NUMERICAL SIMULATION OF FIN PATTERNS ON AIR-SIDE HEAT TRANSFER AND FLOW FRICTION CHARACTERISTICS OF FIN-AND-TUBE HEAT EXCHANGERS

摘要

Three-dimensional numerical simulations of air-side heat transfer and flow friction characteristics of 6-row fin-and-tube heat exchangers with various types of fin patterns have been conducted by the standard k e - model with standard wall function. Five types of fin are studied, that is, plain fin, slit fin, vortex-generator fin, first mixed fin (front 3-row vortexgenerator fin and rear 3-row slit fin) and second mixed fin (front 3-row slit fin and rear 3-row vortex-generator fin). Results show that slit fin provides higher heat transfer and pressure drop than the other four fins, and plain fin provides the lowest heat transfer and pressure drop with Reynolds numbers ranging from 4000 to 8000. The air-side performances of heat exchangers with five types of fin have been evaluated under three criteria and the results show that under identical mass flow rate criteria, identical pumping power criteria and identical pressure drop criteria, first mixed fin offers better heat transfer performance than slit fin. Under identical mass flow rate criteria, vortex-generator fin provides better performance than second mixed fin when Re is less than about 5100, while when Re is larger than about 5100, second mixed fin provides better performance than vortex-generator fin. Under identical pumping power criteria and identical pressure drop criteria, vortex-generator fin almost offers the best heat transfer performance, while second mixed fin offers the worst performance.