Heat and mass transfer performance of low Reynolds number flow behind a cylinder connecting with an L-shaped flexible body within a microchannel

Abstract

In order to enhance the heat and mass transfer performance of laminar flow within a microchannel at a low Reynolds number, this paper introduces an asymmetric structure of an L-shaped flexible body connecting to a cylinder into the microchannel and studies the effects of the geometric dimensions of the L-shaped flexible body on the flow pattern transition and the heat and mass transfer performance, including the pressure loss, the Nusselt number, and the outlet mixing efficiency. It is found that by means of an asymmetric structure of the L-shaped flexible body connecting to the cylinder, the flow pattern transitions from laminar flow to vortex flow at a low Reynolds number based on the diameter of the cylinder of Red = 25. The transition of the flow patterns induced by an asymmetric L-shaped flexible body enhances the thermal and mixing performance of the fluid flow within the microchannel. Both the Nusselt number and the outlet mixing efficiency significantly increase under the influence of the L-shaped flexible body compared to the case with a single cylinder, and they increase with the increasing length of the vertical part of the L-shaped flexible body. The findings in the present work provide a new strategy to enhance the heat and mass transfer performance of low-Reynolds-number fluid flow within a microchannel by using the interaction of an asymmetric flexible body with the fluid flow behind a bluff body.