
[Sponsors] 
Domain Reference Pressure and mass flow inlet boundary 

LinkBack  Thread Tools  Search this Thread  Display Modes 
January 19, 2010, 20:29 
Domain Reference Pressure and mass flow inlet boundary

#1 
Member

hello everyone, im very stuck with the settings of my boundary condition and specially with the referente pressure:
im modelling combustion with flamelet, and i want to use mass flow for all the inlet (air and fuel), the air enters to the chamber with 6.4bar and the fuel with 14.31bar, my question is: how can i set the mass flow boundary for a specific pressure? when i set this boundary, i just set the temperature, but the density depends on pressure and temperature, how can i set this two different mass flow? another thing its, the domain reference pressure affect to the whole domain, so, if a set the boundary of fuel (mass flow) this mas flow will be affected for this pressure, so im not sure to what refference pressure set.(i was using the pressure of the inlet air, becuase in a chamber its relleativy constant). well, please helpe im vvvvvvvvvery stuck with this thanks ver much 

January 20, 2010, 17:07 

#2 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 16,545
Rep Power: 128 
If you know both the mass flow rates and pressures of the input gases then I would use a mass flow rate boundary for the inlets and a pressure boundary at the outlet (I assume you know the exit pressure  it is probably just atmospheric pressure with a small allowance for exhaust pipe losses). Then you can check the input gas pressure as a check of the accuracy of your simulation.
The reference pressure is purely a numerical thing. You set the reference pressure so the numerical accuracy of the pressure field is higher as the solver works on the pressure relative to the reference pressure. Set the reference pressure to be the outlet pressure (if you are using a pressure outlet) or the average pressure in the chamber. The exact value you use is not really important, but you do need to make sure all pressures you specify are correct relative to the reference pressure. 

January 20, 2010, 23:15 

#3 
Member

Thanks very much for your time:
First: im trying to use inlets mass flow boundary because i read in some pdf, that's is a better choice for compressible flows instead of velocity im a right?. second: in a firts time i was using the tutorial of combustion, for the setting of the reference pressure (1atm) and pressure boundary outlet (0Pa). but this is correct? 0Pa to the outlet its a very very low pressure?, in my case i dont have any information of the pressure outelet, so im using this configuration: 6.40(bar)>reference pressure (this value its the pressure of the inlet of air) 6(bar)> to the oulet boundary condition (because in a combustion chamber of a turbine, generally the losses are of arround a 6%). but im not sure if this its right?, in this moment, i just want to make an a firts aproximation of this simulation, and im wondering who value is the better choice, the values of the tutorial (for reference 1atm and outlet pressure 0Pa),or mines =/. another things its, when i run the simulation with velocitys, the flow field(temperature,radiation) are not homogeneous, and all the boundary has the same value, like this image (when i try with randoms values of mass flow rate boundary, this not happend)the first image its the good one =) ) sorry for all the inappropriate question but im working by myself in CFD, and i dont have anyone to ask about the settings of the software =/. thanks very much for your time best regards Mauricio 

January 21, 2010, 01:15 

#4  
Member

Quote:
ohh and i forgot,my values of mas flow rate are in the ISO CONDITION (15ºc and 1atm)(from the documentation of the turbine), but in the operation of the turbine i have other values for temp and pressure, what can i do? 

January 21, 2010, 17:42 

#5 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 16,545
Rep Power: 128 
You cannot set both the flow rate and pressure at the same boundary. It is a numerical impossibility. Do some reading on "well posed boundary conditions" for CFD simulations.
It should be a trivial matter for you to convert the flow rates at ISO conditions to any other temperature and pressure. If you can't do this then why are you doing CFD? .......and anyway, if you know the mass flow rate it does not matter what temperature and pressure you are at! 

January 21, 2010, 19:57 

#6 
Member

you have rigth,
im gona check if this boundary conditions are correct. thanks 

January 22, 2010, 04:00 

#7 
Senior Member
Attesz
Join Date: Mar 2009
Location: Munich
Posts: 367
Rep Power: 13 
if you know the inlet mass flow rate and pressure value, you are lucky, because if you set the mass flow after the simulation you can check the pressure at the inlet, and you can validate! setting both value means an overconstrainted boundary contition, where you set two quantities wich depend on each other.


January 23, 2010, 02:07 

#9 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 16,545
Rep Power: 128 
As I said, it looks like you need to do some reading into well posed boundary conditions. Some combinations of boundary conditions are not possible and will never converge. Mass flow rate inlet and mass flow rate outlet on a steady state simulation is an example of an impossible boundary condition. The documentation has some basic information about this, I think under choice of boundary conditions.


