Multi-Objective Design Optimization of Multi-Floor, Counterflow Micro Heat Exchangers

Abstract

Heat removal capacity, coolant pumping pressure drop and surface temperature non-uniformity are three major challenges facing single-phase flow microchannel compact heat exchangers. In this paper multi-objective optimization has been performed to increase heat removal capacity, and decrease pressure drop and temperature non-uniformity in single-flow microchannels. Three-dimensional (3D) 4-floor branching networks have been applied to increase heat removal capacity of a microchannel from silicon substrate (15×15×2 mm). Each floor has four different branching sub-networks with opposite flow direction with respect to the next one. Each branching network has four inlets and one outlet. However, branching patterns of each of these sub-networks could be different from the others. Conjugate heat transfer analysis has been performed by developing a software package which uses quasi-1D thermo-fluid analysis and a 3D steady heat conduction analysis. These two solvers are coupled through their common boundaries representing surfaces of the cooling microchannels. Using quasi-1D solver significantly decreases computing time and its results are in good agreement with 3D Navier-Stokes equations solver for these types of application. The analysis package is capable of generating 3D branching networks with random topologies. 1341 random cooling networks were simulated using this analysis package. Multi-objective optimization using modeFrontier software was performed using response surface approximation and genetic algorithm. Diameters and branching pattern of each sub-network and coolant flow direction on each floor were design variables of multi-objective optimization. Maximizing heat removal capacity, minimizing pressure drop and temperature non-uniformity on the hot surface were three simultaneous objectives of the optimization. Pareto-optimal solutions demonstrate that thermal loads of up to 500 W/cm2 can be managed with 3D 4-floor microchannel cooling networks.

Optimized Multi-Floor Throughflow Micro Heat Exchangers

“…Multi-objective Genetic Algorithm II (NSGA-II) developed by Deb et al [24,25], was chosen to perform optimization. The four simultaneous objectives of the optimization study were: 1) Maximize total heat removed, 2) Minimize total pressure drop, 3) Minimize temperature non-uniformity on hot surface 4) Minimize temperature on hot surface Abdoli and Dulikravich [14] demonstrated that Gaussian Radial Basis Function (GRBF) method gives more accurate results in comparison to other response surface methods. Then, this GRBF was coupled to NSGA-II multi-objective optimization algorithm in modeFRONTIER software in order to perform the optimization.…”

“…Husain and Kim [13] performed single objective optimization using response surface approximation in order to find optimal microchannel width, depth, and fin width. Abdoli and Dulikravich [14] performed multi objective optimization for 4-floor branching microchannel configurations with 67 design variables in order to improve heat removal and decrease temperature nonuniformity and coolant pumping pressure drop. There is still a need for more research on single-phase flow microchannels in order to increase heat transfer efficiency and decrease temperature non-uniformity and pressure drop [15].…”

“…This work represents a significant improvement over the effort [16,14] to develop high efficiency compact heat exchangers based on optimally branched networks of microchannels.…”

Multi-Objective Optimization of Micro Pin-Fin Arrays for Cooling of High Heat Flux Electronics

“…In previous optimization work, Jelisavcic et al [6] and Gonzales et al [7] found an optimum configuration of network of cooling passages. Abdoli and Dulikravich [8,9,10,11] also optimized multi-floor microchannel configurations. Fabbri and Dhir [12] optimized an array of microjet for cooling of high performance electronics.…”