Multi-objective optimization of thermal-hydraulic performance in a microchannel heat sink with offset ribs using the fuzzy grey approach

Abstract The effect of four geometrical parameters (width of the offset ribs, depth of the offset ribs, incline angle of the offset ribs, and distance between the adjacent offset ribs) on heat transfer enhancement, friction loss, and performance evaluation criteria is analyzed on the basis of the orthogonal experimental design (OED) method and fuzzy grey relational analysis (FGRA). Results of FGRA reveals that depth is the most influential factor in heat transfer enhancement, width affects the friction loss more than others, whereas incline angle is the most significant factor in the performance evaluation criteria (PEC) of microchannel heat sink (MHS). A series of S-shaped staggered triangular offset ribs (SSTOR) is proposed to strengthen the performance of MHS based on the results of FGRA. The MHSs with novel offset ribs are studied at different Reynolds numbers from 100 to 1000 to find the optimal offset ribs. The average Nusselt number, pressure drop, PEC, and maximum temperature at the bottom wall of the MHS with five different novel offset ribs are discussed. The result shows that the optimal offset rib structure, SSTOR-45, can significantly improve the behavior of MHS with PEC = 1.36 at Re = 1000. Furthermore, this work offers an excellent reference for MHS design in the electronic package heat dissipation field.