Direction of spontaneous processes in non-equilibrium systems with movable/permeable internal walls
arxiv(2024)
摘要
The second law of equilibrium thermodynamics explains the direction of
spontaneous processes in a system after removing internal constraints. When the
system only exchanges energy with the environment as heat, the second law
states that spontaneous processes at constant temperature satisfy: d
U - δ Q ≤ 0. Here, d U is the infinitesimal change of the
internal energy, and δ Q is the infinitesimal heat exchanged in the
process. We will consider ideal gas, van der Waals gas, and a binary mixture of
ideal gases in a heat flow. We will divide each system into two subsystems by a
movable wall. We will show that the direction of the motion of the wall, after
release, at constant boundary conditions is determined by the same inequality
as in equilibrium thermodynamics. The only difference between equilibrium and
non-equilibrium is the dependence of the net heat change, δ Q, on the
state parameters of the system. We will study the influence of the
gravitational field. The inequality determining the direction of motion of the
internal wall at constant boundary conditions is d E - δ Q -
δ W_p ≤ 0, where d E is the change of the total energy
(internal and gravitational), and δ W_p is the infinitesimal work
performed by gravity. We will also consider a wall thick and permeable to gas
particles and derive Archimedes' principle in the heat flow. Finally, we will
study the ideal gas's Couette flow, where the direction of the motion of the
internal wall follows from the inequality d E - δ Q - δ W_s
≤ 0, with d E being the infinitesimal change of the total energy
(internal and kinetic) and δ W_s the infinitesimal work exchanged with
the environment due to shear force. Ultimately, we will synthesize all these
cases in a framework of the second law of non-equilibrium thermodynamics.
更多查看译文
AI 理解论文
溯源树
样例
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要