Experimental investigation of the heat transfer coefficient in pool boiling using bubble dynamic in three aqueous, electrolyte and nanofluid solutions

In this experimental research the heat transfer coefficient changes in pool boiling using bubble dynamic in three aqueous, electrolyte and nanofluid solutions have been investigated. An insulated glass tank with a cooper cylindrical element (constant roughness) was considered. The effects of the bubble dynamic parameters such as bubble departure diameter, bubble departure frequency and the density of the bubble generation points are significant and effective on the heat transfer coefficient through increasing agitagation and turbulency in the solution. Therefore increasing these parameters had a direct relation to enhance the heat transfer coefficient due to agitation conditions. Although the deposition of the nanoparticles and salt led to decrease the heat transfer coefficient, it aided to make capillary force on heat transfer surface and increase the critical heat flux point. Therefore, it could act as a positive parameter in optimum conditions. Finally, the deposition resulted in a delay in converting the nucleate boiling to film boiling. The results showed that CuO nanofluid increased the heat transfer coefficient from 6.2 (deionized water) to 8.8 kW.m -2.°C -1. This amount is about % 38.44 and % 39.76 higher than deionized water and electrolyte solution, respectively.