| 摘要: |
| 本文在自然对流情况下，基于双膜理论和边界层理论，考虑气液界面热阻，建立了滴形管外气液膜厚度及传热系数的数学模型，得到不同初始参数下气、液膜厚度，气、液膜热阻，气液界面热阻、凝液量和传热系数沿管壁的分布规律。结果表明：其他条件不变，随着混合气压力的增大(由81325Pa增加至121325Pa时)，液膜厚度增大(约7%)，传热系数减小(约30%)。随着不凝气体质量含量的增加(由0.1%增加至10%时)，虽然气膜厚度减小(约52%)，但气膜内不凝气体的质量含量增加(约58%)，气膜传热阻力增大(约61%)。对于当量直径相同的滴形管，其他条件不变，滴形管下半部分曲率越大，越易发生液膜分离，传热系数越大。 |
| 关键词: 滴形管 不凝气体 凝结 换热特性 |
| DOI： |
| 投稿时间：2018-01-17 修订日期：2018-03-14
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| 基金项目: |
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| Study on Condensation Heat Transfer Performance of Natural Convection outside a Drop Tube Containing |
| Li Huijun,Jia Yiqiong |
| (School of Energy Power and Mechanical Engineering, North China Electric Power University) |
| Abstract: |
| Based on the double-film and boundary-layer theories, a mathematical model of the gas- and liquid-film thicknesses and the heat transfer coefficient of a drop tube were established, which considers the vapor-liquid interfacial thermal resistance. The distributions of the gas- and liquid-film thicknesses and heat transfer coefficient along the tube wall under different initial parameters and curvatures were obtained by simulation. The results indicate that the heat transfer coefficient is decreased (by approximately 30%) and the liquid-film thickness is increased (by approximately 7%) with the increase in the mixing gas pressure (when the pressure is from 81 325 to 121 325 Pa). With the increase in the non-condensable gas mass content (when the non-condensable gas-mass content is from 0.1% to 10%), the film thickness is decreased (by approximately 52%), the mass content of the non-condensable gas in the gas film is increased (by approximately 58%), and the heat transfer resistance of the gas film is increased (by approximately 61%). For an equivalent drop-tube diameter with the other conditions remaining unchanged, the larger the curvature is, the easier the separation of the liquid film is, and the larger the heat transfer coefficient is. |
| Key words: drop tube non condensable gas condensation heat transfer characteristics |
