Abstract The purpose of this work is to present an analytical model to predict the Geyser Boiling limit for high temperature two-phase thermosyphons. By this limit, it is understood the minimum heat flux required to the thermosyphon to work in the ideal operation regime. The Geyser Boiling phenomenon is characterized by a nucleate pool boiling instability that occurs in the evaporator mainly at low heat fluxes, resulting in abrupt synchronized temperature and pressure oscillations, in both the evaporator and condenser, not recommended in most actual applications. A new dimensionless “bubble release number”, which represents the wall superheat necessary to generate a bubble at given diameter and temperature operation conditions, is proposed. It is observed experimentally that thermosyphons operate in ideal regime, surpassing the Geyser Boiling, when the bubble release number is less than 0.01, value taken as the Geyser Boiling limit. Therefore, the minimum heat transfer rate necessary to operate high temperature thermosyphons in de ideal regime is given by the Geyser Boiling limit. The modeling presented in this paper can be used as an engineering tool to design high performance, safe operation systems, involving high temperature two-phase thermosyphons that operate outside the Geyser Boiling regime.

中文翻译：

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高温两相热虹吸间歇泉沸腾极限的预测

摘要 这项工作的目的是提出一个分析模型来预测高温两相热虹吸的间歇泉沸腾极限。通过该限制，可以理解热虹吸管在理想操作状态下工作所需的最小热通量。间歇泉沸腾现象的特点是在蒸发器中主要发生在低热通量下的核池沸腾不稳定性，导致蒸发器和冷凝器中的突然同步温度和压力振荡，在大多数实际应用中不推荐使用。提出了一个新的无量纲“气泡释放数”，它表示在给定直径和温度操作条件下产生气泡所需的壁面过热度。实验观察到，热虹吸管在理想状态下运行，超过了间歇泉沸腾，当气泡释放数小于 0.01 时，取该值作为间歇泉沸腾极限。因此，在理想状态下操作高温热虹吸管所需的最小传热率由间歇泉沸腾极限给出。本文中提出的建模可用作设计高性能、安全操作系统的工程工具，涉及在间歇泉沸腾状态之外运行的高温两相热虹吸管。