Dynamic and Thermodynamic Properties of a CA Engine with Non-Instantaneous Adiabats

Ricardo Paéz-Hernández,Delfino Ladino-Luna,Juan Chimal-Eguía,Norma Sánchez-Salas

doi:10.3390/e19110632

Ricardo Paéz-Hernández, Delfino Ladino-Luna + Show 2 more

Open Access

https://doi.org/10.3390/e19110632

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Abstract

This paper presents an analysis of a Curzon and Alhborn thermal engine model where both internal irreversibilities and non-instantaneous adiabatic branches are considered, operating with maximum ecological function and maximum power output regimes. Its thermodynamic properties are shown, and an analysis of its local dynamic stability is performed. The results derived are compared throughout the work with the results obtained previously for a case in which the adiabatic branches were assumed as instantaneous. The results indicate a better performance for thermodynamic properties in the model with instantaneous adiabatic branches, whereas there is an improvement in robustness in the case where non-instantaneous adiabatic branches are considered.

Highlights

In the past 40 years, a branch of thermodynamics called finite-time thermodynamics (FTT) has been developed, based mainly on the pioneering work of Curzon and Ahlborn (CA) [1], Novikov and Chambadal [2,3] had previously reported an equivalent analysis
For the power and efficiency, respectively. These expressions are in accordance with the results reported in [27] when R = 1, and with non-instantaneous adiabatic branches (NIA) conditions at maximum power output
As has been mentioned in previous works, the optimum efficiency of the Maximum Ecological Criterion (ME) regime is greater than of the Maximum Power Output (MP) regime. In both MP and ME, the τ range is restricted by the value of R, and R decreases, reducing the performance of the thermodynamic functions engine

Summary

Introduction

In the past 40 years, a branch of thermodynamics called finite-time thermodynamics (FTT) has been developed, based mainly on the pioneering work of Curzon and Ahlborn (CA) [1], . A more realistic case, which is important to consider, is to include in the model both external and internal dissipations, since the internal dissipations influence the performance of a thermal engine Such irreversibilities are of major importance and some authors [7,8,9] have made contributions to the thermodynamic analysis of the CA engine. They proposed equivalent approaches for irreversible finite time thermodynamics, avoiding the endoreversible hypothesis defining a parameter R; all internal irreversibilities are included and when.

Thermal Properties of CA Engine with Internal Irreversibilities

Steady-State Properties and Stability Analysis of the CA Engine

Relaxation Times for NI and NIA Adiabats: A Comparative Analysis

Concluding Remarks