City Research Online

Abstract

Organic Rankine cycles utilise organic fluids characterised by high molecular complexity, while expansion typically occurs near the critical point and the saturation vapour line. This leads to non-ideal compressible fluid dynamic effects. In such instances, the behaviour of the fluid can diverge significantly from that of an ideal gas. The experimental research on non-ideal compressible fluid dynamics, which is crucial for comprehending flow behaviour, assessing system performance, and validating both theoretical and numerical models, remains limited. In this study, a one-dimensional nozzle model, along with two-dimensional inviscid steady-state computational fluid dynamics simulations of the expansion of R245fa through a converging-diverging nozzle, are employed to analyse the flow within the test section installed in the NextORC test facility, which has recently been commissioned at City, St George’s, University of London. These numerical investigations aim to enhance the understanding of flow behaviour through the test section and help to plan the subsequent stage of experiments. In both models, real gas properties derived from lookup tables generated with NIST REFPROP utilising Helmholtz energy equations of state are incorporated. The numerical results characterise the flow through the nozzle in terms of pressure and velocity distributions under both design and off-design working conditions, which are then compared with experimental findings obtained during the initial commissioning phase.

Publication Type:	Conference or Workshop Item (Paper)
Subjects:	Q Science > QD Chemistry T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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