A research of heat transfer enhancement of rectangular channel with dimples

Zhe Fu,Yang Jiao,Zhihong Yan,Xizhi Zhou,Yingping Qian,L Zhao,J Cai,L You,A Xavior

doi:10.1051/matecconf/201710004001

Abstract

this thesis is aimed to do numerical simulations on rectangular channel with a new model of dimple in different condition of channel height, dimple depth, dimple distance by using CFD program and RNG k-e model. It is concluded that, the existence of dimple has changed the velocity and direction of the fluid, as well as the original flow status. Dimple increased the heat exchange area of rectangular channel and broke the boundary layer, enhanced the flow rate of fluid, as a result of enhanced heat transfer performance.

Highlights

In recently technology of heat transfer enhancement, in order to enhance the ability of heat exchange in fluid, most employers use the methods of roughen layer surface and extend the surface area
The factors of heat exchange and flow friction in dimple heat transfer enhancement are mainly affected by the shape, depth, distance, Re of dimple
Burgess [4] used air as medium and analyzed the effect of dimple depth, discovered that heat exchange factor η and friction factor are increased by the depth went up

Summary

Introduction

In recently technology of heat transfer enhancement, in order to enhance the ability of heat exchange in fluid, most employers use the methods of roughen layer surface and extend the surface area. The heat transfer enhancement of dimple breaks the boundary layer because of the sunken surface, and creates different sizes of vortex which accelerates the heat exchange in rectangular channel. The factors of heat exchange and flow friction in dimple heat transfer enhancement are mainly affected by the shape, depth, distance, Re of dimple. J [6] has done the analysis of how the distance and depth and concentration affect heat transfer, ending up with found a best way to design heat transfer enhancement. The author analyzed that in different Re, the effect of channel height, dimple depth, dimple distance on heat transfer and friction in a new dimple and after that analyzed the integrated heat transfer performance under different individual working conditions

Objectives

Results

Conclusion