有限長さの垂直円柱まわりの膜沸騰熱伝達の解析 : 沸騰曲線の予測

概要

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The film boiling heat transfer from a vertically placed cylinder of finite-length was analyzed to predict the overall heat transfer rate around the cylinder in terms of boiling curve. The overall heat transfer rate around the cylinder was determined by taking into account every convective heat transfer on the bottom, side and top surfaces of the cylinder. The.local heat transfer rate on the bottom surface was analyzed by the method similar to that recently developed by the authors for a downward-facing horizontal circular plate. Bromley's model for the vertical surface was modified to accommodate the continuity of the vapor flow rate at the lower end of the side wall, where the vapor film had a finite thickness due to the vapor inflow out of the bottom surface. Berenson's model was adopted on the top surface, independent of the vapor flowing upward along the side wall. The effects of length and diameter of the cylinder on the overall heat transfer rate were discussed in terms of boiling curve and the present prediction method was compared with the experimental data obtained by the authors.