Effect of Maximum Temperature and Heating-Cooling Repeated Cycles on Thermal Contact Resistance of a Composite Tube
Experimental research results of the operational parameter effect on Thermal Contact Resistance (TCR) in a copper-aluminum L-type finned tube are presented. The investigated operational parameters were the maximum operational temperature and the number of repeated heating-cooling cycles. The TCR was experimentally determined by measuring the total heat supply, core tube wall and inner fin surface temperatures for steady-state and natural-convection conditions. In addition, the specimen was tested through up to 200 heating-cooling cycles. The experimental results showed a TCR increase of 81% at the same time as the average temperature difference between the hot inner flow and cooling air increased from 30°C to 130°C; over the maximum operational temperature (120°C), the TCR increased faster than before; and, after the heating-cooling cycle testing the TCR presented an increase of 31% in respect with the initial value. Such findings may be useful as a reference for preliminary thermal design and as recommendations for optimal operation of heat exchangers based on copper-aluminum L-type finned tubes.
G. Urriolagoitia-Calderón, L. H. Hernández-Gómez and M. Toledo-Velázquez
I. Carvajal-Mariscal et al., "Effect of Maximum Temperature and Heating-Cooling Repeated Cycles on Thermal Contact Resistance of a Composite Tube", Applied Mechanics and Materials, Vol. 15, pp. 41-46, 2009