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首页> 外文期刊>Journal of Hydraulic Engineering >Unitary Framework for Hydraulic Mathematical Models of Transient Cavitation in Pipes: Numerical Analysis of 1D and 2D Flow
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Unitary Framework for Hydraulic Mathematical Models of Transient Cavitation in Pipes: Numerical Analysis of 1D and 2D Flow

机译：管道瞬态空化水力数学模型的统一框架：一维和二维流动的数值分析

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This paper deals with two-phase flow models of transient cavitating pipe flow, showing how bubble-flow models and shallow-water models can be considered in a unitary framework by only changing the geometry of the cross section. A bubble-flow cavitation model and a shallow-water cavitation model are proposed, taking into account the convective terms. Computational results are compared with those of two previous simpler bubble-flow models and with experimental measurements reported in the literature. Both quasi-steady one-dimensional (1D) and quasi-two-dimensional (2D) forms of all models are considered. For the examined cases, numerical analysis shows that 1D models converge for similar grid resolution; 2D models reach convergence with coarser longitudinal grids than, or at most with same grids as, 1D models. Comparison with measurements reveals that in order to properly investigate the capabilities of models, the computation must proceed way in time. Indeed, the first cavitation event (or, in some cases, the first few cavitation events) is very well reproduced with all models, both 1D and 2D, but over time remarkable differences in numerical results can be observed. The 1D models overestimate head values, generally do not reproduce well the shape of the function, and are delayed in time with respect to measurements, whereas 2D models reproduce very well the peaks and shapes of the head as function of time, but their results are anticipated in time with respect to measurements, suggesting that energy dissipation is overestimated. The comparison of results of the different 2D models shows, for the examined cases, very small differences, justifying the adoption of simpler models. (C) 2017 American Society of Civil Engineers.
机译：本文涉及瞬态空化管流的两相流模型，显示了如何仅通过改变横截面的几何形状就可以在统一框架中考虑气泡流模型和浅水模型。考虑到对流项，提出了气泡流空化模型和浅水空化模型。计算结果与之前的两个较简单的气泡流动模型的结果以及文献中报道的实验测量结果进行了比较。所有模型的准稳态一维（1D）和准二维（2D）形式均被考虑。对于所检查的情况，数值分析表明，对于相似的网格分辨率，一维模型收敛。 2D模型的纵向网格比1D模型更粗糙，或者最多具有与1D模型相同的网格。与测量值的比较表明，为了正确调查模型的功能，计算必须及时进行。确实，所有一维和二维模型都很好地再现了第一个空化事件（或在某些情况下，前几个空化事件），但是随着时间的流逝，数值结果会出现显着差异。一维模型高估了头值，通常无法很好地再现功能的形状，并且在测量方面的时间延迟，而一维模型可以很好地再现随时间变化的头的峰值和形状，但是它们的结果是关于测量的时间预期，表明能量消耗被高估了。比较不同2D模型结果的结果表明，对于所检查的案例，差异很小，证明采用更简单的模型是合理的。 （C）2017年美国土木工程师学会。

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