Rib height selection for roughness-enhanced tube  

作　　者：黄维军 

机构地区：[1]The Key Laboratory of Enhanced Heat Transfer and Energy Conservation Under the State Ministry of Education, School of Chemical and Energy Engineering, South China University of Technology

出　　处：《Journal of Chongqing University》2006年第1期8-12,共5页重庆大学学报（英文版）

基　　金：Funded by Major State Basic Research Development Program of China (Grant No. G2000026301)

摘　　要：In this study we proposed a method of selecting preferred rib height of roughness-enhanced tubes by combining the boundary layer district theory with Blasius friction correlation. This method calculates the thickness of every layer for the smooth tube, which is helpful in determining the range of optimum roughness size for roughen-surface enhanced tubes. We computed the flow and heat transfer in these optimum tubes by numerical simulation, investigated the three ways of performance evaluation criteria, and selected the best rib height by directly choosing the tube which had the highest heat transfer efficiency. For the air flow at Re number 10 000 in a converging-diverging tube with a 44 mm inner diameter, the optimal rib height is in the range from 1.6 mm to 2.4 mm; and in a transversely-ridged tube with an inner diameter of 34 mm, from 1.0 mm to 1.5 mm. The preferred rib height changes with flow Re number, fluid properties, and inner diameter of tube, also varies with the tube shape. However the tube shape does not exert so much impact as other factors.In this study we proposed a method of selecting preferred rib height of roughness-enhanced tubes by combining the boundary layer district theory with Blasius friction correlation. This method calculates the thickness of every layer for the smooth tube, which is helpful in determining the range of optimum roughness size for roughen-surface enhanced tubes. We computed the flow and heat transfer in these optimum tubes by numerical simulation, investigated the three ways of performance evaluation criteria, and selected the best rib height by directly choosing the tube which had the highest heat transfer efficiency. For the air flow at Re number 10 000 in a converging-diverging tube with a 44 mm inner diameter, the optimal rib height is in the range from 1.6 mm to 2.4 ram; and in a transversely-ridged tube with an inner diameter of 34 ram, from 1 .0 mm to 1.5 mm. The preferred rib height changes with flow Re number, fluid properties, and inner diameter of tube, also varies with the tube shape. However the tube shape does not exert so much impact as other factors.

关 键 词：粗糙管 边界层理论 光滑管 肋条 高度 

分 类 号：TK172.4[动力工程及工程热物理—热能工程]