Optimization of a microchannel heat sink using entropy minimization and genetic aggregation algorithm

•Microchannel heat sink was numerically optimized.•Heat sink optimal geometry was found applying Entropy Generation Minimization method.•Entropy generation characteristics were found applying genetic aggregation algorithm.•Over 35% reduction of irreversibility losses achieved for optimal heat sink.•Reduction of maximum temperature of LDA by 9 K achieved for optimal heat sink. A copper heat sink with rectangular U-shaped microchannels for cooling high power laser diode arrays was numerically optimised. The control volume method based commercial software was applied for solving heat transfer and fluid flow in the considered device. The optimisation procedure included over 130 various geometrical configurations with five independent geometric parameters. The Entropy Generation Minimization criterion was applied to find the optimal geometric structure. Some relations between geometrical parameters of the microchannel heat sink were analysed through statistical studies and two most important ones, i.e., the relative height (α) and width (β) of a single microchannel, were selected. Using the genetic aggregation, the entropy generation characteristics were determined as a function of α and β as well as mass flow rate of cooling medium (Ġ). The most optimal from the second law of thermodynamics point of view configuration was the one with αopt = 0.86, βopt = 0.347 and Ġ = 0.00183 kg/s. Comparing with the initial geometry, over 35% reduction of irreversibility losses for the optimal heat sink had been achieved, i.e., heat sink thermodynamic efficiency increases from 90.05% to 91.8%, while maximum temperature of cooled semiconductor element was reduced from 333.3 K to 324.2 K.