Thermal Performance Assessment for Laminar Forced Convection with Downstream Reformed-V and Reformed-Double-V Generators

Withada Jedsadaratanachai,Amnart Boonloi

doi:10.3844/jmssp.2014.426.435

Abstract

Thermal assessments for laminar flow in an isothermal wall square channel over downstream Reformed-V (RV) and Reformed-Double-V (RDV) generators inserted diagonally are presented numerically in three dimensional. The RV and RDV are designed to comfort for forming and installing in the heat exchanger channel. The effect of RV and RDV height is investigated in terms of blockage ratio, b/H, BR = 0.05-0.30 for Reynolds number based on the hydraulic diameter of the square channel, Re = 100-1200. The SIMPLE algorithm, finite volume method and the periodic condition are used in the current computational domain. The mathematical results show that the uses of RV and RDV provide higher heat transfer rate than the smooth square channel with no generators. The RV gives higher on both heat transfer rate and friction factor values than the RDV case for all BR and Re values. The maximum heat transfer rate and friction factor are found around 20.5 and 420 times over the smooth square channel, respectively, at BR = 0.30 for RV case. The optimum thermal enhancement factor, TEF, is found at BR = 0.1, Re = 2000 around 2.95 for RDV case.

Highlights

The installation of the vortex generators is widely use in heat exchanger channel to improve the thermal performance
The V-shaped vortex generators are usually applied in the heat system, because it can create the impinging jet over the channel lead to the augmenting heat transfer rate and increasing the thermal performance
The flow configurations are reported in term of streamlines in transverse planes as Fig. 2, while the heat transfer characteristics are presented in forms of contour temperature in transverse planes and contours of local Nusselt number as Fig. 3 and 4, respectively

Summary

Introduction

The installation of the vortex generators is widely use in heat exchanger channel to improve the thermal performance. The gaps which decreased the thermal performance and heat transfer rate were found when using the generators placed on the channel walls. To obtain numerical solutions for the heat exchanger channel with Reformed-V (RV) and ReformedDouble-V (RDV) vortex generators

Results

Conclusion