雷诺数关系式对膜状凝结湍流区传热计算的影响

膜状凝结现象广泛存在于核电站安全壳和稳压器中。关于膜状凝结液膜湍流区的传热模型,目前未明确辨析基于质量和能量关系的两种雷诺数关系式的差别。本文针对管外纯蒸汽自然对流膜状冷凝传热,定量地分析雷诺数关系式对膜状凝结液膜湍流区传热计算的影响。基于液膜湍流区修正项的一般性假设,推导了膜状凝结湍流区传热系数的表达式。同时,分别与雷诺数关系式Remass和Reenergy联立,求解得到不同雷诺数关系式之间以及对应的膜状凝结传热系数之间的关系。分析表明:受普朗特数Pr的影响,在膜状凝结液膜湍流区,雷诺数关系式Remass和Reenergy差别明显,并存在关于Pr的分界点。基于Remass和Reenergy得到的膜状凝结平均传热系数及其相对偏差是Re和Pr的非线性函数。当0.1Pr4.0且Re1 600时,基于Reenergy和Remass得到的膜状凝结平均传热系数相对偏差在-60%和+60%之间。通过实验和理论验证,在膜状凝结液膜湍流区基于Reenergy得到的膜状凝结传热系数更加准确。

Effect of Reynolds Correlations on Heat Transfer Calculation of Film Condensation in Turbulent Flow

Film condensation widely exists in the compact containment and the pressurizer of nuclear power plant.At present,the difference of Reynolds correlations of the mass relation and the energy relation is not distinguished in the turbulent flow of film condensation.For outer tube natural-convection film condensation of pure steam,the effect of Reynolds correlations on the characteristic of film condensation in the turbulent flow was quantitatively studied.Based on the general assumption of the modified term in turbulent flow of film condensation,the general form of heat transfer coefficient was deduced.In addition,by solving a set of simultaneous equations of the heat transfer coefficients and Reynolds correlations of Remass and Reenergy,the general relations of Reynolds correlation and the corresponding heat transfer coefficients were obtained respectively.It is indicated that in turbulent flow region,Remass and Reenergy are quite different.Their relation is greatly influenced by the Prandtl number,and the demarcation point of Prandtl number is presented.The corresponding average heat transfer coefficients and their relative deviations are the non-linear function of Reynolds number (Re) and Prandtl number (Pr).When 0.11 600,the value of the relative deviation for the average heat transfer coefficients is generally within-60% to +60%.By validating experimentally and theoretically,Reenergy leads to more accurate calculations in turbulent flow region.