Abstract The prediction method for the occurrence of supercritical critical heat flux (CHF) is investigated both theoretically and statistically. The supercritical CHF is defined as the lowest heat flux that causes the wall temperature (Tw) peak to occur. The new definition is helpful to avoid the confusion caused by different definitions of the heat transfer deterioration (HTD) in supercritical flow. A new theory to explain supercritical CHF mechanisms is proposed, which considers the rupture of flow stability between the liquid-like and vapor-like layers of the supercritical flow in a heated tube as the main reason for supercritical CHF phenomena. From this theory, a general mathematical model for supercritical CHF identification for upward vertical flow is derived. To substantiate the general mathematical model, two databases for supercritical CHF of water and CO2 flowing upward in vertical circular tubes are compiled from the available literature, based on which the general model is reduced to a practical correlation applicable to both supercritical water and supercritical CO2 for CHF occurring before the pseudo-critical point. The new correlation differentiates the CHF cases from the non-CHF ones very well, and it has much higher prediction accuracy than any existing counterpart.

中文翻译：

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垂直加热管中向上流动的超临界水和 CO2 的“临界热通量”预测

摘要 对超临界热通量（CHF）发生的预测方法进行了理论和统计研究。超临界 CHF 定义为导致壁温 (Tw) 峰值出现的最低热通量。新定义有助于避免因超临界流中传热劣化（HTD）定义不同而造成的混淆。提出了一种解释超临界 CHF 机理的新理论，该理论认为加热管中超临界流的类液层和类蒸汽层之间流动稳定性的破裂是超临界 CHF 现象的主要原因。根据该理论，推导出向上垂直流超临界 CHF 识别的通用数学模型。为了证实一般的数学模型，从现有文献中汇编了水和 CO2 在垂直圆管中向上流动的超临界 CHF 的两个数据库，在此基础上，通用模型被简化为适用于超临界水和超临界 CO2 在伪临界之前发生的 CHF 的实际相关性观点。新的相关性很好地将 CHF 情况与非 CHF 情况区分开来，并且比任何现有对应项具有更高的预测准确度。