EXPERIMENTAL AND NUMERICAL STUDIES ON THE THERMAL CONI ACT RESISTANCE OF A FIN TUBE HEAT EXCHANGER

This work presents the investigation of the !henna! contact resistance in a fin-tube
heat exchanger. Experiments and numerical simulations were conducted to understand
the mechanism of thennal contact resistance between the tins and the tubes. Heat
transfer and pressure drop experiments for 9.52 mm fin-tube heat exchangers were
conducted in a vacuum chamber with water-to-water, steady state loop for different
bullet expansion ratios from 1.046 to 1.059. The heat imbalance of the experiments
was kept within 3%.The overall electrical resistance of a fin-tube heat exchanger for
each bullet expansion ratio was also obtained by electrical measurements and
compared with the thermal measurements. An analogy of the electrical and thennal
shape factor was investigated by experiment and numerical simulation to obtain an
appropriate tin shape factor.