CONVECTIVE HEAT TRANSFER IN A CHANNEL WITH POROUS BAFFLES

Abstract

Laminar forced-convective heat transfer in a two-dimensional parallel-plate channel with 16 porous baffles mounted alternately on bottom and top walls was studied numerically. The numerical study was conducted by developing and using a finite-volume code. The pressure and velocity fields were linked by the SIMPLEC algorithm. The extended Darcy-Forchheimer model was used to describe resistance to flow through the porous baffles. The grid independence was established for the developed code. The code was validated against the studies by Sung et al. [7] and Nakayama [15]. The parametric runs were made for Reynolds numbers (Re) of 100, 200, 300, and 400; for Darcy number (Da) values of 8.783 × 10⁻⁶, 1.309 × 10⁻⁵, and 1.791 × 10^−5; for nondimensional baffle spacing values of (D∗)=11, 13, and 15; for nondimensional baffle aspect ratio (W∗) of 4, 6, and 12; thermal conductivity ratios (K∗) of 1, 10, and 100; and nondimensional baffle height (B∗) was fixed at 1/3. Consideration was given only to flow of air (Pr=0.7). It was found that heat transfer enhancement ratios for solid-baffle cases are higher than those for corresponding porous-baffle cases. The heat transfer enhancement ratio increased with increase in Re, decrease in Da, increase in K∗, increase in D∗, and decrease in W∗. The heat transfer enhancement per unit increase in pumping power was less than unity for the range of parameters considered in this study.