Numerical optimization and experimental study of helically coiled tube heat exchanger based on Entransy degeneration theory

Heat exchangers are the most frequent energy transfer equipment in energy-consuming sectors, and their design and optimization are critical for reducing environmental impact and energy waste. In this study, a thermodynamic model of a spiral coil heat exchanger is reconstructed, and the use of Entrancy degradation theory is reviewed. The idea of layered modeling of helically coiled tube heat exchanger and the double-layer cycle model with simultaneous optimization of structural parameters and flow conditions are proposed, and experiments are performed to verify the reliability of the numerical model through. Multi-objective genetic algorithm is adopted for optimization with Entransy degeneration number (N-gHE), Performance Evaluation Criteria (PEC) and Field Synergy Number (Fc) as optimization criteria to achieve multi-layer structure, multi-layer cycle and multi-objective optimization. The correlation equations for flow and heat transfer in the tube and shell sides of the heat exchanger are obtained, which are explored and verified. The results show that the heat exchanger thermodynamic modification model and the derived Entransy degeneration optimization criterion for the heat exchanger can reduce the overall useful energy loss by 11.2 % similar to 15.2 %. When the minimum N-gHE is taken as the optimization criterion, the NgHE is reduced by 13.6 % compared to the PEC and by 12.2 % compared to the Fc.