Heat transfer enhancement of backward-facing step flow in a channel by using baffle installation on the channel wall

Summary.

Aiming to enhance the heat transfer characteristics of backward-facing step flow in a channel, the present study proposes a method to install a baffle onto the channel wall. The effects of the dimensionless baffle height H _b , baffle thickness W _b , and distance between the backward-facing step and baffle D on the flow structure, temperature distribution and Nusselt number variation for the system at various Re and Gr/Re² are numerically investigated. Comparing the results of the cases with or without the installation of baffle, the maximum augmentation on average Nusselt number is about 190% for the heating step and 150% for the heating section of the bottom plate when Pr=0.7, H _s =0.5, L=5, H _b =0.3, W _b =0.2, 100 ≤Re ≤500 and 0≤Gr/Re²≤1. A slight movement of the baffle position could cause a drastic change in the transfer characteristics. In addition, as W _b varies from 0.2 to 0.5, the difference in the average Nusselt number is within 3%.