Abstract

The procedures developed by the authors for calculating the distribution of the liquid over the channel cross section in the dispersed-annular flows open up opportunities for more justified modeling of the conditions for the occurrence of a boiling crisis at positive values of the relative enthalpy (quality) of the flow. However, a comparison of the calculated values of the liquid flowrate in the film with the recommended values of critical heat flux (CHF) in water flow boiling in pipes has demonstrated that, in general, there is no obvious correlation between them. An analysis confirms the well-known opinion that a unified model of the flow boiling crisis in pipes cannot be constructed. At the same time, the regularities revealed in calculating the entrainment and deposition of droplets should be considered in developing a crisis model. An increase in CHF with mass flowrate, which was discovered experimentally and accounted for in the reference tables in a wide range of high pressures and mass flowrates, gives us reasons to return to Doroshchuk’s hypothesis about the “deposition crisis.” Application of the correlation for the droplet deposition rate in a disperse-annular flow enabled us to quantitatively verify this correlation. The predictions obtained using this correlation agree well with the tabulated data at a flow quality from 0.15 to 0.40 and mass flowrates above 2000 kg/(m² s). At the same time, it has been demonstrated that the widespread use of extrapolation of the CHF values recommended in the latest edition of these tables makes them, in fact, not only unreliable but also physically unjustified in a certain range of parameters. This paper identifies several such ranges wherein revision of the tables is essential.

中文翻译：

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高压管道中饱和水的流动沸腾危机

摘要

作者开发的用于计算液体在分散环形流动中通道横截面上的分布的程序，为以合理的相对焓值（质量）沸腾危机的发生条件的更合理建模提供了机会。 ）的流量。但是，将膜中液体流量的计算值与管道中水流沸腾的临界热通量（CHF）的推荐值进行比较，结果表明，通常两者之间没有明显的相关性。分析证实了众所周知的观点，即无法建立统一的管道内流动沸腾危机模型。同时，在建立危机模型时应考虑计算液滴的夹带和沉积所揭示的规律性。CHF随着质量流量的增加而增加，这种现象是通过实验发现的，并且在各种高压和质量流量范围内的参考表中得到了解释，这使我们有理由回到Doroshchuk关于“沉积危机”的假设。分散环流中液滴沉积速率相关性的应用使我们能够定量验证这种相关性。使用这种相关性获得的预测与列表数据在流量质量为0.15至0.40且质量流量高于2000 kg /（m 分散环流中液滴沉积速率相关性的应用使我们能够定量验证这种相关性。使用这种相关性获得的预测与列表数据在流量质量为0.15至0.40且质量流量高于2000 kg /（m 分散环流中液滴沉积速率相关性的应用使我们能够定量验证这种相关性。使用这种相关性获得的预测与列表数据在流量质量为0.15至0.40且质量流量高于2000 kg /（m² s）。同时，已经证明，最新版这些表中推荐的CHF值的外推法的广泛使用实际上使它们在某些参数范围内不仅不可靠，而且在物理上也不合理。本文确定了几个这样的范围，其中表的修订是必不可少的。