CFD软件之phoenics

语言进行二次开发。

另一个

< br>CFD

软件

STAR-CD

的创 始人与

Phoenics

的创始人

Sp alding

都是英国伦敦大学同一教研室的教授，

他们的软件 的核心算法大同小异，

这里对

STAR- CD

就不做

详述。

< br>2.

PHOENICS

入门

< /p>

本文目的是帮助那些

PHOENICS

的 初学者在不需要深入了解该软件的情况下可以进行一些简单的流动计

算。

PHOENICS

界面包括模型编辑界面，数值计算 运行界面和计算结果查看界面三部分。

利用模型编辑界面来建 立几何模型是最适合初学者的，因为它不仅简单易懂，而且还可以自动生成

PHOENI CS

输入语言所编写的

Q1

文件而不用 使用者学习

PHOENICS

输入语言。当使用者对

有了一定的了解以后，可以利用

PHOENICS

输入语言直接编写

Q1

文件或利用

FORTRAN

语言更深入地编

< br>写一些模块。

计算结果查看界面可以将计算结果以形象 易懂地方式表现出来，

也可以利用

PHOENICS

将计算结果按我们想要的形式画出来，另外为了更好地观 察计算结果和提取有用信息可将计算结果进行格

式转换再用各种常用的图象处理软件处理 ，如

TECPLOT

，

ORINGE< /p>

，

MATLAB

等。

3.

模型编辑界面的控制面板图

一

.

.

4.

模型编辑界面的控制面板图

二

5.

计算结果查看界面的控制面板图

6.

模型 编辑界面和计算结果查看界面的通用界面图

CS

入门简介（英文版）

-1

正在读取此图片的详细信息，请稍候

...

INTRODUCTION TO PHOENICS

Contents

·

What PHOENICS does

·

The Structure of PHOENICS

·

How the problem is defined

·

How PHOENICS makes

the predictions

·

How the results are displayed

·

Hardware

·

Customization of PHOENICS

·

Learning to use

PHOENICS

·

The Virtual-Reality Interface

·

EARTH

·

GROUND

·

Built-in Features of EARTH

·

Display via

VR

·

PHOTON

·

AUTOPLOT

·

Other

Input

and

Output

Facilities

·

Programmability

·

PLANT

What

PHOENICS does

PHOENICS,

operated

by

its

users,

performs

three

main

functions:

m

definition,

in

which

the

user

prescribes the situation to be simulated and the questions to which he wants the answers; tion, by means of

computation,

of

what

the

laws

of

science

indicate

will PROBABLY

take

place

in

the

prescribed circumstances;

tation of the results of the computation, by way of graphical displays, tables of numbers, and other means.

PHOENICS, like many but not all CFD codes, has a distinct software module for each function. This sub-division

allows functions (1) and (3), say, to be performed on the user's home computer, while the power-hungry function

(2) can be carried out remotely.

The Structure of PHOENICS

·

PHOENICS has a

‘

planetary

’

arrangement, with a central core of subroutines

called EARTH, and a SA

TELLITE program,

which accepts inputs through the Virtual Reality (VR) interface or

otherwise,

which

correspond

to

a

particular

flow

simulation.

·

EARTH

and

SATELLITE

are

distinct

programs.

·

SATELLITE is a data- preparation program; it writes a data file which EARTH reads.

·

PHOENICS

users work

mainly

with SATELLITE, but they can access EARTH also in controlled ways.

·

GROUND is the

EARTH subroutine which users access when incorporating special features of their own. The diagram below is a

schematic

of

the

three

main

functions

of

PHOENICS,

i.e.,

-processor

-

problem

definition

-

simulation -processor - presentation of results

CS

入门简介（英文版）

-2

How the problem is defined

Problem

definition

normally

involves

making

statements

about:

·

geometry,

ie

shapes,

sizes

and

positions

of

objects

and

intervening

spaces;

·

materials,

ie

thermodynamic,

transport

and

other

properties

of

the

fluids

and

solids involved;

·

processes, for example:- whether the materials are inert or reactive; whether turbulence is to be

simulated and if so by what model; whether temperatures are to be computed in both fluids and solids; and whether

stresses in solids are to be computed;

·

grid, ie the manner and fineness of the sub-division of space and time, ie

what

is

called

the

and

·

other

numerical

(ie

non-physical)

parameters

affecting

the

speed,

accuracy

and

economy

of

the

simulation.