January 23, 2010, 02:54 

#10 
Member

yeah, you have all right, in the documentation said:
best robustness: mass flow rate or velocity (inlet) and for oultetressure im using for the outlet static average pressure. but its true that for compressible flows (combustion case) its better use mass flow rate for inlet boundary instead velocity?. thanks 

January 23, 2010, 05:12 

#11 
Senior Member
Attesz
Join Date: Mar 2009
Location: Munich
Posts: 367
Rep Power: 13 
mass flow rate or velocity inlet are good, static pressure outlet also. i recommend not to use averaging, because the solver use that value for the whole area, and can give bad results.
i dont know, how disturbed is the flow at inlet and at the outlet. if the inlet flow is consistent, and the outlet not, maybe inlet total pressure and outlet mass flow is better, because the pressure at outlet is very uneven. you must set boundary conditions taking into account the real phenomenons... 

January 23, 2010, 06:00 

#12 
Member

thanks very much for your reply
yeah one of my difficults its the exact value for the inlet or outlet boundary, because this turbine(hitachi ge frame V 1974) its very old and dont have measure instrument in the places that i need ( mass flow of air, temperature of combustor) so im using aproximation based on tables parameter of the turbine. it was very helpful, im gonna use your advice for the outlet pressure, im gona use just static pressure and not the average static pressure. thanks very much 

February 11, 2010, 21:28 

#13 
Member

ghorrocks; sorry for that stupid question about the mass flow rate boundary! i really dont know what i was thinking. my simulation finally walk well. when i use 0bar for reference pressure and some static pressure for the outlet everything works fine, and the results inlete velocity correct.
thanks very much again, and sorry for that stupid question , the first think that imgona do finishing this work, its sleep long time! best regards 

March 1, 2017, 14:51 

#14  
Member
Ftab
Join Date: Sep 2011
Posts: 87
Rep Power: 11 
Quote:
Could you please explain why do you say that? I am confused. If you have a pipe which branches into two. I set a mass flow inlet and then put say 30% of mass flow outlet in one branch and 70% in another. For incompressible steady simulation, why is this wrong? 

March 1, 2017, 17:53 

#15 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 16,545
Rep Power: 128 
It cannot work because there is nothing to define the pressure.


March 6, 2017, 17:20 

#16  
Member
Ftab
Join Date: Sep 2011
Posts: 87
Rep Power: 11 
Quote:
I still agree that theoretically only one node pressure value is sufficient to solve all mass flow BC case. 

March 6, 2017, 18:10 

#17 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 16,545
Rep Power: 128 
You are correct. It does mean the absolute value of the pressure is arbitrary. So I move onto the second problem....
If you define the mass flow rate in and out of a domain in a steady state simulation, then it is not possible to achieve imbalances convergence. All floating point numbers are approximate in a computer, meaning that after floating point approximation your inlet flow will not balance your outlet flow. This small imbalance in flow rates cannot be removed as there is nothing the solver can adjust to balance it. This means you cannot converge the imbalances in this approach. This imbalance may be small or large depending on your simulation setup. More completely: Your simulation is not well posed. Wikipedia's definition of well posed (https://en.wikipedia.org/wiki/Wellposed_problem) states that the solution has to be unique. Your condition with the boundary conditions only is not unique as the pressure level is not set, and therefore is badly posed. You have to make an additional assumption of the pressure at a point to make it solvable. Here is another reference which dives into more mathematical rigour on the definition of well posed: http://liu.divaportal.org/smash/get...FULLTEXT01.pdf 

July 31, 2018, 10:16 

#18 
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 16 
Hi Glenn,
does the Total Pressure at Inlet in a domain with No Outlet is a wellposed problem or illposed problem? Can I study the pressure drops in the system with Total Pressure at Inlet. It's a high pressure hydraulic system where hydraulic oil enters from one inlet. Pressure and Mass flow rate are known at Inlet. The pipes diameters are of the order of milimeters and even at some places microns. Pressure at Inlet is about 100 bars. I cannot made the simulation to run as it is very unstable. I tried many things like refining the mesh, decreasing the physical time step very very low (like 10e20), used ramping function to ramp the pressure at Inlet and even i extented the inlet 10 times upstream to allow the flow to develop but unfortunately Nothing helped. I am not sure if the domain with No Outlet is an unusual problem for CFX to solve OR the system of the orders of millimeters with very high pressure is a difficult for CFX to solve OR using Total pressure boundary condition at Inlet without any Outlet in the domain is a problem for CFX? Any suggestions are welcomed. Thanks in advance. Regards 

July 31, 2018, 19:39 

#19 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 16,545
Rep Power: 128 
To answer that question I would have to see what you are modelling and how you are modelling it. Please attach some images which show what boundary conditions you apply and your CCL.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum. 

