$$$$ ENCEINTE NOTICE CHAT 11/09/12 21:16:01 7124
DATE 11/09/12
Procedure ENCEINTE Voir aussi :
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ENCEINTE NDT RXT ;
NDT ENTIER : Number of time steps
RXT TABLE : containing the problem description
Description :
_____________
The ENCEINTE procedure computes, from an initial state, the evolution
in time of a gazeous mixture in a closed containment.
The initial state can either be a uniform state or the result of a
previous computation.
The gazeous mixture is basically composed of air but it can contain
one or several gases like: steam ,H2,N2,He,O2,CO,CO2.
In presence of steam wall condensation can occur if locally conditions
are satisfied: Pvap > Psat.
The wall condensation model is a Chilton-Colburn type using a free
convection correlation.
We make out 3 types of boundary conditions: the injection zones
(leak), walls and symetry planes.
- The injection zones (possibility of three zones) are surfaces of
prescribed values. It concerns the velocity, the mixture temperature,
air and all other constitutive gases if they are present: steam,H2,N2,
He,O2,CO,CO2. It is necessary to specify the mass flow rate for the
mixture (Kg/s), the inlet temperature (°C) the mass flow rate for air
and each present gases function of time (see table entry 'scenario').
- Walls :
- Thermal walls : The velocity is set to zero. The temperature is either
prescribed in time (entry TIMP1), set at an initial value which can be
modified after by personnal procedure (ECHANP) or the result of a thermics
computation (entry THERMP). It is possible to couple thermal equations for
walls and the flow in an implicit way (entry THERCO).In presence of steam
these walls are able to condense steam. They are impermeable for all
incondensable gases.
- Passive walls. The velocity is set to zero, and the walls are
adiabatic/impermeable for all other unknowns (temperature steam and
incondensable gases). Actually it is the only way to impose symetry plane.
They are obtained by difference between the meshes:
Envelope - walls - breaks.
The turbulent motion of the mixture is modeled either with a constant eddy
viscosity model, or a length scale model, or a K-Epsilon model (entry MODTURB)
Absence of entry MODTURB means : the flow is laminar.
A Spray model is avaliable.
The preparation of a computation consists to fill entries of the
RXT table and then call the ENCEINTE procedure with this table.
Entries and their meaning are following :
rxt = TABLE ; Contains the description of the problem.
This table is achieved with three tables GEO TBT TIC
when the ENCEINTE procedure is executed.
The sub-table GEO contains all the objects concerning the geometry
created from the data.
The sub-table TBT is a work table and contains all the objects needed
for the computation except the unknowns and the geometry
The sub-table TIC contains all the unknowns and is used to, restart a
computation.
!!! The entries of the table RXT given by the user are not modified.
I/ Definition of geometrical objects
------------------------------------
rxt.'vtf' = MAILLAGE ; Definition of fluid mesh (mandatory)
rxt.'breche' = MAILLAGE ; Mesh of the break
rxt.'diru1' = POINT ; Direction of the injection velocity.
rxt.'pi' = POINT ; Definition of a point inside the fluid
domain which will be used to prescribe the
pressure (mandatory).
rxt.'axe' = MAILLAGE ; axe if 2D AXI
< rxt.'breche2' = MAILLAGE ;> Second break
< rxt.'diru2' = POINT ;> Direction of the injection velocity
(second break)
< rxt.'breche3' = MAILLAGE ;> Third break
< rxt.'diru3' = POINT ;>
II/ Physical models.
--------------------
A/ Wall thermics
----------------
rxt.'THERMP' = 'LOGIQUE' ; VRAI if wall thermics.
rxt.'THERCO' = 'LOGIQUE' ; VRAI if implicit coupling of wall/flow thermal
equations
rxt.'vtp' = 'MAILLAGE' ; mesh of the wall.
rxt.'LAMBDA' = 'FLOTTANT' ; thermal conductivity of the wall
(W/m/°C).
rxt.'ROCP' = 'FLOTTANT' ; Rho*Cp of the wall (J/m3/°C).
rxt.'Tp0' = 'FLOTTANT' ; initial temperature of the wall (°C).
rxt.'ECHAN' = 'FLOTTANT' ; heat exchange coefficient fluid / wall
(W/m**2/°C).
