Experimental investigation of heat transfer and pressure drop in fin-tube waste heat recovery heat exchangers

Abstract

The aim of this master thesis was to investigate heat transfer and pressure drop of fin-tube heat exchangers. Experimental investigations of heat transfer and pressure drop in fin-tube bundles has been performed. The main focus was to investigate the influence of the fin height and the fin tip clearance. The effect of the uneven heat transfer distribution on the heat transfer coefficient has been analyzed.A literature survey has been dedicated to investigate the influence of the fin height and fin tip clearance. Solid fins showed increasing heat transfer coefficient for an increase in the fin tip clearance by a reduced fin height. Serrated fins showed the opposite.Comparison of experimental results indicated that altering the fin height had most influence on the heat transfer and pressure drop of fin-tube bundles. The experimental results were compared to the literature. It showed strong correlation for the fin height adjustments. Altering the fin tip clearances by changed tube spacing had contrary results.Numerical simulations of uneven heat transfer distribution showed high deviation in the actual fin efficiency compared to the theoretical fin efficiency. Consequently, this revealed large errors in the heat transfer coefficient determination. The findings in the literature showed disagreements regarding this topic.