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Case Studies of Sizing Pressure Relief Valves for Two‐Phase Flow
Author(s) -
Schmidt J.,
Egan S.
Publication year - 2009
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.200800572
Subject(s) - flashing , subcooling , sizing , safety valve , thermodynamics , flow (mathematics) , mechanics , materials science , chemistry , physics , heat transfer , metallurgy , organic chemistry
The most widely accepted methods of sizing safety valves for two‐phase‐flow, namely the homogeneous equilibrium model of Leung, the HNE‐DS model proposed in ISO 4126‐10, and the latest version of the API 520 two‐point ω ‐model were compared to each other. The thermodynamic and mechanical nonequilibrium effect included in the ISO (HNE‐DS) model dominates the more rigorous property data calculation (API) at low and moderate reduced pressures, whereas the critical flow rates become closer when approaching the thermodynamic critical point. In addition, the predictive accuracy of the ISO (HNE‐DS) model was analyzed by means of roughly 3000 experimental data points from the literature. This data includes flashing steam/water, non‐flashing air/water, and initially subcooled water flowing through safety valves from several manufacturers. The calculated flow rates are in good agreement with the measurements.