞梅%楊輝著%厲彥忠%Jiyuan Tu
왕사민%문건%리아매%양휘저%려언충%Jiyuan Tu
liquid nitrogen%subcooled boiling%bubble departure diameter%bubble frequency%nucleation site den-sity%MUSIG model
Multiple size group (MUSIG) model combined with a three-dimensional two-fluid 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 wall-heated 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 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.