Phoenics Features

It continues to be heavily used for these purposes.

PHOENICS can handle the combustion of gaseous, liquid (e.g. oil-spray) and solid (eg pulverized-coal) fuels.

Chemical reactions are simulated by PHOENICS in several ways, including:

• SCRS, "the Simple Chemically Reacting System" built into user-accessible Fortran coding (which users may modify, but need not even look at);
• ESCRS, "the Extended Simple Chemically Reacting System" built into user-accessible Fortran coding;
• CREK, a set of user-callable subroutines which handle the thermodynamics and finite-rate or equilibrium chemical kinetics of complex chemical reactions;
• CHEMKIN 2, the public-domain code to which PHOENICS has an interface,
• PLANT, which enables users to introduce new reaction schemes and material properties by way of formulae introduced into the data-input command file, Q1.

Explosion in a baffled enclosure

Thermal radiation is so important a mode of heat transfer that most codes have some means of simulating it. Only PHOENICS however possesses the economical and realistic IMMERSOL model, which calculates the radiative transfer between arbitrarily-shaped solids immersed in fluids which may or may not themselves emit and absorb radiation.

• steam and water in a boiler,
• air and sand in a desert storm,
• fuel droplets and combustion gases in an engine,
• a layer of oil, floating on the surface of a river.

PHOENICS was the first general-purpose computer code to be able to simulate multi-phase flows; and it is still capable of doing so more effectively, and in a greater variety of ways, than most of its competitors.
Multi-phase-flow phenomena can be simulated by PHOENICS in four distinct ways. These are:

a. as two inter-penetrating continua, each having at every point in the space-time domain under consideration, its own:
velocity components, temperature, composition, density, viscosity, volume fraction, etc; IPSA (Eulerian-Eulerian method)
b. as multiple inter-penetrating continua having the same range of properties; (Algebraic Slip Method (Mixture method)
c. as two non-interpenetrating continua, separated by a free surface; (Scalar Equation Method (VOF TVD type method)
d. as a particulate phase for which the particle trajectories are computed as they move through a continuous fluid. (Eulerian - Lagrangian type method).

Multiphase flows

• LAMINAR - The flow is laminar and there is no turbulence model.
• CONSTANT-EFFECTIVE - The turbulent viscosity is constant. The default setting is 200 times the laminar viscosity.
• LVEL - Generalised length-scale zero-equation model, useful when there are many objects and the grid is coarse.
• KEMODL - Classical two-equation high Reynolds number. k-e model
• KOMODL - Kolmogorov-Wilcox two- equation k-f model. Useful for transitional flows and flows with adverse pressure gradients.
• USER - User-defined model for advanced users.

• KE Variants - Several variants of the K-E model usually giving enhanced performance for recirculating flow.
  • KECHEN - Chen-Kim two-equation k-e model. Gives better prediction of separation and vortexes.
  • KERNG - RNG derived two-equation k-e model. Gives better prediction of separation and vortexes. However, the user is advised that the model results in substantial deterioration in the prediction of plane and round free jets in stagnant surroundings.
  • KEMMK - Murakami, Mochida and Kondo k-e model for flow around bluff bodies as encountered for example in wind-engineering applications.
  • KEKL - Kato-Launder k-e model for flow around bluff bodies as encountered for example in wind-engineering applications.
  • KEMODL-YAP - k-e model with Yap correction for separated flows.
  • TSKEMO - Two scale k-e model for flows in which there is an appreciable time lag between the turbulent production and dissipation processes.
• Low-Re models - Several Low-Reynolds Number variants of the K-E model.
  • KEMODL-LOWRE - Lam-Bremhorst low Reynolds version of k-e.
  • KEMODL-LOWRE-YAP - Lam-Bremhorst low Reynolds k-e with Yap correction for separated flows.
  • KECHEN-LOWRE - Low Reynolds variant of Chen-Kim model.
  • KEMODL-2L - Two layer k-e model, which uses the high-Re k-e model only away from the wall in the fully-turbulent region, and the near-wall viscosity- affected layer is resolved with a one-equation model involving a length-scale prescription. This saves mesh points and improves convergence rates.
  • KOMODL-LOWRE - Low Reynolds Kolmogorov-Wilcox model.
• Others- A range of models, from simple one-equation models to Reynolds Stress (REYSTRS), including a Sub-Grid-Scale LES model (SGSMOD).
  • MIXLEN - Prandtl mixing-length model. Simple model for unbounded flows.
  • MIXLEN-RICE - Mixing-length model for bubble-column reactors.
  • KLMODL - Prandtl energy model. One-equation k-l model for wall-dominated flows.
  • KWMODL - Saffman-Spalding two-equation. k-vorticity model
  • REYSTRS - Reynolds stress model
  • SGSMOD - Smagorinsky sub-grid scale LES model with wall damping
  • SGSMOD_NOWD - Smagorinsky sub-grid scale LES model with no wall damping
  • SGSMOD_VDWD - with Van Driest wall damping function
  • 2FLUID - Two-fluid model
  • MFLUID - Multi-fluid model

• its own large library
• CAD packages
• its own solid-modelling package, Shapemaker,
• the powerful bundled-with-PHOENICS package.

Once imported, the objects can be moved, stretched, rotated, duplicated, grouped, given, attributes, hidden, deleted, etc. By default, after the objects have been placed in the desired positions, the grid adjusts itself to fit them optimally. Very often, CFD analysis is required for a situation which has been already defined geometrically by way of a Computer-Aided-Drawing (CAD) package.

If the geometry already exists as CAD geometry files, a considerable time saving can be achieved through the use of PHOENICS-VR's ability to import CAD files directly.

CAD-packages are frequently used to design engineering equipment. Most have the ability to define their output in a variety of formats. The formats supported directly by VR are:

Many further formats are supported indirectly by translation to .3ds using SimLab Composer from SimLabSoft. This software is shipped with PHOENICS and runs silently whenever required. A licence key can be obtained directly from CHAM. The formats requiring Simlab Composer are:

PHOENICS VR converts the CAD file to the PHOENICS-VR geometry format directly (or indirectly via SimLab) using the Datmaker utility. Below is shown an example of residential buildings displayed in the VR-Editor. The CAD file was created by way of the well-known AUTOCAD package. This CAD file in STL format was polished by PHOENICS, and then imported into PHOENICS-VR in a few seconds, rotated, and somewhat re-sized.

buildings from CAD

(1) introducing new variables, for example the temperatures in each part of the intersected cell, and

(2) providing equations from which their values can be deduced.

PARSOL is capable of calculating the fluid-flow phenomena with improved accuracy, whether the flow is laminar or turbulent, and whether heat transfer is present or absent. Accuracy of simulation often requires that the computational grid should be very fine around regions of the domain exhibiting steep gradients of temperature, concentration, density or other significant fluid property. In earlier versions of PHOENICS, this entailed also extending the fineness into regions where it was not required.

Fine-grid embedding, now available, renders this unnecessary; for it is possible to refine the grid ONLY where necessary.

fine grid embedding around a car

Cut & cell technique