Large eddy simulation of a T-Junction with upstream elbow: The role of Dean vortices in thermal fatigue
Large eddy simulation of a T-Junction with upstream elbow: The role of Dean vortices in thermal fatigue
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DOI：
10.1016/j.applthermaleng.2016.07.011
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发表时间：
2016-08
影响因子：
6.4
通讯作者：
R. Tunstall;D. Laurence;R. Prosser;A. Skillen
中科院分区：
文献类型：
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作者：
R. Tunstall;D. Laurence;R. Prosser;A. Skillen
流体在t型接头中的湍流混合会在管壁产生振荡热应力，从而导致高循环热疲劳。这种热汽提问题是核电站热液压系统中的一个重要安全问题，因为它可能导致管道材料的意外失效。在这里，我们进行了一个具有上游弯道的t型结的大涡模拟（LES），并使用适当的正交分解（POD）来识别流动中的优势结构。弯曲产生一个不稳定的二次流围绕管道轴，被称为迪安旋涡旋涡开关。这为t型结下游的低频近壁温度波动提供了一种额外的机制，而不是通过在同一t型结中与直入口混合而产生的。本文强调了相邻弯头在t型接头热疲劳问题中的重要作用，以及在使用CFD作为预测工具时将其包括在内的必要性。
Turbulent mixing of fluids in a T-Junction can generate oscillating thermal stresses in pipe walls, which may lead to high cycle thermal fatigue. Thisthermal strippingproblem is an important safety issue in nuclear plant thermal-hydraulic systems, since it can lead to unexpected failure of the pipe material. Here, we carry out a large eddy simulation (LES) of a T-Junction with an upstream bend and use proper orthogonal decomposition (POD) to identify the dominant structures in the flow. The bend generates an unsteady secondary flow about the pipe axis, known asDean vortex swirl-switching. This provides an additional mechanism for low-frequency near-wall temperature fluctuations downstream of the T-Junction, over those that would be produced by mixing in the same T-Junction with straight inlets. The paper highlights the important role of neighbouring pipe bends in T-Junction thermal fatigue problems and the need to include them when using CFD as a predictive tool.