Heat Transfer Characteristics Based on Micro-Layer Configuration in Nucleate Boiling

The objective of the study is to elucidate the contribution of micro-layer on heat transfer in nucleate pool boiling of isolated bubble region on the basis of the measurement of configuration of micro-layer. The distribution of micro-layer thickness formed under a growing bubble was measured by laser extinction method using specially devised system with a thin optical fiber in thin tube and gas blowing in the previous report. In this report, the dominant factors determining the characteristics of micro-layer such as micro-layer thickness distribution, duration of micro-layer existence, size of micro-layer area on the heat transfer surface and so-forth were expressed by nondimensional form based on the similarity of bubble growth rate. Finally, the contribution of evaporation from micro-layer in nucleate boiling of isolated bubble region was shown by using the relations among dominant factors.