Heat Transfer Deterioration by the Copper Oxide Layer on Horizontal Subcooled Flow Boiling

Water-copper is one of the most common combinations of working fluid and heating surface in high-performance cooling systems. Copper is usually selected for its high thermal conductivity and water for its high heat transfer coefficient, especially in the two-phase regime. However, copper tends to suffer oxidation in the presence of water and thus the heat flux performance is affected. In this research, an experimental investigation was conducted using a cooper bare surface as a heating surface under a constant mass flux of 600 kg center dot m-2 center dot s-1 of deionized water at a subcooled inlet temperature Delta Tsub of 70 K under atmospheric pressure conditions on a closed-loop. To confirm the heat transfer deterioration, the experiment was repeated thirteen times. On the flow boiling region after thirteen experiments, the results show an increase in the wall superheat Delta Tsat of approximately 26% and a reduction in the heat flux of approximately 200 kW center dot m-2. On the other hand, the effect of oxidation on the single phase is almost marginal.