Modeling and optimization of the thermal-hydraulic performance of direct contact heat exchanger using quasi-opposite Jaya algorithm

In this study, the thermal-hydraulic performance of a direct contact heat exchanger (DCHE) was explored and optimized by applying the multi-objective quasi-opposite Jaya (MOQO-Jaya) algorithm. Inlet temperature of the continuous phase, continuous phase flow rate, dispersed phase flow rate, evaporator height, nozzle diameter, and number of jets were considered as the design variables for the optimization. The optimization functions were the volumetric heat transfer coefficient (VHTC), entransy dissipation, and entropy production. Study results indicated that the entransy dissipation and entropy production were negatively correlated with the heat transfer capacity in a DCHE, with a Pearson correlation coefficient above 0.96; that is, the smaller the entransy dissipation and entropy production, the better the heat transfer performance in the DCHE. The sensitivity of design parameters demonstrated that temperature played an important role. The optimization results and performance of the MOQO-Jaya algorithm were compared with those of the non-dominated sorting genetic algorithm (NSGA-II). The convergence of MOQO-Jaya was 2.24 times quicker than that of NSGA-II in DCHE optimization. The correctness of numerical model for optimizing the DCHE was verified through experiments. The errors of the experimental and algorithm optimizations both were within ±10%. Results demonstrated that after multi-objective optimization, the VHTC increased by 33.89% and entransy dissipation reduced by 44%, compared with those of traditional experiments.