VRAI if exchange wall/external
environment.
rxt.'parext' = 'MAILLAGE' ; Mesh of the external surface.
rxt.'HEXT' = 'FLOTTANT' ; heat exchange coefficient with external
environment (W/m**2/°C).
rxt.'TPEXT' = 'FLOTTANT' ; external temperature (°C).
It is possible to define the fields by point for wall thermal properties, for
example to model several material layers.
1) The fields are intialized (by a float) when ENCEINTE is called without
any iteration (graph plotting has to be disabled)
rxt.'GRAPH' = FAUX;
ENCEINTE 0 RXT ;
2) RXT fields (rxt.'TIC'.'LAMBDA' and rxt.'TIC'.'ROCP') are overloaded
* creation of fields on the wanted meshes (here Mg and Md)
* These meshes must be created from wall mesh supports
cvtp='DOMA'RXT.'GEO'.'$vtp''CENTRE'; cWg = 'CONT' Wg;
cWd = 'CONT' Wd;
* In this example Wg and Wd were included in RXT.'vtp' during
the mesh creation
Mg = incl cvtp cWg 'BARY' ;
Md = incl cvtp cWd 'BARY' ;
l_g = 'MANU' 'CHPO' Mg 1 'SCAL' 15.0 'NATURE' 'DISCRET' ;
l_d = 'MANU' 'CHPO' Md 1 'SCAL' 30.0 'NATURE' 'DISCRET' ;
* Overloading of rxt.'TIC'.'LAMBDA'
rxt.'TIC'.'LAMBDA'='KCHT'rxt.'GEO'.'$vtp''SCAL''CENTRE' 15.0 l_d l_g ;
* the same for rxt.'TIC'.'ROCP'
r_g = 'MANU' 'CHPO' Mg 1 'SCAL' (7800.0 '*' 500.0) 'NATURE'
'DISCRET' ;
r_d = 'MANU' 'CHPO' Md 1 'SCAL' (780.0 '*' 500.0) 'NATURE'
'DISCRET' ;
rxt.'TIC'.'ROCP'='KCHT'rxt.'GEO'.'$vtp''SCAL''CENTRE' (7800.0 '*' 500.0) r_d r_g ;
3) The simulation starts with the new wall thermal properties fields.
ENCEINTE NBIT RXT
B/ Prescribed wall temperatures.
--------------------------------
One can prescribe wall temperatures via a heat exchange coefficient.
It allows to modelize a condensor. Three zones are possible.
Example :
rxt.'TIMP1' = table ;
rxt.'TIMP1'.'MAILLAGE' = mesh ;
rxt.'TIMP1'.'t' = prog 0.0 19620. ;
rxt.'TIMP1'.'TIMP' = prog 110.0 110.0 ;
rxt.'TIMP1'.'ECHAN' = 1.e1 ;
.
.
.
.
The value of the heat exchange coefficient is the default value if there is
no condensation o is the lowest value if condensation.
One can also impose a constant wall temperature by using the keyword ECHANP.
rxt.'ECHANP' = table ;
rxt.'ECHANP'.'MAILLAGE' = bidon ;
rxt.'ECHANP'.'TMUR' = 110. ;
rxt.'ECHANP'.'ECHAN' = 1.e1 ;
We can redefine the different characteristics located in the TIC table by
using personal procedur.
C/ Definition of constitutive gases.
------------------------------------
Air is always present
rxt.'VAPEUR' = LOGIQUE ; Presence of steam
rxt.'H2' = LOGIQUE ; Presence of hydrogen
rxt.'HE' = LOGIQUE ; Presence of helium
rxt.'N2' = LOGIQUE ; Presence of N2
rxt.'O2' = LOGIQUE ; Presence of oxygen
rxt.'CO' = LOGIQUE ; Presence of CO
rxt.'CO2' = LOGIQUE ; Presence of CO2
- Initial conditions for fluid volume.
rxt.'TF0' = FLOTTANT ; Initial temperature (in °C).
rxt.'PT0' = FLOTTANT ; Initial total pressure (in Pascal).
rxt.'Yvap0' = FLOTTANT ; Initial steam mass fraction
rxt.MOT= FLOTTANT ; Initial mass fraction for the
incondensable gases (if they are present)
fluid. MOT can take the value 'Yhe0', 'Yh20', 'Yo20',
'Yn20', 'Yco0', 'Yco20'.
