Entropy generation and exergy destruction in transient and compressible steam flow through ISA 1932 measuring nozzle

Krzysztof J. Wołosz

Energy, 2025, vol. 330, issue C

Abstract: In the measurement systems where mass flow rate is measured by means of pressure drop the detailed energy losses have not been analysed. This study focused on entropy generation and exergy destruction of superheated steam flow through an ISA 1932 measuring nozzle at inlet mass flow rate ṁ=17.6kg/s. The entropy and exergy analysis were applied for compressible and transient flow to provide exergy destruction data based. The flow behaviour was calculated by using two unsteady Reynolds averaged Navier–Stokes model: k-ωSST 2006 and realizable k-ɛ. The results were compared to the values presented in applicable industry standard. The reference values of exergy analysis was assumed to be one in undisturbed flow in the pipeline. Although the results of energy flow rates were similar for both applied turbulence models yet the entropy and exergy rate differs widely up to 55%. The research shows that the entropy generated part for heat transfer in negligible small in relation to total entropy. The maximum value of the total entropy generation rate is 45.33 W/(m3 K), corresponding exergy destruction rate is 4 190 W almost entirely caused by viscous dissipation. This corresponds to the values of the dimensionless total entropy generation 8.68×10−5 for the Reynolds number Re =3×106.

Keywords: Energy efficiency; Exergy analysis; Water steam flow; Computational fluid dynamics; Energy losses; Transient flow; Exergy destruction; Measurement systems (search for similar items in EconPapers)
Date: 2025
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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:330:y:2025:i:c:s0360544225022194

DOI: 10.1016/j.energy.2025.136577

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