Abstract There is a shortage of research in the literature on the evaporation rate of the liquid pool under instantaneous conditions, which is important for the risk assessment of the liquid hazard leakage accidents. Previous perfect thermal contact model and typical pool boiling could not completely represent the boiling process in the spreading liquid pool. In this work, the spreading liquid pool was characterized as a free-surface jet impingement on the plate surface. Liquid nitrogen (LN2) was adopted to simulate liquid hydrogen (LH2) and liquid natural gas (LNG) leakage, and a series of transient jet impingement boiling experiments were conducted on the concrete surface. Liquid jetted upon the stagnation region, and the transient heat flux from the concrete surface was estimated by transfer function method. The boiling curve obtained in the present study appears significantly different from the typical pool boiling, which indicate that large deviation will occur when the typical pool boiling correlations are used for instantaneous leakage, at least for the stagnation region. A point between the onset of nucleate boiling point and fully developed nucleate boiling point was recognized, which represents the turn of forced convection dominated to nucleate boiling dominated. It is confirmed that the heat transfer was enhanced with increased jet height z, and the peak values were found at z/d = 8.

中文翻译：

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基于逆传导问题算法的混凝土表面瞬态液氮射流冲击沸腾实验研究

摘要 瞬时条件下液池蒸发率的研究缺乏文献研究，这对于液体危害泄漏事故的风险评估具有重要意义。以前完美的热接触模型和典型的池沸腾不能完全代表扩散液体池中的沸腾过程。在这项工作中，扩散液池被表征为板表面上的自由表面射流冲击。采用液氮（LN2）模拟液氢（LH2）和液化天然气（LNG）泄漏，并在混凝土表面进行了一系列瞬态射流冲击沸腾实验。液体喷射到停滞区，混凝土表面的瞬态热通量通过传递函数法估计。本研究获得的沸腾曲线与典型的池沸腾有显着差异，这表明当典型的池沸腾相关性用于瞬时泄漏时，至少在停滞区会发生很大的偏差。核沸点的起始点和完全发展的核沸点之间的点被确认，这代表强制对流占主导地位到核沸占主导地位的转变。可以证实，随着射流高度 z 的增加，传热增强，并且在 z/d = 8 处发现了峰值。核沸点的起始点和完全发展的核沸点之间的点被确认，这代表强制对流占主导地位到核沸占主导地位的转变。可以证实，随着射流高度 z 的增加，传热增强，并且在 z/d = 8 处发现了峰值。核沸点的起始点和完全发展的核沸点之间的点被确认，这代表强制对流占主导地位到核沸占主导地位的转变。可以证实，随着射流高度 z 的增加，传热增强，并且在 z/d = 8 处发现了峰值。