Difference between revisions of "Contrib/CompressibleMixingPhaseChangeFoam"
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* '''Case #2 - hot water flashing in the nozzle''' | * '''Case #2 - hot water flashing in the nozzle''' | ||
+ | Problem description, initial and boundary conditions are shown on the figure | ||
+ | [[File:water-flashing.jpg]] |
Revision as of 16:13, 6 August 2013
Solver for two fluids with phase change (for example - water <---> steam), pressure and temperature density dependence Valid versions:
1 Model Equations Derivation
VALID OPENFOAM VERSION - 2.1.0
- Equation of state
Low-compressible fluid:
Ideal gas:
By combining this equations, we can get general relation:
where computed with respect to previous formulations
mixture density calculated as
Here, and afterthere indices:
1,l,f - for liquid (heavy media with low compressibility)
2,g,s - for gas (light media (like steam) with big compressibility)
without index - mixture variable (or all variables local to some phase)
- Liquid volume transport
Let us consider transport of liquid (heavy phase) volume fraction :
By converting to volume fluxes we get:
Using equation of state, we can reformulate substantial derivative for density in terms of pressure for any phase:
- General rule for converting from mass to volume fluxes in transport equation
- Momentum equation (velocity prediction)
by substituting piezometric pressure we get:
- Pressure equation obtained by summation of equation for volume phase fraction of liquid and gas phases:
- Energy equation
Energy equation for mixture temperature obtained from sum of energy equations for each phase. Consider internal energy equation for phase-1:
By combining equations of phases, we get internal energy balance for mixture in temperatures:
Where - latent heat of evaporation
- Linking liquid volume transport to pressure equation is done by introducing and at r.h.s of volume fraction balance equation. Then, replaced by value from pressure equation
- Phase change model
Schnerr-Sauer
2 Model Source Code For OpenFOAM 2.1.0
Source code for solver located here
3 Tutorial cases
- Case #1 - cavitation on the hemispherical body
Problem description, initial and boundary conditions are shown on the figure
- Case #2 - hot water flashing in the nozzle
Problem description, initial and boundary conditions are shown on the figure