外场作用下热力学平衡判据及其应用

发布时间：2018-01-12 20:43

本文关键词：外场作用下热力学平衡判据及其应用　出处：《华南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：热力学中的平衡态是指系统的各个宏观量都不变时,它能够永久地停留在该状态。当均匀系统与外界达到平衡时,系统的热力学参量必须满足一定的条件,称为系统的平衡条件。热力学平衡判据是利用热力学函数来判断系统是否达到了平衡。自从人们发现外场对平衡有着显著的影响效果,并且,在化工、医药等生产中有着重要的作用,越来越多的科学工作者开始着手研究外场对平衡的影响。有些从实验方面来研究外场对系统平衡的影响;有些则通过分子模拟得出外场对平衡的影响。他们的工作能从一些方面说明一些问题,但是却没有得到一个普遍性的结论。由于热力学具有普遍性,所以本文将用热力学方法来研究外场作用下的系统平衡问题。首先,从能量公理出发,根据热力学第一和第二定律推导出了外场作用下热力学平衡判据普遍化形式。热力学中熵判据、自由能判据和吉布斯函数判据在存在外场时虽然形式没有变,但是由于受到外场的限制,它们的使用条件发生了变化。用外场作用下的热力学平衡判据分析对磁制冷过程和电化学过程,得到了合理的结论。通过外场作用下热力学平衡判据,推导出了重力场和电场作用下的相平衡条件。根据重力场中的相平衡条件得出了气体压强和其高度的关系式,结果与经典书籍中的结论一致;根据电场作用下的相平衡条件在等温等压和等温等容情况下的不同形式,推导出了液体饱和蒸汽压和电场强度的关系式,通过计算发现,这两个公式是等价的,电场作用可以使液体饱和蒸汽压略有下降,这和文献值相符。
[Abstract]:The equilibrium state in thermodynamics means that when the macroscopical quantities of the system are not changed, it can stay in this state permanently. When the equilibrium between the homogeneous system and the outside world is reached, the thermodynamic parameters of the system must meet certain conditions. It is called the equilibrium condition of the system. The thermodynamic equilibrium criterion is to use thermodynamic function to judge whether the system has reached equilibrium. Since it was found that the external field has a remarkable effect on the equilibrium, and, in the chemical industry. More and more scientists begin to study the effects of the field on the balance. Some of them study the effects of the field on the balance of the system from the aspect of experiments, and more and more scientists begin to study the effects of the field on the balance of the system. Some get the effect of the external field on the equilibrium by molecular simulation. Their work can explain some problems from some aspects, but not a universal conclusion, because thermodynamics is universal. Therefore, the thermodynamic method will be used to study the system equilibrium problem under the external field. Firstly, starting from the energy axiom. According to the first and second laws of thermodynamics, the generalized form of thermodynamic equilibrium criterion under the action of external field is derived. The entropy criterion, free energy criterion and Gibbs function criterion in thermodynamics do not change when the external field exists. However, due to the limitation of the external field, their application conditions have changed. The magnetic refrigeration process and the electrochemical process are analyzed by the thermodynamic equilibrium criterion under the external field. A reasonable conclusion is obtained. The thermodynamic equilibrium criterion is obtained under the action of external field. The phase equilibrium conditions under the action of gravity field and electric field are derived. According to the phase equilibrium condition in gravity field, the relationship between gas pressure and its height is obtained, and the results are consistent with those in classical books. According to the different forms of phase equilibrium conditions under the action of electric field under isothermal isobaric and isothermal isobaric conditions, the relationship between saturated vapor pressure of liquid and electric field strength is derived, and the two formulas are found to be equivalent by calculation. The saturated vapor pressure of the liquid can be slightly reduced by the electric field, which is in accordance with the literature.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O642.4

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