ON THE INFLUENCE OF THE THICKNESS AND THERMAL PROPERTIES OF HEATING WALLS ON THE HEAT TRANSFER COEFFICIENT IN NUCLEATE BOILING

摘要

An experimental investigation was conducted on saturated pool boiling of water at atmospheric pressure using thin walled electrically heated cylinders made of various metals, and suspended horizontally. These cylinders were made by plating copper, silver, zinc, nickel and tin on non-metallic rods. The wall thickness ranged from 5.0 to 250 micrometers. The experiments have shown that the heat transfer coefficient is strongly dependent upon the wall thickness of the cylinder. Results indicated that if the thermal conductivity of the metal is small, the higher the influence of the wall thickness is. However, no appreciable effect was observed for metals having a higher conductivity, such as copper or silver.