The effect of grooved surfaces on pool boiling heat transfer of water and Fe3O4/water nanofluid

Investigating of boiling process is one of the attractive fields for researchers, because of many applications in industry such as heat exchangers and air condition systems. One of the important and effective factors in pool boiling heat transfer is the heating surface geometry. In present article, pool boiling of dionized water and Fe3O4/water nanofluid at atmospheric pressure have been analyzed on smooth and grooved copper surfaces, experimentally. The effect of rectangular, circular and triangular grooves with the same pitch on boiling heat transfer is the main aim of present article. The results have showed that the boiling heat transfer coefficient of dionized water in circular and rectangular grooved surfaces has enhanced 92% and 48.9%, respectively, and has reduced 33.1% in triangular grooved surface toward the smooth surface. Also, the boiling heat transfer coefficient of Fe3O4/water nanofluid in circular grooved surfaces has increased 40.7% and has decreased 21.8% and 88.7% in rectangular and triangular grooved surfaces, respectively, toward the smooth surface. The corners existence in rectangular and triangular geometries causes thermal resistance increasing and heat transfer coefficient decreasing toward circular geometry. Also, the groove area, the mechanism of bubbles creation and nanoparticles deposition content on different surfaces are effective on the boiling heat transfer. For investigation of depth effect, the grooves depth was increased in different geometries. By adding depth, the boiling heat transfer coefficient of water and nanofluid has increased up to 43.5% and 40.6%, respectively, because of heat transfer surface and nucleation sites density augmentation.