34 Heat Transfer and Pressure Drop Correlations for Compact Heat Exchangers with Multi-Region Louver Fins

An experimental study on the air-side heat transfer and pressure drop characteristics for brazed aluminum heat exchangers with multi-region louver fins and flat tubes was conducted. Multi-region louver fin is a new type fin on which there are more louver regions than that on current fin on which there are two louver regions. Series of tests were conducted for seven kinds of heat exchangers with different numbers of louver regions (0–6) and fin louver height at the air-side Reynolds numbers of 400–1600 based on the louver pitch. The air-side thermal performance data were analyzed by using the effectiveness-NTU method for cross-flow heat exchangers at unmixed fluid conditions. Characteristics of the heat transfer and pressure drop for heat exchangers with different geometry parameters were presented in terms of Colburn j-factor and Fanning friction f-factor as function of Reynolds number. The general correlations for j and f factors were developed by regression method.