A NUMERICAL STUDY OF NANOFLUID FORCED CONVECTION IN A POROUS CHANNEL WITH DISCRETE HEAT SOURCES

Abstract

A numerical simulation is carried out to investigate the laminar forced convection flow of Al2O3−water nanofluid in a porous parallel plates channel with discrete heat sources using a single-phase approach. The heat sources are placed on the bottom wall of the channel, and the remaining surfaces of the channel are considered adiabatic. The effects of Darcy number (Da = 10−1, 10−2, 10−4, and 10−6), particle volume fraction (φ = 0% (distilled water), 3%, 5%, and 9%), heat flux of heat sources (q = 5000,10,000, 20,000, and 30,000 W/m2), porosity (0.4, 0.6, 0.8, and 0.95), and thermal conductivity ratio (ks/kf = 1, 5,10, and 30) on the average heat transfer coefficient (h), pressure drop (ΔP), thermal-hydraulic performance (η), and wall temperature (Tw) are investigated. A remarkable decrease in wall temperature is observed, especially on the heat sources. It is founded that heat transfer and pressure drop increase for all cases as volume fraction increases. Results also reveal that in a fixed volume fraction, the average heat transfer coefficient ratio, referring to the values calculated for base fluid, increases as heat flux and porosity increase or thermal conductivity ratio decreases. No change in the average heat transfer coefficient ratio is observed with Darcy number variation. Furthermore, it is found that the pressure ratio, referring to the values calculated for base fluid, is approximately independent of all considered parameters, except volume fraction.