Simple realization of the polytropic process with a finite-sized reservoir

TL;DR

This paper presents a simple model for realizing polytropic processes using a finite-sized thermal reservoir, enhancing thermodynamics teaching and understanding of process origins.

Contribution

It introduces a model connecting polytropic processes to finite reservoirs, providing educational insights and experimental implementation details.

Findings

Deepens understanding of thermodynamic processes in education.

Explores phenomena due to finite reservoir size.

Discusses experimental realization with realistic parameters.

Abstract

In many textbooks of thermodynamics, the polytropic process is usually introduced by defining its process equation rather than analyzing its actual origin. We realize a polytropic process of an ideal gas system when it is thermally contact with a reservoir whose heat capacity is a constant. This model can deepen students' understanding of typical thermodynamic processes, such as isothermal and adiabatic processes, in the teaching of thermodynamics. Moreover, it can inspire students to explore some interesting phenomena caused by the finiteness of the reservoir. The experimental implementation of the proposed model with realistic parameters is also discussed.