PHOENICS provides an accurate, reliable, cost-effective, and easy-to-use tool to simulate processes involving fluid flow, heat or mass transfer, chemical reaction and/or combustion in engineering equipment and the environment. With the longest history of validation and a large user base, it is not surprising that PHOENICS has a proven track record in nearly every branch of science and engineering in which fluid flow plays a key role. Organizations large and small use PHOENICS to improve their competitive edge in the research and development of products and processes involving fluid flow and heat transfer.
- Problem dimensionality: one, two and three dimensions.
- Time dependence: steady state and transient processes.
- Grid systems: Cartesian, cylindrical-polar and curvilinear co-ordinates; rotating co-ordinate systems; multi-block grids and fine grid embedding.
- Compressible/incompressible flows.
- Newtonian/non-Newtonian flows.
- Subsonic, transonic and supersonic flows.
- Flow in porous media, with direction-dependent resistances.
- Convection, conduction and radiation; conjugate heat transfer, with a library of solid materials and automatic linkage at the solid fluid interface.
- A wide range of built-in turbulence models for high and low-Reynolds number flows; LVEL model for turbulence in congested domains and a variety of K-E models, including RNG, two- scale and two-layer models.
- Multi-phase flows of three kinds with a variety of built-in interphase-transfer models:
- Inter-penetrating continua, including turbulence and modulation;
- Particle tracking, including turbulence dispersion effects;
- Free-surface flows.
- Finite-volume approach on staggered or collocated grids, with 13 choices of discretization schemes for convection.
- Combustion and Nox models, with a range of diffusion and kinetically controlled models including the unique Multi-Fluid Model for turbulent chemical reaction.
- Chemical kinetics including multi-component diffusion and variable properties. Built-in interface to the CHEMKIN chemical database.
- Advanced radiation models, including surface-surface model with calculated view factors, a six-flux model and composite radiosity model for radiative heat transfer, known as IMMERSOL
- Mechanical and thermal stresses in immersed solids can be computed at the same time as the fluid flow and heat transfer.
From its beginning in 1981, PHOENICS has been used for simulating processes involving chemical-reaction processes, and especially those involving combustion.
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.
Multi-phase flows are those involving, to name but a few examples:
• 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).
There exist many well-established computer codes for stress-analysis only; and PHOENICS is not proposed as a replacement for them. However, if fluid-flow, solid-stress and thermal interactions are all of significance, PHOENICS is the only computer code which can handle them all simultaneously.
Fluid structure Interaction
The available turbulence models, in PHOENICS, are divided into the following groups:
- 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
The Graphical User Interface of PHOENICS facilitates the import of objects from:
- 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:
||Stereolithography file. This is available in many popular CAD programs as an export format. ASCII and binary forms are supported.
||Autodesk 3ds Max (3D Studio)
||Virtual Reality Modelling Language file
||Files generated by DesignWorkshop from Artifice
||Files generated by AC3D from Invis
||Files generated by Open Inventor
||Native OSG (OpenSceneGraph) ascii
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:
||AutoCAD Drawing Exchange Format file
||AutoCAD Drawing Database file(3D)
||AutoCAD Design Web Format file
||SolidWorks assembly and parts files
|*.asm, *.par, *.psm
||SolidEdge assembly and parts files
||IGES (Initial Graphics Exchange Specification) file
||Autodesk Inventor assembly and parts files
||3D ACIS Modeler - Standard ACIS Text file
||Wavefront Technologies geometry definition file (OBJ)
|| Extensible Application Markup Language XAML file
||3DXML - Dassault Systemes 3DVIA file
||Universal 3D file
||COLLADA Digital Asset Exchange file
||Autodesk FBX Technology file
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
MOFOR is a feature of PHOENICS, which permits the simulation of flows induced by bodies in motion.It acts by moving, through the fixed computational grid, such momentum sources as will ensure that the velocities at locations within the body have the values implied by the prescribed motion. There is another important class of phenomena in which fluids are caused to move by motions imparted to the domain itself. A familiar example is the 'sloshing' of a layer of liquid in a tank which is jolted, tilted, or caused to oscillate. Such motions can also be handled by MOFOR.
PARSOL is the technique in PHOENICS for improving the accuracy of flow simulations for situations in which a fluid/solid boundary intersects obliquely some of the cells of a cartesian or polar-coordinate grid by:
(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
PHOENICS PLUS (FORTRAN coding) allows users to create customized environments to suit specific needs. Where an organization does not have the resources, or inclination, to undertake development our consultants will use PHOENICS PLUS to carry out the necessary work. If problems involve unique or ground-breaking physics this may not be included in the core of PHOENICS. PHOENICS PLUS allows new physics to be added to augment or replace standard definitions. IN-FORM achieves this on a case-by-case basis whereas additions made using PHOENICS PLUS are available for all cases. In-Form is a supplement to the PHOENICS Input Language which facilitates the input of problem-defining data. Specifically, it allows users to express their requirements through algebraic formulas, whether for:
• space and time discretization,
• material properties,
• initial values,
• boundary conditions,
• body shapes and motions, or
• Special print-out features.
There are two principal reasons for using parallel rather than sequential PHOENICS. They are:
- to obtain computational results in a shorter time, and
- to use finer grids than a single processor permits.
The parallel solver shares the computational domain and task between a number processors; each processor then performs the computations for its part of the domain simultaneously. Thus the whole task may be achieved in a shorter time.
In theory, the more processors used, the shorter the computer time will be. The following table shows the speed-up achieved when carrying out computations on a model with 20 million cells.
It can be seen that there is not a linear relationship between the number of processors and the speed-up ratio. This is because for each additional processor added to the computation pool, there is an additional overhead. Eventually a limit will be reached whereby adding additional processors does not lead to a faster solution time. What this limit is depends on the computational domain under consideration.
Post-processing tools for PHOENICS can be used to generate all graphics and animations for fluid dynamics results. Phoenics output results are available under various formats for:
VR-VIEWER (PHOENICS Post-Processor)
• Monthly, Annual or Perpetual
• 32-bit & 64 bit sequential- or parallel-processing
• Windows or Linux
• Standard 3 day training course
• Day rate for consultancy and model build
• Extended consultancy support