Performance evaluation and optimization of flattened microchannel heat sinks for the electronic cooling application

The present study introduces a microchannel heat sink (MCHS) with a new geometry entitled as flattened , which is used to dissipate heat flux form high heat flux generation devices and evaluates its hydrothermal performance. Three-dimensional conjugate heat transfer problem with the assumptions of laminar and steady-state fluid flow has been solved numerically, based on finite volume method. Silicon and pure water with temperature-independent thermophysical properties form the solid part of the heat sink and the coolant, respectively. The performance of three geometric designs of flattened cross-sectional MCHS including a simple single-layer heat sink (Design-A), a heat sink with an adjustable horizontal separation plate (Design-B), and a double-layer MCHS with truncated upper channels (Design-C), is evaluated based on the changes of six effective parameters in the problem including the number of microchannels ( N ), wall thickness ( W w ), thickness of the separation plate ( δ ), vertical position of the separation plate ( H 1 ), velocity ratio ( V R ), and the length ratio ( L R ), and under the thermal and hydrodynamic conditions of a uniform heat flux and four different pumping powers. Creating the lowest thermal resistance and the most uniform temperature distribution are the criteria for selecting the optimal designs. The results show that Design-C with the specifications of N = 72, W w = 56 µm, δ = 25 µm, H 1 = 300 µm, V R = 0.7, and L R = 0.7 has the best performance among the all cases by creating the thermal resistance of 0.1333 kW −1 , which also indicates a 7.9 % performance improvement over similar studies.