* Physical properties of the gazeous mixture
Gaz constants
Rgh2 = 4156.5
Rghe = 2078.25
Rgo2 = 259.8
Rgn2 = 296.9
Rgco2 = 188.9
Rgco = 296.9
Rgvap = 461.513
Rgair = 287.1
muair = 1.800e-5 : dynamic viscosity (air)
alf = 1.800e-5 : thermal diffusivity
lamair= 2.580e-2 : thermal conductivity
db = 1.000e-5 : Brownian diffusivity
Cph2o = 1700.0 : Specific heat at constant pressure for the
steam
Lv = 2.3E6 : Latent heat
The specific heat for all other gases are given by the CALCP procedur.
D/ Turbulence models.
---------------------
If this entry is ommited the flow is considered laminar.
rxt.'MODTURB' = MOT ; Type of turbulence model.
The possibilities are :
a/ rxt.'MODTURB' = 'NUTURB' ; Constant eddy viscosity
rxt.'NUT' = 'FLOTTANT' ; Value of eddy viscosity
b/ rxt.'MODTURB' = 'LMEL' ; Length scale model
rxt.'LMEL' = 'FLOTTANT' ; Value of the length scale.
c/ rxt.'MODTURB' = 'KEPSILON'; (NOT AVAILABLE)
< rxt.'FPAROI' = 'LOGIQUE' ; >
< rxt.'YP' = 'FLOTTANT' ; >
E/ Spray
---------
rxt.'ASPER' = LOGIQUE ; Spray model.
Spray model needs rxt.'VAPEUR' = VRAI ;
rxt.'aspinj' = MAILLAGE ; Mesh of the injection surface for the
dispersed phase.
rxt.'toitf' = MAILLAGE ; Mesh of the upper surface of the
fluid volume
rxt.'rod' = MAILLAGE ; Density of the dispersed phase.
rxt.'Cpd' = MAILLAGE ; Specific heat of the dispersed phase.
rxt.'scenario'.'vzinj' = LISTREEL ; List of injection velocities
(vertical) for the dispersed phase.
rxt.'scenario'.'xdinj' = LISTREEL ; List of volumic fraction of the
dispersed phase at injection.
rxt.'scenario'.'tdinj' = LISTREEL ; List of dispersed phase temperature
at injection.
rxt.'scenario'.'ddinj' = LISTREEL ; List of droplet diameters
at injection.
F/ Mass condensation (NOT AVAILABLE)
--------------------
rxt.'CONDMAS' = LOGIQUE ; Mass condensation model (NOT AVAILABLE)
rxt.'TRAVIS' = LOGIQUE ; TRAVIS model (NOT AVAILABLE)
G/ Scenario definition
----------------------
rxt.'scenario' = TABLE ; Table defining the scenario
- Boundary conditions for the injection and the walls thermally regulated.
The data tables for each injection breach (3 possible breaches) are
rxt.'scenario', rxt.'scenario2' and rxt.'scenario3'.
rxt.'scenario'.'t' = LISTREEL ; List of times (in seconds).
rxt.'scenario'.'qeau' = LISTREEL ; List of mass flow rates for
steam (in Kg/s).
rxt.'scenario'.MOT= LISTREEL ; List of mass flow rates for
the injected incondensables (in Kg/s).
MOT can be equal to 'qair', 'qhe', 'qh2', 'qo2' ,
'qn2', 'qco', 'qco2'.
qair is mandatory, there is always air.
The other flow rates are needed if the corresponding incondensable
is present.
If the user wishes to stop the injection on a breach (every gas component mass
flow rate equal to zero), breach meshes have to be defined again.
rxt.'scenario'.'tinj' = LISTREEL ; List of injection temperatures
in time.
H/ Recombiner definition
------------------------
Recombiners can be defined only if these constituants are present :
H2, N2, O2, VAPEUR
*-- Recombiner
RXT.'RECOMB' = 'TABLE' ;
RXT.'RECOMB' . 1 = 'TABLE' ;
RXT.'RECOMB' . 1 . 'PAREXT' = MAILLAGE ;
RXT.'RECOMB' . 1 . 'ENTREE' = MAILLAGE ;
RXT.'RECOMB' . 1 . 'SORTIE' = MAILLAGE ;
RXT.'RECOMB' . 1 . 'direntr' = POINT ;
RXT.'RECOMB' . 1 . 'dirsort' = POINT ;
We can define N recombiners, it must just create N numeroted tables.