August 1, 2018, 04:36 

#20 
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 16 
Hello Glenn,
thanks for your reply. I have attached the image with the message. As mentioned previously the purpose of the simulation is to study the pressure drops in the system. CCL: LIBRARY: CEL: EXPRESSIONS: Flow000 = 0 [bar] Flow999 = 109 [bar] Iter = 4000 flowapplied = Flow000 + \ Flow999*aitern/Iter*step(Iteraitern)+Flow999*step(aiternIter) END END MATERIAL GROUP: Air Data Group Description = Ideal gas and constant property air. Constant \ properties are for dry air at STP (0 C, 1 atm) and 25 C, 1 atm. END MATERIAL GROUP: CHT Solids Group Description = Pure solid substances that can be used for conjugate \ heat transfer. END MATERIAL GROUP: Calorically Perfect Ideal Gases Group Description = Ideal gases with constant specific heat capacity. \ Specific heat is evaluated at STP. END MATERIAL GROUP: Constant Property Gases Group Description = Gaseous substances with constant properties. \ Properties are calculated at STP (0C and 1 atm). Can be combined with \ NASA SP273 materials for combustion modelling. END MATERIAL GROUP: Constant Property Liquids Group Description = Liquid substances with constant properties. END MATERIAL GROUP: Dry Peng Robinson Group Description = Materials with properties specified using the built \ in Peng Robinson equation of state. Suitable for dry real gas modelling. END MATERIAL GROUP: Dry Redlich Kwong Group Description = Materials with properties specified using the built \ in Redlich Kwong equation of state. Suitable for dry real gas modelling. END MATERIAL GROUP: Dry Soave Redlich Kwong Group Description = Materials with properties specified using the built \ in Soave Redlich Kwong equation of state. Suitable for dry real gas \ modelling. END MATERIAL GROUP: Dry Steam Group Description = Materials with properties specified using the IAPWS \ equation of state. Suitable for dry steam modelling. END MATERIAL GROUP: Gas Phase Combustion Group Description = Ideal gas materials which can be use for gas phase \ combustion. Ideal gas specific heat coefficients are specified using \ the NASA SP273 format. END MATERIAL GROUP: IAPWS IF97 Group Description = Liquid, vapour and binary mixture materials which use \ the IAPWS IF97 equation of state. Materials are suitable for \ compressible liquids, phase change calculations and dry steam flows. END MATERIAL GROUP: Interphase Mass Transfer Group Description = Materials with reference properties suitable for \ performing either Eulerian or Lagrangian multiphase mass transfer \ problems. Examples include cavitation, evaporation or condensation. END MATERIAL GROUP: Liquid Phase Combustion Group Description = Liquid and homogenous binary mixture materials which \ can be included with Gas Phase Combustion materials if combustion \ modelling also requires phase change (eg: evaporation) for certain \ components. END MATERIAL GROUP: Particle Solids Group Description = Pure solid substances that can be used for particle \ tracking END MATERIAL GROUP: Peng Robinson Dry Hydrocarbons Group Description = Common hydrocarbons which use the Peng Robinson \ equation of state. Suitable for dry real gas models. END MATERIAL GROUP: Peng Robinson Dry Refrigerants Group Description = Common refrigerants which use the Peng Robinson \ equation of state. Suitable for dry real gas models. END MATERIAL GROUP: Peng Robinson Dry Steam Group Description = Water materials which use the Peng Robinson equation \ of state. Suitable for dry steam modelling. END MATERIAL GROUP: Peng Robinson Wet Hydrocarbons Group Description = Common hydrocarbons which use the Peng Robinson \ equation of state. Suitable for condensing real gas models. END MATERIAL GROUP: Peng Robinson Wet Refrigerants Group Description = Common refrigerants which use the Peng Robinson \ equation of state. Suitable for condensing real gas models. END MATERIAL GROUP: Peng Robinson Wet Steam Group Description = Water materials which use the Peng Robinson equation \ of state. Suitable for condensing steam modelling. END MATERIAL GROUP: Real Gas Combustion Group Description = Real gas materials which can be use for gas phase \ combustion. Ideal gas specific heat coefficients are specified using \ the NASA SP273 format. END MATERIAL GROUP: Redlich Kwong Dry Hydrocarbons Group Description = Common hydrocarbons which use the Redlich Kwong \ equation of state. Suitable for dry real gas models. END MATERIAL