The single-blow transient testing technique for offset and wavy fins of compact plate-fin heat exchangers

Abstract

A single-blow transient test technique is employed to measure the Colburn j factor versus Reynolds number characteristics of high efficiency compact heat exchanger surfaces having offset and wavy fins. Using the experimental data, the NTU values are estimated for 5 types of fins. The measured data is evaluated using the maximum slope method to obtain the corresponding heat transfer coefficient in terms of Colburn j factor, and then is compared with the available correlations of theoretical steady state CFD model. In this analysis, the effects of non-adiabatic side walls and longitudinal heat conduction on the exit fluid temperature response and NTU values are discussed. The test core pressure drops are also measured, and the pressure drop components of entrance, acceleration, core friction and exit losses are compared with the CFD results.