To model a recombiner, several objects must be define :
- PAREXT : Mesh object permitting the description of the outdoor
layer (without the entry and the exit).
- ENTREE : Mesh of the entry of the recombiner
- SORTIE : Mesh of the exit of the recombiner
- direntr : Point defining the direction of the fluid at the
entry of the recombiner
- dirsort : Point defining the direction of the fluid at the
exit of the recombiner
I/ Condensation flow model
--------------------------
rxt.'MODCOND' = MOT: Flow condensation model keyword.
The possibilities are:
a/ rxt.'MODCOND' = 'CHIL0' : Jv = Jstand = kc rho (Yv - Yvsat)
default value.
* Chilton-Colburn model only for very small steam mass fraction.
We use a natural convection correlation.
b/ rxt.'MODCOND' = 'CHIL1' : Jv = Jstand / (1-Yvsat)
(From a volumic mass Fick's law with the steam diffusivity
coefficient in the mixture from Raloc)
III/ Numerical parameters.
--------------------------
rxt.'DT0' = FLOTTANT ; time step.
0 or 1 further informations
rxt.'epsi' = FLOTTANT ; smallest distance for points elimination
(ELIM operator).
rxt.'GRAPH' = LOGIQUE ; display of mean values plots in time.
It is possible to execute a personal procedure at the beginning
of each time step.
rxt.'PRCPERSO'= 'MOT' ; name of the procedure to be executed
rxt.'TABPERSO'= 'TABLE' ; associated table
rxt.'FRPREC'= ENTIER ; frequency for matrix preconditionning
rxt.'DISCR' = FLOTTANT ; Type of spatial discretization.
rxt.'KPRE' = FLOTTANT ; Type of spatial discretization for the
pressure.
rxt.'ALGO' = MOT ; Type of algorithm
'IMPL' semi implicit
'EFM1' semi explicit
indicates wether or not the
matrices are to be droped at the end of the procedure.
indicates that the computation will
reinitialized in order to take into account changes in the model
(new component).
If any entry in the RXT table is added or cancelled rxt.'REINIT'
has to be set to VRAI. If not the computation stops.
indicates wether or not the
energy balance control is used. Default is VRAI.
TO DATE LIMITATIONS OF THE MODELS
* perfect gaz model
* No symetry plane boundary conditions
Guidelines :
I/ Change in the type of boundary conditions
Starting from a previous computation
1/ One get the rxt.'TIC' table
opti rest 'MONFIC.sauv';
rest ;
tic = rxt.'TIC' ;
2/ One get (eventually) the mesh
opti rest 'MONMAIL.sauv';
rest ;
3/ One describe (fully) the new problem
rxt=table ;
rxt.'vtf'= mon maillage ;
rxt. .... etc
4/ One initialyse with the previous tic table
rxt.'TIC'=tic ;
II/ Limiting the size of the 'SAUV' file
See DETMAT entry to drop the MATRIK objects
IV/ Computational results
-------------------------
TABLE 'TIC' Contains calculated unknowns 0D and multi-D
---------------------------------------------------------
Indice Objet
Type Valeur Type Valeur
MOT SOUSTYPE MOT INCO
* Cvm Cpm Gamm : heat capacities of the mixture (J/kg/K)
and ratio
* Roj : density at inlet (kg/m3)
* A/ OD evolutions in time
*-------------------------
MOT Tps FLOTTANT : Physical time
MOT NUPADT ENTIER : time step nummer.
MOT LTPS LISTREEL : list of computed times.
