Abstract The scope of this work comprises the study of the mathematical nature of the RELAP5 two-fluid model (TFM) for two-component (water and non-condensable gas (helium)) and two phases (liquid and vapor) mixture flows, and to predict the accuracy of the model under these flow conditions. The method of characteristics is applied to check the non-hyperbolic nature of conservation equations of RELAP5 for some sample fluid conditions. The sample problem selected here is a small break in helium-water heat exchanger primary tubes (containing high pressure and high-temperature helium gas) into the secondary shell (water) side high-temperature gas-cooled reactor, that causes mixing of helium-steam and liquid water and results in two-component two-phase flow. This sample problem is selected to address the RELAP5 model behavior and its sensitive nature under multi-component two-phase analysis. Linear stability analysis is also performed to check the error growth rates for the sample fluid conditions.

中文翻译：

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RELAP5二流体模型的二组分两相流特性及线性稳定性分析

摘要 这项工作的范围包括研究 RELAP5 双流体模型 (TFM) 的数学性质，用于双组分（水和不可凝气体（氦））和两相（液体和蒸汽）混合物流，以及在这些流动条件下预测模型的准确性。应用特征法检验了某些样品流体条件下RELAP5守恒方程的非双曲性质。这里选择的示例问题是氦水换热器初级管（含有高压和高温氦气）进入二级壳（水）侧高温气冷反应堆的小断裂，导致氦-蒸汽和液态水并导致双组分两相流。选择此示例问题是为了解决 RELAP5 模型行为及其在多组分两相分析下的敏感性。还执行线性稳定性分析以检查样本流体条件的误差增长率。