SPECIAL

FEA

TURES

of

problem

definition

which

distinguish

PHOENICS are:-

·

problem definition can be carried out in a V

ARIETY of ways, selected by the user according to

his experience or preference;

·

thus, engineers who use CAD packages can export the corresponding files directly

to PHOENICS-VR (ie Virtual Reality);

·

VR, and other interactive input procedures of PHOENICS, create as a

record a

themselves

the

tedium

(as

they

sometimes

see

it)

of

further

interactive

sessions;

·

the

feature

of

PHOENICS allows the property laws of new materials to be supplied by the writing of formulae into the command

file; and

·

hundreds of quality-assured command files are supplied with the standard PHOENICS sofware in a set

of easily accessible LIBRARIES, so that the user rarely has to start from scratch. PHOENICS has indeed its own

high-level input language, called PIL, in which the Q1 files are written.

PIL is a directly-interpreted language, requiring no compilation; and its capabilities include:

- direct assignment, as in:NX=10; CARTES=F (ie false); PI=3.1416

- interrogation, as in:NX?; CARTES? which print their values

- arithmetic commands, as in: NX=2*NY

- conditional settings, as in: IF(.10) THEN; CARTES=F; ENDIF

- DO loops, as in: DO II=1,3

MESG(Three cheers! HURRAH! ENDDO

- INCLUDE commands, as in: INCL(file name

- LOAD commands, as in:L(library case number

- numerous other facilities for setting grids, boundary and initial conditions, material properties, output needs and

other data.

So far as is known, PIL is the most powerful and flexible input language ever devised for the setting up of CFD

problems.

How PHOENICS makes the predictions

PHOENICS

simulates

the

prescribed

physical

phenomena

by:-

·

expressing

the

relevant

laws

of

physics

and

chemistry,

and

the

which

supplement

them,

in

the

form

of

equations

linking

the

values

of

pressure,

temperature, concentration, etc which prevail at clusters of points distributed through space and time;

·

locating

these

point-clusters

(which

constitute

the

computational

grid)

sufficiently

close

to

each

other

to

represent

adequately

the

continuity

of

actual

objects

and

fluids;

·

solving

the

equations

by

systematic,

iterative,

error-reduction methods, the progress of which is made visible on the VDU screen;

·

enabling the computations to

be interrupted, and the controlling settings to be modified, as the user desires;

·

terminating when the errors have

been

sufficently

reduced.

SPECIAL

FEATURES

relating

to

how

PHOENICS

makes

the

predictions

are:

·

PHOENICS can handle a WIDER RANGE OF PHYSICAL PROCESSES, and is equipped with a MORE

EXTENSIVE

V

ARIETY

OF

PHYSICAL

MODELS,

than

any

of

its

competitors.

·

The

ways

in

which

these

physical processes are represented in the computer language, Fortran, are visible and accessible to users, and NOT

hidden as in most other codes. The relevant coding, called GROUND, constitutes more than fifty percent of the

EARTH

module.

·

This open-source coding is written in a well-annotated easy-to-follow

manner, in order that

users can, if they wish: ounderstand, odecide whether CHAM's provision meets their needs, and oeither modify it

or add coding of their own.

·

For users who are not confident of their ability to do this, CHAM has provided the

PLANT option, which reduces the user's duties to entering the required formulae into the command file.

·

Unlike

those other CFD codes which cope with geometrical complexity by the use of

retains

the

computational

economy

of

the

more-orderly

GRIDS

while

utilising

complexity.