MOT DT FLOTTANT : time step
MOT LMAXU LISTREEL : List in time (LT) of maximum velocity (m/s)
MOT Rhom LISTREEL : LT mean density of the mixture (kg/m3)
MOT Rhomv LISTREEL : LT mean density of steam (kg/m3)
(If VAPEUR VRAI)
MOT Rhomhe LISTREEL : LT helium (kg/m3)
(If THE VRAI)
MOT Rhomh2 LISTREEL : LT h2 (kg/m3)
(If TH2 VRAI)
MOT Rhomo2 LISTREEL : LT o2 (kg/m3)
(If TO2 VRAI)
MOT Rhomn2 LISTREEL : LT n2 (kg/m3)
(If Tn2 VRAI)
MOT Rhomco LISTREEL : LT CO (kg/m3)
(If Tco VRAI)
MOT Rhomco2 LISTREEL : LT CO2 (kg/m3)
(If Tco2 VRAI)
MOT Tfm LISTREEL : LT mean temperature of the mixture (°C)
MOT Tpm LISTREEL : LT mean temperature of the wall (°C)
(If THERMP VRAI)
MOT Ltbp1 LISTREEL : LT prescribed temperature (TTIMP1)
MOT Ltbp2 LISTREEL : LT prescribed temperature (TTIMP2)
MOT Ltbp3 LISTREEL : LT prescribed temperature (TTIMP3)
MOT Qc LISTREEL : LT Total flow rate for condensation (Kg/s)
MOT Qcw LISTREEL : LT condensation flow rate for (THERMP) (Kg/s)
MOT Qc1 LISTREEL : LT condensation flow rate for (TTIMP1) (Kg/s)
MOT Qc2 LISTREEL : LT condensation flow rate for (TTIMP2) (Kg/s)
MOT Qc3 LISTREEL : LT condensation flow rate for (TTIMP3) (Kg/s)
MOT Qc0 LISTREEL : LT condensation flow rate for (ECHANP) (Kg/s)
MOT Econd LISTREEL : LT energy extracted by condensation (J/m3)
MOT Hcond LISTREEL : LT enthalpy extracted by condensation(J/m3)
MOT Econv LISTREEL : LT energy extracted by convection (J/m3)
MOT Easpe LISTREEL : LT energy extracted by spray (J/m3)
(Si ASPER VRAI)
MOT Haspe LISTREEL : LT enthalpy extracted by spray (J/m3)
MOT Qaspe LISTREEL : LT spray flow rate (kg/s)
MOT Remn LISTREEL : LT specific energy of the mixture (J/m3)
MOT Rgpm LISTREEL : LT perfect gaz constant for the mixture (J/kg/K)
MOT Cvm LISTREEL : LT }heat capacities for the mixture (J/kg/K)
MOT Cpm LISTREEL : LT }
MOT Gamm LISTREEL : LT }and ratio
MOT PT LISTREEL : LT thermodynamic pressure
MOT Minj LISTREEL : LT injected mass (Kg)
MOT Mcond LISTREEL : LT condense mass (Kg)
MOT Mrest LISTREEL : LT resident mass (Kg)
MOT guj LISTREEL : LT velocity at inlet (break 1) (m/s)
MOT Qj LISTREEL : LT mass flow rate at inlet (break 1) (Kg/s)
MOT Hj LISTREEL : LT enthalpy at inlet (break 1) (J/m3)
MOT Ej LISTREEL : LT energy at inlet (break 1) (J/m3)
MOT guj2 LISTREEL : LT
MOT Qj2 LISTREEL : LT break 2
MOT Hj2 LISTREEL : LT
MOT Ej2 LISTREEL : LT
MOT TBP1 FLOTTANT : prescribed wall temperature (TTIMP1)
MOT TBP2 FLOTTANT : prescribed wall temperature (TTIMP2)
MOT TBP3 FLOTTANT : prescribed wall temperature (TTIMP3)
MOT TBP0 CHPOINT : prescribed wall temperature (ECHANP)
MOT KHEW FLOTTANT : heat exchange coefficient
wall/fluid THERMP
MOT KHE1 FLOTTANT : heat exchange coefficient TIMP1
MOT KHE2 FLOTTANT : heat exchange coefficient TIMP2
MOT KHE3 FLOTTANT : heat exchange coefficient TIMP3
MOT KHE0 CHPOINT : heat exchange coefficient ECHANP
*--- RECOMBINER ---*
MOT QIN_H2 LISTREEL : total hydrogen mass flow rate at the entry
MOT QIN_H2O LISTREEL : total steam mass flow rate at the entry
MOT QIN_O2 LISTREEL : total oxygen mass flow rate at the entry
MOT QIN_N2 LISTREEL : total nitrogen mass flow rate at the entry
MOT QOUT_H2 LISTREEL : total hydrogen mass flow rate at the exit
MOT QOUT_H2O LISTREEL : total steam mass flow rate at the exit
MOT QOUT_O2 LISTREEL : total oxygen mass flow rate at the exit
MOT QOUT_N2 LISTREEL : total nitrogen mass flow rate at the exit
MOT RECOMB TABLE : Table where different informations
about recombiners are described
RXT.TIC.RECOMB. 1 : Table of the first recombiner
(...)
