Heat transfer and flow characteristics of forced convection in PDMS microchannel heat sink

Abstract

Recently, microfluidic devices are being widely used in various heat transfer applications and, thermal management in microchannels is a challenging issue. As a solution, different types of microchannel heat sinks have been employed to enhance the heat transfer. The flow characteristics in the microchannel heat sink have influence on the heat transfer rate and thermal management performance. Therefore, the simultaneous measurement of temperature and velocity fields is highly required to understand the single-phase heat transfer phenomena in the PDMS microchannel heat sink. In this study, μPIV-μLIF technique which can provide the velocity and temperature field information of micro-scale thermofluid flow was newly developed to analyze the heat transfer of forced convection in PDMS microchannel heat sink. Especially, flow characteristics in the microchannel heat sink were systematically investigated. At a high Re flow (Re = 10) with heating, a high-speed crossflow occurs in the microchannel heat sink. Spanwise vorticity and Reynolds shear stress, which contribute to heat transfer in the microchannel, exhibit higher values at Re = 10 with heating compared to the non-heating case. Variations in velocity and local Nu number were also compared to explain heat transfer enhancement in the microchannel heat sink. Temporal variations in the temperature field were evaluated to demonstrate the effect of flow on heat transfer. The results presented herein would be helpful for understanding heat transfer in microscale thermofluid flows and for designing microscale heat transfer devices.