Numerical studies of heat transfer enhancement by cross-cut flow control in wavy fin heat exchangers

摘要

Heat transfer enhancement by cross-cut induced flow control in a wavy fin heat exchanger was studied numerically. The concept of cross-cut is cutting fin in a direction perpendicular to the flow direction. A two-dimensional five-waved wavy fin with corrugation angle 20° was used as the geometry for simulation and the cross-cut was applied at the 3rd wave only. The simulation was performed using non dimensional governing equations for a steady laminar flow. The parametric study was conducted to find the optimum position and length of the cross-cut. The results showed that the heat transfer performance of optimized cross-cut wavy fin was enhanced by a maximum of 23.81 % greater than a typical wavy fin. The pressure drop also increased by a maximum 7.04% in optimized case. Generally, the heat transfer performance of cross-cut applied plain fin has an enhanced heat transfer performance because of the thermal boundary layer disturbance and block of longitudinal heat transfer. In the case of the cross-cut applied wavy fin, additional heat transfer enhancement can be found because the cross-cut induced flow control makes a relatively low temperature fluid at the middle of internal flow attached to the fin wall after the cross-cut region.