Abstract
The purpose of this article is to perform a comparative study of a reversible heat engine with an ideal or real gas as a working fluid and to determine the change in its efficiency depending on the thermodynamic characteristics of the working fluid. The main research method is the method of thermodynamic potentials, based primarily on the analysis of changes in the free and internal energy of an ideal and real gas in a cyclic process. The theory of thermodynamic potentials is used to consider the Carnot quasistatic heat engine. A comparative analysis of its operation is carried out, for a cycle with both an ideal and a real gas as a working fluid. The possibility of analyzing cyclic processes occurring in heat engines using the method of thermodynamic potentials has been identified and substantiated. The study has shown that the existing formulation of the Carnot’s theorem is valid only for ideal gas as a working fluid. Based on the work carried out, the Carnot’s theorem in the general case can be formulated, for example, as follows: the efficiency of the heat engine ηr, when it operates at the reversible Carnot cycle with real gas as a working fluid, is determined by the following expression:hr= 1 - TB /TA + ε,where TA and TB are the temperatures of the upper and lower isotherms of the Carnot cycle, respectively; ε is the correction term (positive or negative), depending on the thermodynamic properties of a real gas, which tends to zero as the properties of a real gas approach the properties of an ideal gas.
Highlights
In a number of previous publications [1, 2, 3], the author used the method of thermodynamic potentials [4, 5] to analyze the simplest thermodynamic processes
This work explores the behavior of real gas in thermodynamic cycles and the influence of its properties on the efficiency of heat engines basing on the basic principles underlying the earlier publications
In order to simplify further calculations, we assume that the device under consideration, operating with either ideal or real gas, is in vacuum, and to analyze its operation we use the theory of thermodynamic potentials, assuming that only one mole of gas is always used in the system
Summary
In a number of previous publications [1, 2, 3], the author used the method of thermodynamic potentials [4, 5] to analyze the simplest thermodynamic processes (mixing of ideal gases and isothermic equilibrium and non-equilibrium expansion of an ideal gas). This work explores the behavior of real gas in thermodynamic cycles and the influence of its properties on the efficiency of heat engines basing on the basic principles underlying the earlier publications. 81], “Carnot showed that a reversible cyclic heat engine must perform the maximum work (driving force) ...”. Since the direct process gives more work than it is required to complete the reverse process, the result is a gain in work. Carnot argued that this was impossible." Note that in this discussion there is a substitution of concepts. “Joule and Thomson showed that the vast majority
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Power engineering: research, equipment, technology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
