Nucleate Pool Boiling From Coated and Spirally Wrapped Tubes in Saturated R-134a and R-600a at Low Moderate Heat Flux

摘要

Pool nucleate boiling heat transfer experiments from coated surfaces with porous cooper (Cu) and molybdenum (Mo) and spirally wrapped with helical wire on copper surfaces with micro-roughness immersed in saturated R134a and R-600a were conducted. The influence of coating thickness, porosity, wrapped helical angle, and wire pitch on heat transfer and boiling characteristics including bubble parameters were studied. The en- hanced surface heat transfer coefficients with R-600a as refrigerant found are 2.4 times higher than those of the smooth surfaces.