Generalised Isentropic Relations in Thermodynamics

Nederstigt, P.; Pecnik, Rene

doi:10.3390/en16052281

Generalised Isentropic Relations in Thermodynamics

Title

Generalised Isentropic Relations in Thermodynamics

Author

Nederstigt, P. (Student TU Delft)
Pecnik, Rene (TU Delft Energy Technology)

Date

2023

Abstract

Isentropic processes in thermodynamics are fundamental to our understanding of numerous physical phenomena across different scientific and engineering fields. They provide a theoretical reference case for the evaluation of real thermodynamic processes and observations. Yet, as analytical relations for isentropic transformations in gas dynamics are limited to ideal gases, the inability to analytically describe isentropic processes for non-ideal gases is a fundamental shortcoming. This work presents generalised isentropic relations in thermodynamics based on the work by Kouremenos et al., where three isentropic exponents γPv, γTv and γPT are introduced to replace the ideal gas isentropic exponent γ to incorporate the departure from the non-ideal gas behaviour. The general applicability of the generalised isentropic relations is presented by exploring its connections to existing isentropic models for ideal gases and incompressible liquids. Generalised formulations for the speed of sound, the Bernoulli equation, compressible isentropic flow transformations, and isentropic work are presented thereafter, connecting previously disjoint theories for gases and liquids. Lastly, the generalised expressions are demonstrated for practical engineering examples, and their accuracy is discussed.

Subject

isentropic relations
real gas thermodynamics
speed of sound
compressible fluid flows
compressibility
isentropic work

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http://resolver.tudelft.nl/uuid:1c8a23df-baf8-4bf7-8b1b-126896917e59

DOI

https://doi.org/10.3390/en16052281

ISSN

1996-1073

Source

Energies, 16 (5)

Part of collection

Institutional Repository