New heterogeneous reacting cloud functionality has been added to the Lagrangian library. This cloud is initially formed of a single solid component which reacts with the gas phase to create a solid product in the particles through a reaction of the type
The initial particle composition is specified in the reactingCloud1Properties dictionary:
- Source code
- D. Papanastassiou and G. Bitsianes, Modelling of Heterogeneous Gas-Solid Reactions, Metallurgical Transactions, 480. Volume 4. 1973
The isoAdvector geometric Volume of Fluid method used by the interIsoFoam solver has been extended to work with morphing meshes. This is useful for a wide range of applications, e.g. generation of realistic water waves by moving domain sidewalls.
The following video shows a surface that correctly remains flat (calm) under the action of a moving mesh.
- Source code
- Known issues
- The current implementation should only be used with the Euler ddtScheme in the fvSolution dictionary
- The code extension was provided by Johan Roenby, STROMNING
- The calmWater tutorial was provided by Zhaobin LI, Ecole centrale de Nantes
- Expanded MULES/CMULES interfaces to incorporate templated arguments for psiMax and psiMin.
- Reworking and expansion of the framework for species thermodynamic to handle internal energy (e) consistently.
- Incorporation of population balance model in the phase system for multi-phase Euler solvers.
- Incorporation of alphatWallBoilingWallFunction to handle the sub-cooling nucleating boiling regime
The new overBuoyantPimpleDyMFoam solver adds overset capabilities to the buoyantPimpleFoam solver.
- Source code
The new chtMultiRegionTwoPhaseEulerFoam solver combines the functionality of reactingTwoPhaseEulerFoam and chtMultiRegionFoamfor solving solid/fluid coupled systems. Region interfaces are coupled using the turbulentTemperatureTwoPhaseRadCoupledMixed boundary condition.
Transitional and film boiling regimes now complement the earlier single phase and nucleating boiling regimes available in the alphatWallBoilingWallFunction boundary condition to model the heat transfer coefficient for boiling flows in general.
The wall function uses a partition method to transfer heat either to the liquid or vapour phase. Currently this function works in a fixed wall temperature mode. i.e, there is no consideration for the sudden change of heat transfer coefficient (burn out) after reaching the deviation from nucleate boiling temperature, . See Srinivasan et al. (2010).
For the single phase non-boiling regime the standard Jayatilleke wall function is used. For the sub-cooled nucleate boiling regime the following run-time selectable sub-models are available:
- nucleation site density
- bubble departure frequency
- bubble departure diameter
This is based on a version of the well-known RPI wall boiling model (Kurul and Podowski, 1991). The implementation is similar to the model described by Peltola and Pattikangas (2012) but enhanced with the wall heat flux partitioning models.
The transition boiling regime flux () is modelled following a temperature based linear interpolation between the Critical Heat Flux () and the Minimum Heat Flux () in such a way that when the wall temperature is between the range of Deviation From Nucleate Boiling () and the Leidenfrost Temperature () a linear interpolation is used between and .
The following models are required:
- Leidenfrost Temperature Model
- SubCool Model
- Film Boiling Model
The linear interpolation is as follows for the TBF regime is calculated as:
where is a model constant (default 1) and the wall temperature. The film boiling regime is applied when is larger than . In this regime the correlation from the film Boiling Model is used for calculating the cht from the wall.
The sub-cooled model modifies when sub-cooled conditions are present. The following sub-models are implemented:
- Critical heat flux (CHF) correlation. See Zuber (1958)
- Film Boiling Model. See Bromley (1950)
- Minimum heat flux (MHF) model. See Jeschar et. al. (1992)
- Leidenfrost temperature model. See Spiegler et. al. (1963)
- Critical heat flux for Sub-Cool boiling flows. See Hua and Xu (2000)
- Departure from Nucleate Boiling Correlation. See Thelera and Freisba ()
- Source code
- Numerical simulation of immersion quenching process of an engine cylinder head Vedanth Srinivasan, Kil-Min Moon, David Greif, De Ming Wang, Myung-hwan Kim. Applied Mathematical Modelling 34 (2010) 2111-2128
- On the modeling of multidimensional effects in boiling channels, Kurul, N., Podowski, M.Z., ANS Proceedings, National Heat Transfer Conference, Minneapolis, Minnesota, USA, July 28-31, (1991)
- Development and validation of a boiling model for OpenFOAM multiphase solver, Peltola, J., Pattikangas, T.J.H., CFD4NRS-4 Conference Proceedings, paper 59, Daejeon, Korea, September 10-12 (2012)
- A. Bromley, Heat transfer in stable film boiling, Chem. Eng. Prog. 58 (1950) 67-72.
- N. Zuber, On the stability of boiling heat transfer, Trans. ASME 80 (1958) 711
- Jeschar, E. Specht, C. Kohler, Heat Transfer during Cooling of Heated Metallic Objects with Evaporating Liquids, Theory and Technology in Quenching, Springer, (1992). Chapter 4.
- Spiegler P., Hopenfeld J., Silberberg M., Bumpus J. and Norman A., Onset of stable film boiling and the foam limit, International Journal of Heat and Mass Transfer, 6,11, pp.987-989, (1963)
- T.C. Hua, J.J. Xu, Quenching boiling in subcooled liquid nitrogen for solidification of aqueous materials, Mater. Sci. Eng. A 292 (2000) 169-172.
- Theoretical Critical Heat Flux Prediction Based Non-Equilibrium Thermodynamics Considerations The Subcooled Boiling Phenomenon Thelera G. and Freisba D.. TECNA Estudios y Proyectos de Ingeniera S.A. Encarnacion Ezcurra 365, C1107CLA Buenos Aires, Argentina Westinghouse, Electric Germany GmbH, Dudenstrasse 44, 68167 Mannheim, Germany
The solar load model now incorporates reflecting radiative fluxes, enabling reflections to be calculated on specular surfaces.
Reflection effects are enabled by the new useRefectedRays entry in the radiationProperties dictionary, i.e.