Numerical Investigation of Flow Dynamics and Heat Transfer Characteristics in a Microchannel Heat Sink

Microchannel heat sinks are widely used in dissipation of large amounts of heat from a small area. In this study, a three-dimensional numerical simulation is performed in order to investigate the flow dynamics and heat transfer characteristics in a microchannel heat sink. A unit cell containing a single microchannel of a width of 231 μm and a depth of 713 μm with surrounding solid is used for simulation. Water at 15 °C is used as the cooling liquid with Reynolds number ranging from 225 to 1450 and a constant heat flux is applied at the bottom of the heat sink. A commercial CFD code employing finite element method is used for the numerical simulation. Mesh independence test is performed for the accuracy of results. The pressure drop in the microchannel obtained from the simulation agrees well with experimental results. The highest temperature is found at the bottom of the heat sink immediately below the channel outlet and the lowest is at the channel inlet. The heat flux is high near the channel inlet due to thin thermal boundary layer in the developing region and varies around the channel periphery with lower values at the corners. These findings demonstrate that the conventional Navier–Stokes and energy equations can adequately predict the fluid flow and heat transfer characteristics of microchannel heat sinks.