The piston effect induced by mass transfer in a binary fluid mixture near the critical point

TL;DR

This paper investigates how boundary mass transfer induces a piston effect in near-critical binary fluid mixtures, leading to rapid energy transfer and acoustic wave propagation, with implications for understanding critical phenomena.

Contribution

It reveals that boundary mass transfer can induce a piston effect in binary mixtures near the critical point, combining Dufour effect and acoustic wave dynamics.

Findings

Boundary mass transfer triggers piston effect in binary mixtures.

The piston effect involves rapid temperature, pressure, and density increases.

The effect can be approximated as a superposition of individual contributions.

Abstract

Similar to pure fluids, physical properties of a binary fluid mixture also exhibit singularities close to its critical point, especially when it is dilute. The numerical and theoretical results presented in this paper identify that the piston effect, a rapid energy transfer phenomenon, can be induced by boundary mass transfer in a confined near-critical binary fluid mixture. Due to the Dufour effect, both the concentration and temperature variations are responsible for the strong expansion of the boundary layer, which provokes an acoustic wave propagating in the fluid, leading to a gradual increase of the temperature, pressure and density. The detailed analysis implies that such a mixed piston effect can be approximated as a direct superposition of their respective effects in the perspective of energy transformation.