Airside heat transfer and pressure drop of an aluminum heat exchanger having a new louver fin with leading edge extension

Abstract

Conventional louver fins have an inherent problem of condensate drainage. In this study, a newly developed louver fin is introduced. The louver fin has an extension at leading edge. Dry and wet surface heat transfer and pressure drop characteristics of the heat exchanger made of the new fins were investigated, and results are compared with those having trailing edge extension fins or conventional fins. For conventional sample, significant differences between dry and wet j and f factors were observed. Dry j factors were 166% larger than wet j factors, and wet f factors were 68% larger than dry f factors. The discrepancies were significantly reduced for the samples having extensions, which suggests that extensions are effective in condensate control. The present sample having leading edge extension yielded higher dry j factors than the sample having trailing edge extension, probably due to proper allocation of louvers. Wet j factors of the two extended samples were approximately the same, which means that the condensate drainage is better for trailing edge extension than leading edge extension. Under dry condition, j/f1/3 of leading edge sample were 132 % and 59% higher than those of trailing edge extension and conventional sample respectively. However, under wet condition, j/f1/3 of leading edge extension sample were 87% and 205% higher than those of trailing edge extension and conventional sample. This confirms that the present leading edge extension sample shows better performance than trailing edge extension sample, both under dry and wet condition.