【摘要】 从理论分析和试验研究两个方面研究了真空状态下珠状凝结的传热特性。首先从蒸汽流场、气膜热阻和表面能3个角度进行理论分析,分析结果表明,珠状凝结的换热系数K值随着真空的提高而增大。然后进行真空条件下的珠状凝结试验,经过数据分析表明,试验结果与理论分析相吻合,即在真空条件下,凝结换热系数K值随着真空度的提高而增大,在较大Re数时(Re=34755),真空度每提高0.01MPa,换热系数可提高10%左右。更多还原

【Abstract】 In contrast to the study of bead-shaped condensing heat transfer characteristics at a normal pressure,investigated were the above characteristics in a vacuum state from the following two aspects:theoretical analysis and experimental study.First,the authors have conducted a theoretical analysis from three angles:steam flow field,air-film heat resistance and surface energy.The analytic results show that the bead-shaped condensing heat exchange coefficient K increases with an increase of vacuum.Subsequently,the authors have also performed a bead-shaped condensing test under a vacuum condition.Data analysis shows that the test results are in agreement with the theoretical analytic ones,i.e.under a vacuum condition,the condensing heat exchange coefficient K increases with an increase of vacuum.In case of a relatively big Re number(Re=34755),the heat exchange coefficient can increase by around 10% when the vacuum goes up by every 0.01 MPa.更多还原