Study of Thermal and Hydraulic Performances of Circular and Square Ribbed Rough Microchannels Using LBM  

作　　者：M.A.Taher H.D.Kim Y.W Lee 

机构地区：[1]Department of Mechanical and Automotive Engineering, Pukyong National University [2]Department of Mechanical Engineering, Andong National University

出　　处：《Journal of Thermal Science》2015年第6期549-556,共8页热科学学报（英文版）

摘　　要：The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this problem.In micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is used.The roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel height.The friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness effects.The thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of geometries.The results have been compared with previous published works and it is found to be in very good agreement.

关 键 词：LATTICE-BOLTZMANN Friction factor Knudsen number Surface Roughness 

分 类 号：TH117[机械工程—机械设计及理论] TK124[动力工程及工程热物理—工程热物理]