Ban Takahiko, Shigeta Keigo
Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Machikaneyamacho 1-3, Toyonaka City, Osaka, 560-8531, Japan.
Sci Rep. 2019 Jul 17;9(1):10368. doi: 10.1038/s41598-019-46921-2.
Flow patterns have a tendency to break the symmetry of an initial state of a system and form another spatiotemporal pattern when the system is driven far from equilibrium by temperature difference. For an annular channel, the axially symmetric flow becomes unstable beyond a given temperature difference threshold imposed in the system, leading to rotational oscillating waves. Many researchers have investigated this transition via linear stability analysis using the fundamental conservation equations and the generic model amplitude equation, i.e., the complex Ginzburg-Landau equation. Here, we present a quantitative study conducted of the thermal convection transition using thermodynamic analysis based on the maximum entropy production principle. Our analysis results reveal that the fluid system under nonequilibrium maximizes the entropy production induced by the thermodynamic flux in a direction perpendicular to the temperature difference. Further, we show that the thermodynamic flux as well as the entropy production can uniquely specify the thermodynamic states of the entire fluid system and propose an entropy production selection rule that can be used to specify the thermodynamic state of a nonequilibrium system.
当系统被温差驱动到远离平衡态时，流动模式倾向于打破系统初始状态的对称性，并形成另一种时空模式。对于环形通道，在系统中施加的给定温差阈值以上，轴对称流动会变得不稳定，从而导致旋转振荡波。许多研究人员通过使用基本守恒方程和通用模型振幅方程，即复金兹堡 - 朗道方程，进行线性稳定性分析来研究这种转变。在此，我们基于最大熵产生原理，通过热力学分析对热对流转变进行了定量研究。我们的分析结果表明，非平衡态下的流体系统在垂直于温差的方向上使由热力学通量引起的熵产生最大化。此外，我们表明热力学通量以及熵产生可以唯一地指定整个流体系统的热力学状态，并提出了一种可用于指定非平衡系统热力学状态的熵产生选择规则。
