Thermo-hydraulic transport characteristics of non-Newtonian fluid flows through corrugated channels

Abstract

The present study investigates numerically the thermo-hydraulic transport characteristics of non-Newtonian fluids in corrugated channels. The power-law model is used to describe the constitutive behavior of the non-Newtonian fluid. The results indicate that the enhancement in heat transfer for corrugated channels over equivalent straight channel is not significant for smaller amplitude of the wall waviness of the channel, while there is a significant enhancement for the higher amplitude. The rate of enhancement with respect to equivalent straight channel decreases with increase in power law index and the decrement is more prominent for shear thinning fluids and for higher values of Reynolds number. Furthermore, an estimation of pressure drop for flow through the corrugated and equivalent straight channels has been made to compare the values against the enhancement in heat transfer rate. It reveals that the ratio of pressure drop (Δp/Δpstraight) is more as compared to the enhancement in heat transfer (Nu¯/Nu¯straight) for all the parameters considered in the present work. It further reveals that the use of shear thinning fluids is more suitable for the purpose of maximum heat transfer augmentation with minimum pressure drop. The results obtained from our studies may have significant consequences on the selection of wavy channel geometry configuration for compact heat exchanger handling non-Newtonian fluids towards a cost effective process of heat transfer.