·

A related and unique feature is the MOVSOL, feature, which makes it easy, economical and accurate

to allow curvilinear solids to move relative to each other across curvilinear grids.

·

PHOENICS possesses a unique

EXPERT

feature,

which

automatically

optimises

the

numerical

parameters

as

the

computation

proceeds.

·

PHOENICS also employs an economical and unique-to-it

very

common

character.

·

The

PHOENICS

grid

has

lent

itself

particularly

well

to

PHOENICS can display the results of its flow simulations in a wide variety of forms.

It

has

its

own

stand- alone

graphics

package

called

PHOTON;

and

it

can

also

export

results

to

such

third-party

packages as TECPLOT, A

VS, and FEMVIEW.

Unique

to

PHOENICS

is

its

ability

to

take

the

results

of

its

flow

predictions

back

into

the

same

VIRTUAL-REALITY environment as is used for setting up the problem at the start.

This

facilitates

understanding

by

the

user;

and

it

also

affords

a

means

of

conveying

the

significance

of

the

flow-simulation operation to interested but non-technical persons, eg. high-level managers.

Of course, numerical results are also provided, in the RESULT , when the appropriate commands in the

Q1 file, can provide either sparse or voluminous information.

CS

入门简介（英文版）

-3

The Virtual-Reality Interface

Data input via the VR-Editor

The Virtual-Reality user interface assists users to set up flow-simulation calculations, without having to learn the

PHOENICS Input Language. In this data- input mode, it is called the VR-Editor.

The appearance of VR-Editor the screen is shown on the next suffices therefore to say here that objects of

all kinds (blockages, inlets, outlets, sources, etc) can be

brought in by appropriate mouse-clicks, and then given

such locations, shapes, sizes, materials and other attributes as are needed to start the flow-simulating calculation

CS

入门简介（英文版）

-4

This is the top part of the menu which appears when the Main Menu button is pressed. It enables whole-domain

settings to be made.

What the Virtual-Reality Editor creates

The VR-Editor records the settings made by the user during his editing session in an ASCII file known as Q1.

This file can be read, understood (if the user knows something of PIL, the PHOENICS Input Language) and edited.

Usually, however, it will simply be stored for later use.

In any case, the flow-simulation can begin immediately, if the user wishes, because two other files will also have

been automatically written, one of which (FACETDAT) conveys the necessary geometrical information, while the

other (EARDAT) carries everything else that the solver module needs to know.

The switching from the VR-Editor to the solver, and for that matter to any other PHOENICS module, is rendered

particularly easy by the pull-down menus accessible from the top bar of the VR-Editor screen

CS

入门简介（英文版）

-5

EARTH The solver EARTH starts with a MAIN program, open to users for re-dimensioning operations.

The

other

user- accessible

source

subroutines

are

GROUND,

GREXn

(i.e.,

GROUND

example,

number

n)

and

others of the same kind.

EARTH contains sequences for:

·

storage allocation

·

formulation of finite- volume equations

·

iterative solution

of finite-volume equations

·

calling GROUND when required

·

termination of iteration sequences

·

output of

results A Typical EARTH Convergence Monitor Plot

GROUND GROUND is a subroutine which is called by EARTH at pre-set points of the solution cycle. If the user

inserts appropriate FORTRAN statements at the entry points in GROUND, EARTH absorbs these into the solution

process.

Special communication subroutines allow the user to extract information from EARTH, manipulate it in GROUND

and then return new information or instructions to EARTH.

Many

sub-routines

are

attached,

performing

commonly-needed

arithmetic

operations.

These

greatly

reduce the user's need to write FORTRAN-coding sequences.

Built-In Features Of EARTH

Conservation

principles

PHOENICS

sets

up

and

solves

finite-domain

equivalents

of

the

basic

differential

equations.

It

thus

embodies

the

laws

of

conservation

of

mass,

momentum

and

energy,

for

either

one

or

two

phases.

