|
Spray cooling has been considered as one of the most efficient alternatives for the removal of high heat fluxes and is currently used in several modern industrial and technological applications to dissipate high amounts of heat from their components such as in electronics, lasers, metallurgical, and nuclear. In many of these applications steady-state high heat fluxes (SSHHF) removal is required. In this research, experiments were conducted to determine parameters that affect the steady-state behavior of high heat fluxes when using spray cooling. The parameters taken in consideration included the mass flow rate, the heated surface roughness, the liquid subcooling temperature, and the spray angle. Water was used as the working fluid in the experiments. An experimental apparatus was built to carry- out the experiments, consisting of a copper heater with a disc shaped surface, an atomizer system that used commercial nozzles, and a data acquisition systems to accurately measure temperatures, heat fluxes, flow rates, and room conditions. The commercial nozzles generated mean droplet diameters ranging from 85 to 100 micrometers and flow rates between 1.48 and 1.9L/hr. Two surface conditions were sued; one polished with 0.25 micrometers liquid solution and the other polished with 600 grit silicon carbide grinding paper. The SSHHF was determined by observing the transient response of the surface temperature and the surface heat flux. Steady- state heat fluxes in the order of 100W/cm2 were obtained in most cases. Results indicated that higher SSHHF can be obtained with increasing mass flow rates and it was easier to achieve them with smooth surfaces. Results also showed that subcooling may not be significant when high mass flow rates. Curves indicating maximum SSHHF were generated as function of the parameters investigated.
|
