Topology Optimization of Discontinuous Fin-Based Microchannel Heat Exchangers

Abstract The article provides the development of a multiobjective optimization function for designing discontinuous plate-fin microchannel heat exchangers (PFMCHEs). Stagnation pressure energy, thermal energy gain, and entropy generation serve as multiobjective functions. A penalization factor controls the distribution of solid and fluid domains to accommodate the variability in shape variations to arrive at trade-offs between competing goals of the objective functions. Penalization factor is incorporated into the framework of governing equations to capture the relative solid and fluid regions in the design domain. The set of governing equations coupled with an optimization algorithm is solved using a generalized computational fluid dynamics solver to arrive at a multitude of feasible heat exchanger designs. The framework relies on a finite volume formulation to arrive at converged temperature, velocity, and pressure fields, while the optimization framework provides a trade-off among the competing performance indicators. The efficacy of the model is evaluated on a single plate of PFMCHE comprising a rectangular fin, wherein the variability in performance is examined based on weighing parameters of the objective function. The model provides variable fin shapes featuring efficient thermal energy transfer with minimal pressure drop and entropy generation. The results indicate that the length of fins is more pronounced at the center of PFMCHE, leading to a 30–35% reduction in pressure drop and entropy generation relative to the initial design. Pressure drop and entropy generation are preferred objective functions over heat transfer for generating robust heat exchanger designs.