More- than-2-phase flows can also be represented in a number of ways.

Any

property

obeying

a

balance

equation

can

be

represented,

including

·

species

concentration,

·

turbulence

energy,

·

vorticity and its fluctuations

·

radiation fluxes,

·

electric potential, etc. Solution procedures PHOENICS

contains

solvers

for

sets

of

linear

simultaneous

equations.

Options

include:

·

point- by-point,

·

slab-wise,

and

·

whole-3D-field. The coupled hydrodynamic equations are solved by the so-called SIMPLEST procedure.

For two-phase flows, the IPSA version of this is used. Details of these procedures are given in the published CFD

literature.

Handling

special

requirements

EARTH

can

handle

problems

which

are:

·

steady

or

unsteady,

·

parabolic

or

elliptic,

and

·

0D,

1D,

2D

or

3D.

EARTH

accepts

grid-definition,

material- property,

initial-value

and

boundary-condition information transmitted from the satellite.

EARTH turns to GROUND (or GREXn. etc.) for further data settings, when so instructed.

EARTH arranges for print-out of required output, and also of warnings, diagnostics, etc.

What

is

not

built-in

Turbulence-model,

chemical-kinetic,

interphase-transport,

radiation-flux

and

other

coding

sequences are attached, through GROUND, to the outside of EARTH.

They can therefore be inspected, modified or replaced by the PHOENICS user.

The built-in solvers can also be inspected, modified and replaced, should the user desire.

EARTH is thus a

CS

入门简介（英文版）

-6

Display via VR

The

Virtual-Reality

Interface

of

PHOENICS

can

also

operate

as

a

results-display

device.

It

is

then

called

the

VR- Viewer.

A Typical VR-ViewerPlot

The

main advantage of VR- Viewer over the older PHOTON program is the ease with which it enables users to

view streamlines, vectors, iso-surfaces and contour plots.

However, it does not yet possess, as PHOTON does, a command language in which

the repetition of frequently- required operations.

CS

入门简介（英文版）

-7

PHOTON

A further menu-driven interactive program, called PHOTON, can create from PHOENICS output:

·

grids, and grid

outlines

·

contour plots, in either colored-line or filled area modes

·

streamlines, in any color

·

vector plots, for

either of the two phases

·

surface plots

·

magnified views of parts of the field

·

arbitrarily chosen view-points in

multiple windows A Typical PHOTON Plot

CS

入门简介（英文版）

-8

AUTOPLOT

AUTOPLOT is the second member of the PHOENICS graphics family. It is a command-driven which can:

·

plot

x-y graphs from

any combination of PHOENICS output files, and user- supplied data files. This allows for easy

comparison of PHOENICS solutions with experimental or analytical data.

·

manipulate the data in a number of

ways, such as adding or subtracting constants, multiplying or dividing by constants, raising to powers, taking logs

and

antilogs,

and

many

more.

·

The

data

can

be

presented

in

a

number

of

line

styles.

A

Typical

AUTOPLOT

Picture

CS

入门简介（英文版）

-9

Other Input and Output Facilities Many more input and output features of PHOENICS can be operated from the

satellite.

Users

for

whom

the

built-in

facilities

do

not

suffice

may

introduce

their

own

input/output

sequences

via

the

FORTRAN of SATLIT and GROUND.

GROUND-located

sequences

for

problem-specific

input,

output

source

terms,

boundary

conditions

or

physical

properties are switched on by setting special flags in the satellite.

An exemplary GROUND, subroutine GREXn, contains many frequently-used settings.

When

these

do

not

suffice,

the

task

of

creating

new

ones

is

lightened

by

provision

of

numerous

auxiliary

sub-routines, into which users need merely to supply the arguments.

Programmability

User- accessible Fortran

PHOENICS is designed to serve two kinds of user: those who wish to perform flow simulations of standard kinds,

with

standard

fluids,

and by

standard

methods;

and

those

whose

needs

or

intentions necessitate

the

addition,

in

user-accessible subroutines, of special FORTRAN-coding sequences.

