空気-水系噴霧流リビュレット状液膜領域の伝熱特性

概要

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Characteristics of heat transfer in the rivulet-like liquid film region of an air-water dispersed flow in a heated vertical pipe have been studied. Simultaneous multi-point measurements show that wall-temperature fluctuations in this region are quite large and of low frequency, being compared with those reported previously for single-component two-phase flows, and that such fluctuations are caused by the meandering motion of rivulets. A model for predicting heat transfer mechanism is constructed by introducing the critical liquid-film thickness and the wetting fraction, with which the breakdown of annular liquid film and the subsequent appearance of wet and dry surfaces in the rivulet-like liquid film are handled. It is demonstrated that the numerical analysis based on the present model can predict well the wall-temperature characteristics observed experimentally. It is also shown that there is a clear correlation between the critical liquid-film thickness determined in the analysis and the friction velocity estimated at a liquid-gas interface in the annular liquid film region.
社団法人日本機械学会の論文
1998-07-25