Real gas effects in supersonic nozzles

Lead Research Organisation: Imperial College London
Department Name: Dept of Mechanical Engineering

Abstract

The project aims to numerically investigate the role played by the equation of state (EoS) on gas dynamics in a convergent-divergent nozzle. Considering an EoS representative of the behaviour of dense gases close to the thermodynamic critical point (a configuration occurring in ORC turbines for example), a variety of non-classical flow configurations (e.g. expansion shocks) can be observed. This project aims to explore some of these configurations and investigate their response to perturbations. Simulations will be carried out using the in-house compressible flow code CompReal.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509486/1 01/10/2016 30/09/2021
2168793 Studentship EP/N509486/1 13/11/2017 12/05/2021 Stephen Nutt Winn
 
Description This project involves numerically investigating the effect of the equation of state on gas dynamics when pressure is no longer a linear function of density (i.e. when the ideal gas law p=rhoRT no longer holds). In the work carried out so far, the van der Waals gas model is used to illustrate non-ideal effects. Despite its quantitative inaccuracy, it allows non-ideal effects to be illustrated qualitatively.
Initial two-dimensional simulations were carried out to investigate shock-transfer properties in non-uniform flow. The study involved sending an upstream perturbation through a curved shock to observe the resulting downstream perturbation. The curved shock was generated by a supersonic flow meeting a blunt object. The perturbation considered is that of an entropy mode (representative of local heating .e.g by laser). The flexibility associated with a non-ideal gas i.e. the ability to control the redistribution of energy onto the different modes which comes from the additional dependency of the transmitted and generated modes on the local curvature of the Hugoniot line rather than simply the upstream conditions is illustrated by looking at the effect of the perturbation on surface pressure and the force generated over time.
Exploitation Route The effects studied could be exploited for flow control purposes (e.g. during atmospheric entry) or help to understand effects in Organic Rankine Cycle turbines (e.g. as hot and cold spots are advected through shocks between the turbine blades).
Sectors Aerospace, Defence and Marine

URL http://rpsonline.com.sg/rps2prod/ISSW32/e-proceedings/html/0373.xml