Numerical simulation of subcooled and superheated jets under thermodynamic non-equilibrium

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  FlashFOAM had been developed within the frame of OpenFOAM for simulating flashing jets  It accounts for the inter-phase heat transfer with the Homogeneous Relaxation Model (HRM).  A series of validation studies dedicated to long nozzles are reported.  The code has demonstrated its capability to capture the flow characteristics and vapour generation in cryogenic liquid jets.  The dependency of the geometry of the nozzles, pressure and subcooled degree on the vapour generation has been analysed.  The validation study has demonstrated that FlashFOAM can be used to simulate flash boiling scenarios accurately and predict the properties of flash atomisation.

Injector and Combustion Chamber Design for a Nitrous Oxide and Ethanol Rocket Engine

“…The main contribution of this publication to the current project is the general understatement of what flash-boiling is and how it can be modeled analytically or semi-empirically. (Lyras et al, 2018), on the other hand, focuses on modeling flash-boiling phenomena in injectors by means of numerical methods. It describes the implementation of a new…”

Numerical simulation of flashing jets atomisation using a unified approach

“…This equation is used for the pressure update (without the pressure gradient correction) and includes the effects of the surface tension, thermal non-equilibrium and multiphase mixing (Lyras et al 2018). In this paper an additional term for thermal expansion is incorporated.…”

“…The liquid volume fraction φ l is calculated from the mass fraction of the liquid according to Lyras et al (2018). The surface tension is denoted with σ and the curvature of the interface with κ and is given by…”

“…An algorithm that links the standard pressure-velocity coupling algorithm to the HRM and volume of fluid method is used as a basis to simulate cryogenic and water jets (Lyras et al, 2018). The method has been previously derived for examining the internal flow regimes of superheated liquids and is coupled here with a spray model for modelling atomisation.…”

Numerical investigation of the effect of the shape of the nozzle on the flash boiling phenomenon

“…Moreover, sensitivity analysis was carried out concerning the grid independency, turbulence modelling approaches, near-wall treatment approaches, turbulence inlet parameters and semi-empirical coefficients. Recently, Lyras et al [14] presented the compressible RANS solver FlashFOAM for calculating the phase change within various nozzle geometries undergoing rapid pressure drops. The solver was developed in the open source code OpenFOAM.…”