EXPERIMENTAL INVESTIGATION OF CHF ENH ANCEMENT USING NANOFLUIDS (CuO) IN SUBCOOLED POOL BOILING

Transferring a large amount of energy to/from a system has always been a challenge in cooling/heat ing systems as well as power cycles and refriger ants. Boiling phenomena is a key method for re moving the heat from the high heat flux mediums and surfaces. Thus, specific attention should be dedicated to the enhancement of heat transfer coef ficient. Nano - fluid is an engineered colloidal suspension of nano - sized particles in a base fluid, such as water or glycols, which provides special heat transfer features, such as enhancement of thermal conductivity and changing of the heat transfer surfac e due to scale formation. It literally has best of both worlds cause we can use the heat transfer fluid as a liquid with added benefits of solid dispersed in it. Stable nanofluid was prepared with CuO nanoparticles (30 - 50 nm in diameter) and deionized water. The microscopic morphology of the nanoparticle deposition layer at the heated surface was characterized by SEM images. It seems that the deposition layers can modify the morphology, but it also del ays the detachment of small bubbles from the heated surface. The effect of geometry and bulk temperature was also studied. A comparative experiment indicates that critical heat flux improved with increase in nanoparticles concentration. In the same fashio n, the secondary objective is to give effective surface roughness on CHF by adding different concentrations of copper oxide nanoparticle.