Effects of key thermal parameters on the flow boiling process of water and prediction of the heat transfer coefficient in the corrugated plate heat exchanger

Abstract

The thermal parameters of the corrugated plate heat exchanger (CPHE) significantly affect its flow and heat transfer performance. To investigate the influence of key thermal parameters on the flow boiling process of water in CPHE, this study established a three-dimensional numerical model based on the VOF model and Lee evaporation model. The Nusselt number and heat transfer coefficient were calculated, and the simulation results were validated with experimental results showing an error of less than 5 %. The key flow and heat/mass transfer parameters of different height sections and the entire fluid domain were simultaneously calculated. The effects of wall superheat (5.0–12.5 K), inlet subcooling (−5.0–0 K), and inlet velocity (0.4–0.8 m/s) on pressure drop, mass transfer rate, heat transfer coefficient, etc. were analyzed. The main conclusions are as follows: the two-phase pressure drop mainly depends on the flow rate and the gas-liquid volume fraction. The mass transfer rate has a positive correlation with the superheat, and a negative correlation with the subcooling degree and the flow rate. Velocity affects the heat transfer coefficient more easily than superheat and inlet velocity. When the inlet flow rate is 0.8 m/s, the heat transfer coefficient is 23.23 kW/(m² K), which is 12.00 kW/(m² K) higher than that when the inlet flow rate is 0.4 m/s, about 106.78 %. This study presents a novel correlation that can precisely predict the heat transfer coefficient in the flow boiling process within a specific range, with an average prediction error of merely 6.71 % and a correlation coefficient of 0.98. The research findings are beneficial for the thermal design and heat-mass transfer enhancement of heat exchangers with phase change processes.