Peters Michael H
Department of Chemical and Life Science Engineering, Virginia Commonwealth University, 601 West Main St., Richmond, VA 23284, USA.
Entropy (Basel). 2019 Mar 27;21(4):330. doi: 10.3390/e21040330.
In this study, we generalize our previous methods for obtaining entropy generation in gases without the need to carry through a specific expansion method, such as the Chapman-Enskog method. The generalization, which is based on a scaling analysis, allows for the study of entropy generation in gases for any arbitrary state of the gas and consistently across the conservation equations of mass, momentum, energy, and entropy. Thus, it is shown that it is theoretically possible to alter specific expressions and associated physical outcomes for entropy generation by changing the operating process gas state to regions significantly different than the perturbed, local equilibrium or Chapman-Enskog type state. Such flows could include, for example, hypersonic flows or flows that may be generally called hyper-equilibrium state flows. Our formal scaling analysis also provides partial insight into the nature of entropy generation from an informatics perspective, where we specifically demonstrate the association of entropy generation in gases with uncertainty generated by the approximation error associated with density function expansions.
在本研究中，我们推广了我们之前用于在无需采用特定膨胀方法（如查普曼 - 恩斯科格方法）的情况下获取气体中熵产生的方法。这种基于尺度分析的推广，使得能够研究气体在任意状态下的熵产生情况，并且能在质量、动量、能量和熵的守恒方程之间保持一致性。因此，结果表明，通过将运行过程中的气体状态改变到与受扰的局部平衡态或查普曼 - 恩斯科格型状态显著不同的区域，从理论上有可能改变熵产生的特定表达式及相关的物理结果。此类流动例如可能包括高超音速流动或通常可称为超平衡态流动的流动。我们的形式尺度分析还从信息学角度对熵产生的本质提供了部分见解，在此我们具体展示了气体中熵产生与由密度函数展开相关的近似误差所产生的不确定性之间的关联。
