Effects of non-Newtonian behaviour on the thermal performance of nanofluids in a horizontal channel with discrete regions of heating and cooling

• The potential of nanofluid based power-law flow is proposed in heat exchangers.
• Flow intensity and heat transfer can be adjusted by using power-law based fluids.
• A numerical study on exchanger with discrete heating regions confirms the proposal.

A numerical simulation is performed to investigate laminar forced convection nanofluid based non-Newtonian flow in a horizontal parallel plate with discrete regions of heating and cooling. Water, pseudo-plastic and dilatant fluids are used as working base fluids. Power-law modelling is adopted to predict the effect of non-Newtonian behaviour on the thermal performance of nanofluids in a channel with heating (cooling) regions placed symmetrically on walls, and the remaining surfaces are considered adiabatic. The velocity and temperature fields, heat transfer coefficient ratio, and pressure drop are investigated, considering the influence of power-law index nn, nanoparticle volume fraction ϕϕ, Reynolds number, and generalized Prandtl number. It is observed that the velocity and temperature of nanofluids may increase or decrease considerably by changing the base power-law fluids. The results reveal that nanofluids based on dilatant flow are more sensitive to the environmental heat flux than those based on pseudo-plastic fluid. Furthermore, the pressure drop increases as the power-law index rises. The findings demonstrate that the presence of non-Newtonian effects in nanofluids can lead to improvement and optimization in the thermal performance of channels, which suggests the potential of nanofluid based power-law flow in industrial equipment heating and cooling applications.