Abstract: The effect of fin spacing on the heat transfer performance and pressure drop of fin and tube heat exchangers is studied in this paper. At present, the fin spacing of 5mm diameter is usually between 1.2mm and 1.3mm. The fin spacing can be reduced to 0.8mm to 1.0mm by means of compact design and machining. This paper mainly analyzes and compares the influence of fin pitch reduction on heat transfer capability and air pressure loss from theoretical analysis, three-dimensional modeling and fluent calculation. Under the same windward area and wind speed, with the decrease of fin spacing, the capacity increases gradually, but the pressure loss and power increase at the same time. It shows that the problem of air loss caused by fin infilling must be solved at the same time when the fin spacing decreases, effectively analyze the influence of contact thermal resistance. Otherwise, the heat transfer area can’t be fully utilized. This study can provide some references for fin design of heat exchangers.

Key words: Fin distance, Finned tube heat exchanger, Compact design method, Heat transfer performance, Air pressure loss