The multi-louver fin is the primary geometric configuration used to enhance the air-side heat transfer characteristics of automotive heat exchangers today. This work presents an investigation into the effects of multi-louver fins on the air-side Stanton number (St) and Fanning friction factor (f) characteristics of a heat exchanger. Experimental St data ranging between 0.0095 and 0.065 and/ data ranging between 0.04 and 0.55 are reported for louver pitch based Reynolds numbers ranging between 30 and 4000. Brazed core test samples with multi-louver fins are utilized to complete this study. Previous investigators have correlated the air-side St and/ to geometric parameters such as fin height, fin pitch, louver pitch, louver angle and louver length along with flow efficiency and Reynolds number. An example of the range of parameters tested by previous investigators is fin pitch to louver pitch ratio which ranged between 1.65 and 4.1 compared to the range of 2.1 to 5.3 in this work. In general, wider ranges of each parameter than those tested by previous investigators were chosen to produce a more robust correlation. Three new forms of St correlations are derived which can predict heat transfer more accurately than the forms previously derived in the literature. The average percent deviation was improved from -24.37% and +2.10% to +0.59% with the standard deviation of the deviations improved from 1 1.43% and 15.04% to 8.95%. This provided a St correlation which would predict the heat transfer of a heat exchanger to within 3% for 60% of the data or to within 9% for 99% of the data. The correlations of Cowell and Achaichia were modified by the author predict/more accurately than any form examined in this work. The average percent deviation was improved from +12.19% and -23.59% to +0.75% and -0.19% with the standard deviation of the deviations improved from 53.89% to 12.72% for one correlation and maintained around 11 % for the other.
Library of Congress Subject Headings
Heat exchangers; Radiators; Heat--Transmission
Department, Program, or Center
Mechanical Engineering (KGCOE)
Fix, Patrick, "An Investigation of air side heat transfer enhancement in multi-louver fins within automotive compact heat exchangers" (1996). Thesis. Rochester Institute of Technology. Accessed from
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