Cooling of a discrete heat source inside a horizontal channel linked with a composite open-cavity or protrusion

Abstract

This study is a numerical investigation of the influence of using improved channel-cavity or channel-protrusion architectures on the augmentation of convection heat transfer and pressure drop. The effect of cavity depth $H_c\in [-1,0]$ and protrusion height $H_c\in [0,0.75]$ are investigated at various Reynolds number $\text{Re}=10,40,100$ and Richardson number $\text{Ri}=0.1,1,5,10$. The governing equations are discretised and solved computationally employing the spectral-element method. The results show that the effect of the protrusion on the trend of Nusselt number is greater than the effect of the cavity. It is found that the existence of the cavity linked with the channel decreases substantially the heat transfer comparing with the smooth channel. However, the presence of the protrusion is found to increase significantly the heat transfer for all Reynolds and Richardson numbers. It is also found that in the channel-cavity flow, the pressure distribution along the channel is unaffected by the cavity height, excepting in the cavity zone. Nevertheless, the protrusion height increases significantly the pressure drop within the channel.