For users of the second kind, the so-called GROUND subroutines are supplied as part of the EARTH module. The

PHOENICS

Encyclopaedia

contains

full

information

about

how

these

are

accessed,

inspected,

modified

and

augmented.

The description explains how PHOENICS stores its data in memory, in the so-called F-array; and it does so in such

detail

that

it

is possible

for

the diligent

enquirer

to

intervene

not

only

in

the

physical

modelling but

also in

the

numerical-solution procedure.

The

access

to

GROUND

coding

also

allows

the

introduction

of

calls

to

non- PHOENICS

software

modules

or

data-bases, and the provision of special print-out sequences.

For the

convenience of

the user who

wishes to

create Fortran

coding of

his

own, PHOENICS

is equipped

with

many

subroutines;

these

perform

the

most-commonly-required

arithmetic,

algebraic

and

print-out

operations, so that it is rarely necessary for the user to do more than assign the arguments and call the functions.

The use of these facilities is amply illustrated in the exemplary subroutines which constitute the built-in modelling

features of PHOENICS.

Examples are also to be found in the pages of the PHOENICS Journal.

For those users who want the benefits of the programmability of PHOENICS but are too uncertain of their Fortran

skills to obtain them directly, the PLANT feature, described in the next section, provides them with what they need.

CS

入门简介（英文版）

-10

What is PLANT

?

PLANT is an integral part of the PHOENICS SA

TELLITE which permits users to place in their Q1 files formulae

for

which

there

may

not

be

any

existing

counterpart

in

EARTH

or

GROUND.

PLANT

then

converts

these

formulae

into

error-free

Fortran

coding

which

is

into

the

GROUND

sub-routine

at

the

right

place;

thereafter compilation, re-linking and execution take place automatically.

In

this

way,

PLANT

relieves

the

user

of

the

tasks

of:

·

writing

the

Fortran;-

placing

it

correctly

in

GROUND;

·

compiling;

·

re-linking;

·

initiating the EARTH run. All the user needs to learn is a few simple rules

about the format to be used for writing the formulae in the Q1 file.

How to learn about PLANT

A convenient way to learn about PLANT is to inspect the examples in the appropriate section of the PHOENICS

input-file library. It is divided into sections dealing, among other topics, with:

·

Non-linear property correlations *

Inter-phase-transport law

·

Field initialisations * Sources

·

Print-out preparations * Validation tests

·

Consistency

tests * Conjugate heat transfer

·

Two-phase flows * Natural and mixed convection

·

Chemical-reactive flows *

Equipment-oriented cases

·

Environmental studies * Numerical techniques

·

Non- linear flow resistances * Flame

propagation

·

Vents linked to heat detectors * Stress-in-solids examples

·

Grids, fixed and adaptive * Multi-fluid

turbulence Why PLANT is useful

The advantages of the PLANT facility are numerous. They include:-

·

The formulae can be created or modified

more swiftly, read more easiliy, and stored more compactly, in the Q1 file than in the GROUND Fortran.

·

The

programmability of PHOENICS can therefore be exploited easily by persons who have no knowledge of Fortran

programming, and who have not learned how to compile the resulting coding and to re-build executables.

·

Those

users

who

do

possess

the

knowledge

and

experience

of

coding,

compiling,

linking,

etc,

can

nevertheless

save

themselves

much time by using

PLANT.

·

The

following diagram shows how, before PLANT, the user had to

perform TWO operations to introduce new coding into EARTH.

/E

与

PH OENICS

的传输

Pro/E < /p>

模型传到

Phoenics

的具体步骤如 下：

1.

< br>将建好的

Pro/E

零件实体图或装配实体图存成

STL

文件

格式。

Pro/E

中的步骤为：

(1).

主菜单上

File- Export-Model,

选

STL

格式，注意：

STL

菜单中

form at

选

ASCII,

不能选