Experimental and Numerical Studies on Plate Fin Heat Exchanger

Abstract

In the cryogenics field, high effectiveness heat exchangers of the order of 0.96 or higher are widely used for preserving the refrigeration effect produced. So, there will be no liquid yield if the effectiveness falls below that of the design value. Due to high effectiveness, low weight & compactness, the compact heat exchangers have their extensive applications in the air-conditioning system, oil industries, food industries & in the process industries. The plate fin heat exchangers (PFHE) is a type of compact heat exchanger which is manufactured by brazing a stack of alternate plates (parting sheets) & corrugated fins together. The exchange of heat occurs by the streams through the fins. Generally, aluminium is used for manufacturing PFHE due to their high thermal conductivity & low cost. In the plate fin heat exchanger, the pressure drop is also measured along with the effectiveness. The increase in pressure gradient can be outweighed by decreasing the passage length so that an acceptable pressure drop can be achieved. There is enormous research is going on to make out the heat transfer phenomena & also to determine the dimensionless heat transfer coefficients those are the Colburn factor (j) and the friction factor (f). This thesis on the offset strip plate fin heat exchanger compares the effectiveness, overall thermal conductance & the pressure drop obtained from the experimental data with some correlations on plate fin heat exchanger i.e., Joshi-Webb correlation, Maiti-Sarangi correlation, Manglik-Bergles correlation and also with the numerically achieved data obtained by using CFD.