RXT.TIC.RECOMB. 1 . 'DEB' : Total mass flow rate
RXT.TIC.RECOMB. 1 . 'Uin' : Inlet velocity
RXT.TIC.RECOMB. 1 . 'Uout': Outlet velocity
RXT.TIC.RECOMB. 1 . 'Tin' : Inlet temperature
RXT.TIC.RECOMB. 1 . 'Tout': Outlet temperature
RXT.TIC.RECOMB. 1 . 'Tpla': Temperature of the recombiner plates
RXT.TIC.RECOMB. 1 . 'EFF' : Efficacity of the recombiner
RXT.TIC.RECOMB. 1 . 'Hin' : Inlet enthalpy
RXT.TIC.RECOMB. 1 . 'Hout': Outlet enthalpy
RXT.TIC.RECOMB. 1 . 'R?E' : Density of the ? specie at the inlet
RXT.TIC.RECOMB. 1 . 'R?S' : Density of the ? specie at the outlet
RXT.TIC.RECOMB. 1 . 'Y?E' : Mass fraction of the ? specie at the inlet
RXT.TIC.RECOMB. 1 . 'Y?S' : Mass fraction of the ? specie at the outlet
* B/ multi-D unknowns
*--------------------
MOT UN CHPOINT : Velocity field at current time step
MOT UNM CHPOINT : Velocity field at the previous time step
MOT ROG CHPOINT :
MOT PRES CHPOINT : pressure
MOT TF CHPOINT : temperature field (current time step)
MOT TFNM CHPOINT : temperature field ( previous time step )
MOT RHO CHPOINT : density (current time step)
MOT RHONM CHPOINT : density ( previous time step )
MOT Mu CHPOINT : dynamic viscosity of the mixture
MOT NU CHPOINT : cinematic viscosity of the mixture
MOT NUEFF CHPOINT : effective cinematic viscosity of the mixture
Spray
MOT VN CHPOINT : Velocity field of the disperse phase at the
current time step
MOT TD CHPOINT : Temperature field of the disperse phase
MOT XD CHPOINT : molar fraction of the disperse phase
MOT DD CHPOINT : Droplets diameter
MOT RAIR CHPOINT : density of air (Kg)
MOT RVP CHPOINT : density of steam (Kg)
MOT RHE CHPOINT : density of He (Kg)
MOT RH2 CHPOINT : density of H2 (Kg)
MOT RO2 CHPOINT : density of O2 (Kg)
MOT RN2 CHPOINT : density of N2 (Kg)
MOT RCO2 CHPOINT : density of CO2 (Kg)
MOT RCO CHPOINT : density of CO (Kg)
MOT YVAP FLOTTANT / CHPOINT : Mass fraction (M.F.) of steam
MOT YHE FLOTTANT / CHPOINT :
MOT YH2 FLOTTANT / CHPOINT : FLOTTANT if species missing
MOT YO2 FLOTTANT / CHPOINT :
MOT YN2 FLOTTANT / CHPOINT :
MOT YCO2 FLOTTANT / CHPOINT :
MOT YCO FLOTTANT / CHPOINT :
MOT YAIR FLOTTANT / CHPOINT :
GEO TABLE contains geometrical informations, in particular
the different MMODEL objects.
Entries Objects
Type Valeur Type Commentaires
MOT epsi FLOTTANT : minimum distance between two points
see ELIM operator
MOT $vtf MMODEL :
MOT $menvf MMODEL :
MOT $axe MMODEL : axe or symetry plane
MOT $vtp MMODEL : wall thermics
MOT $mtp1 MMODEL : prescribed wall temperature (TIMP1)
MOT $mtp2 MMODEL : prescribed wall temperature (TIMP2)
MOT $mtp3 MMODEL : prescribed wall temperature (TIMP3)
MOT $mtp0 MMODEL : prescribed wall temperature (ECHANP)
MOT Pimp MAILLAGE : mesh of type POI1 containing the point
where the pressure is imposed.