DOI: 10.1615/ICHMT.2015.THMT-15
ISBN Print: 978-1-56700-427-4
ISBN CD: 978-1-56700-428-8
Experimental study of surface configuration effect on saturated pool boiling
RÉSUMÉ
Boiling is a process in which heat and mass transfer occur simultaneously. When a heated surface immersed in liquid, vapor bubbles form, grow, detach from the surface and move upward. This movement leads to form a turbulent flow in the bulk liquid. In this study, experiments are conducted for saturated pool boiling of water at local atmospheric pressure (863 mbar) over horizontal stainless steel cylinders with various surface configurations. Average surface roughness of the cylinders is changed from 0.034 µm to 2.549 µm and imposed heat flux varies from 0.310 kW/m2 to 125.62 kW/m2. Effect of depth and number of cavities on heat transfer is also studied. Results show that turbulence intensity changes with changing surface roughness and for surface roughness up to 0.794 µm, the increase in the surface roughness enhances heat transfer in the nucleate pool boiling region and for the surface roughness above this value, boiling heat transfer coefficient is reduced. The experimental results also revealed that heat transfer coefficient is not only depending on the average surface roughness but also on the depth and number of cavities on the surface subjected to boiling.