CFD Simulation and Thermal Performance Optimization of a Helical Coil Heat Exchanger in a Heating Furnace

Based on the Fluent numerical simulation method, this study systematically analyzed the structural parameters of the spiral tube heat exchanger and the influence of the external baffle on its heat transfer performance. The results show that when the equivalent diameter of the spiral tube increased from 16.68 to 21.23 mm, its surface heat transfer coefficient decreased from 22,040 to 17,230 W/m²·K, and the outlet air temperature dropped from 822.3 to 807.3 K. However, the pressure loss decreased from 2.692 to 0.958 kPa. which reveals the contradiction between the heat transfer efficiency and the flow resistance. By adding a baffle to enhance the turbulent disturbance, the wall heat flux density is increased by 21.17%, the surface heat transfer coefficient is increased by 12.1%, and the outlet temperature is optimized, which verifies the significant improvement of the heat transfer performance by the countercurrent design. Comprehensive research shows that the collaborative optimization of spiral tube equivalent diameter parameters and baffle flow control is the key to improve the comprehensive performance of heat exchanger. The research results provide a theoretical basis for energy-saving design of industrial heat exchangers.