Friction Factor Correlation for Regenerator Working in a Travelling-Wave Thermoacoustic System
Friction Factor Correlation for Regenerator Working in a Travelling-Wave Thermoacoustic System
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DOI：
10.3390/app7030253
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发表时间：
2017-03
期刊：
影响因子：
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通讯作者：
F. A. M. Saat;A. Jaworski
中科院分区：
文献类型：
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作者：
F. A. M. Saat;A. Jaworski
回热器是一种多孔固体结构，在行波热声系统中起着重要的作用。它为工作气体提供了必要的接触表面和热容量，以在声振荡流条件下进行热力学循环。然而，它也会产生压降，从而降低整个系统的性能。理想情况下，在行波系统中，回热器中振荡压力和速度之间的相位角应该为零，或尽可能接近零。在这项研究中，再生器的流体动力学条件进行了研究实验（在一个专门建造的钻机提供行波定相）和数值。一个二维的ANSYS FLUENT计算流体动力学模型，捕捉实验条件的重要特征，已经开发。研究结果表明，一个稳态的相关性，通常用于设计热声系统，是适用的行波相位角保持。然而，对于粗网格再生器，结果显示有趣的“相移”现象，这可能会限制相关性的有效性。目前的实验和计算流体力学研究是重要的预测粘性损失的未来模型的热声系统。
Regenerator is a porous solid structure which is important in the travelling-wave thermoacoustic system. It provides the necessary contact surface and thermal capacity for the working gas to undergo a thermodynamic cycle under acoustic oscillatory flow conditions. However, it also creates a pressure drop that could degrade the overall system performance. Ideally, in a travelling-wave system, the phase angle between oscillating pressure and velocity in the regenerator should be zero, or as close to zero as possible. In this study, the hydrodynamic condition of a regenerator has been investigated both experimentally (in a purpose-built rig providing a travelling-wave phasing) and numerically. A two-dimensional ANSYS FLUENT CFD model, capturing the important features of the experimental conditions, has been developed. The findings suggest that a steady-state correlation, commonly used in designing thermoacoustic systems, is applicable provided that the travelling-wave phase angle is maintained. However, for coarse mesh regenerators, the results show interesting “phase shifting” phenomena, which may limit the correlation validity. Current experimental and CFD studies are important for predicting the viscous losses in future models of thermoacoustic systems.