Implication of geometrical configuration on heat transfer enhancement in converging minichannel using nanofluid by two phase mixture model: A numerical analysis

Abstract

In the present study laminar forced convective flow of nanofluid through a converging minichannel is investigated numerically by employing two phase mixture model. The heat transfer enhancement and the corresponding pressure drop are analyzed for the following range of parameters: Reynolds number (700 ≤ Re ≤ 1650), particle volume concentration (0% ≤ ϕ ≤ 4%) and converging angle (θ = 0.029°, 0.043° and 0.05°). The results indicate that there is a considerable increase in pressure drop coupled with enhancement in heat transfer rate with particle loading due to the improvement in the thermal properties of the resulting mixture. The pressure drop in the converging channel increases with the converging angle. The pressure drop augments as high as 2 times by advancing the particle loading from 0% to 4%. The wall temperature decreases appreciably by 34 K and heat transfer coefficient is enhanced by as high as 98% from Re =  700, ϕ = 0% and straight channel to Re =1650, Hout = 2.75mm and ϕ = 4%. The enhancement in heat transfer and corresponding increase in pressure drop as compared to equivalent straight channel is presented by the performance factor, which increases with decrease in converging angle. There is a significant concern of the pumping power with increase in converging angle, volume fraction and Reynolds number.