R12和R113在四种国内常用的低肋管外冷凝放热的试验表明,目前所采用的计算α_0肋的公式,无论在定性或定量方面都与实验结果有很大出入。本文对其冷凝机理——表面张力作用作了分析,提出用两个无因次量β_σ和β_c予以表征。此外,考虑一个结构因子β_v。根据试验结果和相似理论,整理出氟里昂蒸汽在低肋管外冷凝放热的新的准则方程为■ The tests of condensation heat release of R12 and R113 outside four commonly used domestic low-fin tubes show that the formula used to calculate α_0 rib is very different from the experimental results both qualitatively and quantitatively. In this paper, the condensation mechanism of surface tension has been analyzed and two dimensionless quantities β_σ and β_c have been proposed. In addition, consider a structure factor β_v. According to the experimental results and the similar theory, the new criterion equation for condensing and releasing the heat of condensation of Freon steam outside the low-f