Heat transfer and pressure drop characteristics of wet air flow in metal foam under dehumidifying conditions

Abstract

In order to know the possibility of applying metal foam to improve performance of air conditioners, heat transfer and pressure drop characteristics of wet air flow in metal foam under air conditioning conditions were experimentally investigated and compared with those of a louvered fin-and-tube heat exchanger with the same volume. The experimental conditions cover the inlet air velocity from 0.5 to 2 m⋅s−1, Reynolds number from 100 to 500, air temperature from 27 to 32 °C, relative humidity from 50% to 90%, and PPI (numbers of pores per inch) of metal foam from 5 to 15. The research results show that, as the relative humidity of inlet air increases, both the total heat transfer rate and pressure drop in metal foam increase, and the maximal increments are 67%and 62%, respectively; with the increase of metal foam PPI, the heat transfer rate initially decreases slightly and then increases; the heat transfer capacity of copper foam heat exchanger is enhanced by 56% ~ 196% compared to that of the fin-and-tube heat exchanger.