CFD Online Discussion Forums - Derivative of two volScalarFields

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Derivative of two volScalarFields

Hello,

I am trying to implement the Homogeneous Relaxation Model (HRM) of Downar-Zapolski (1995) in interPhaseChangeFoam.
Currently I am struggling with the pressure equation and explicitly the derivative of two volScalarFields $\frac{\partial \rho}{\partial \alpha}$ which is the derivative of the density to the phase fraction alpha.
Is there already a built in function in OpenFoam or do I have to write my own method for this?
I could not find anything on the forum or in the manual. All gradients I found are only gradients in space.

The derived pressure equation is:
$\rho \nabla \cdot \left(\frac{\nabla p}{a_p}\right) - \rho \nabla \cdot \left(\frac{H(U)}{a_p}\right) = \left(\frac{\partial \rho}{\partial \alpha}\right)_{p,h} \underbrace{\left( -\alpha \frac{h_\mathrm{ML}(p,T)-h_\mathrm{SL}(p)}{h_\mathrm{SG}(p)-h_\mathrm{SL}(p)}\frac{1}{\Theta}\right)}_{\frac{\mathrm{D}\alpha}{\mathrm{D}t}}$

This pressure equation can also be found in the work of Lee et al. (Flashing flow of superheated jet fuel) and Schmidt (Multi-dimensional simulation of thermal non-equilibrium channel flow)

Hello,

Were you able to figure out the implementation of HRM in openfoam?

If yes, Could you please help me out to find the model?

Thank you
Neel Shah

Hello,

yes I have implemented the HRM model. You can find further details in the following publications. Possibly I will publish my code in the future too.
DOI: 10.1016/j.ijmultiphaseflow.2020.103360DOI: https://doi.org/10.3390/fluids6030104

Best,

Jan

So, No one has published the HRM code for Openfoam?

Can you help me with any other that works best for Cryogenic Fluid, please?

Thank you

Hello!

I am doing some related work in flash boiling gasoline spray, and have captured the shock waves in flash boiling jets under wide thermodynamic conditions. The HRM model in CONVERGE is used in my work, but there are some problems, and I'd like to do some comparative work. Is your Foam open source now?

Best

Lubing Xu

Hello,

the code is unfortunately not publicly available that you can just download it. However, if you are interested in it please send me an e-mail and we can see if we can grant access to it.

jan-wilhelm.gaertner@itv.uni-stuttgart.de

Best,

Jan

I will send the email soon. Is your numerical case a 2D simulation in the work Numerical and experimental analysis of flashing cryogenic nitrogen?

Best!

Lubing

So, No one has published the HRM code for compete in online plinko tournaments Openfoam?