GROUP: Redlich Kwong Dry Refrigerants Group Description = Common refrigerants which use the Redlich Kwong \ equation of state. Suitable for dry real gas models. END MATERIAL GROUP: Redlich Kwong Dry Steam Group Description = Water materials which use the Redlich Kwong equation \ of state. Suitable for dry steam modelling. END MATERIAL GROUP: Redlich Kwong Wet Hydrocarbons Group Description = Common hydrocarbons which use the Redlich Kwong \ equation of state. Suitable for condensing real gas models. END MATERIAL GROUP: Redlich Kwong Wet Refrigerants Group Description = Common refrigerants which use the Redlich Kwong \ equation of state. Suitable for condensing real gas models. END MATERIAL GROUP: Redlich Kwong Wet Steam Group Description = Water materials which use the Redlich Kwong equation \ of state. Suitable for condensing steam modelling. END MATERIAL GROUP: Soave Redlich Kwong Dry Hydrocarbons Group Description = Common hydrocarbons which use the Soave Redlich Kwong \ equation of state. Suitable for dry real gas models. END MATERIAL GROUP: Soave Redlich Kwong Dry Refrigerants Group Description = Common refrigerants which use the Soave Redlich Kwong \ equation of state. Suitable for dry real gas models. END MATERIAL GROUP: Soave Redlich Kwong Dry Steam Group Description = Water materials which use the Soave Redlich Kwong \ equation of state. Suitable for dry steam modelling. END MATERIAL GROUP: Soave Redlich Kwong Wet Hydrocarbons Group Description = Common hydrocarbons which use the Soave Redlich Kwong \ equation of state. Suitable for condensing real gas models. END MATERIAL GROUP: Soave Redlich Kwong Wet Refrigerants Group Description = Common refrigerants which use the Soave Redlich Kwong \ equation of state. Suitable for condensing real gas models. END MATERIAL GROUP: Soave Redlich Kwong Wet Steam Group Description = Water materials which use the Soave Redlich Kwong \ equation of state. Suitable for condensing steam modelling. END MATERIAL GROUP: Soot Group Description = Solid substances that can be used when performing \ soot modelling END MATERIAL GROUP: User Group Description = Materials that are defined by the user END MATERIAL GROUP: Water Data Group Description = Liquid and vapour water materials with constant \ properties. Can be combined with NASA SP273 materials for combustion \ modelling. END MATERIAL GROUP: Wet Peng Robinson Group Description = Materials with properties specified using the built \ in Peng Robinson equation of state. Suitable for wet real gas modelling. END MATERIAL GROUP: Wet Redlich Kwong Group Description = Materials with properties specified using the built \ in Redlich Kwong equation of state. Suitable for wet real gas modelling. END MATERIAL GROUP: Wet Soave Redlich Kwong Group Description = Materials with properties specified using the built \ in Soave Redlich Kwong equation of state. Suitable for wet real gas \ modelling. END MATERIAL GROUP: Wet Steam Group Description = Materials with properties specified using the IAPWS \ equation of state. Suitable for wet steam modelling. END MATERIAL: Air Ideal Gas Material Description = Air Ideal Gas (constant Cp) Material Group = Air Data, Calorically Perfect Ideal Gases Option = Pure Substance Thermodynamic State = Gas PROPERTIES: Option = General Material EQUATION OF STATE: Molar Mass = 28.96 [kg kmol^1] Option = Ideal Gas END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 1.0044E+03 [J kg^1 K^1] Specific Heat Type = Constant Pressure END REFERENCE STATE: Option = Specified Point Reference Pressure = 1 [atm] Reference Specific Enthalpy = 0. [J/kg] Reference Specific Entropy = 0. [J/kg/K] Reference Temperature = 25 [C] END DYNAMIC VISCOSITY: Dynamic Viscosity = 1.831E05 [kg m^1 s^1] Option = Value END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 2.61E2 [W m^1 K^1] END ABSORPTION COEFFICIENT: Absorption Coefficient = 0.01 [m^1] Option = Value END SCATTERING COEFFICIENT: Option = Value Scattering Coefficient = 0.0 [m^1] END REFRACTIVE INDEX: Option = Value Refractive Index = 1.0 [m m^1] END END END MATERIAL: Air at 25 C Material Description = Air at 25 C and 1 atm (dry) Material Group = Air Data, Constant Property Gases Option = Pure Substance Thermodynamic State = Gas PROPERTIES: Option = General Material EQUATION OF STATE: Density = 1.185 [kg m^3] Molar Mass = 28.96 [kg kmol^1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 1.0044E+03 [J kg^1 K^1] Specific Heat Type = Constant Pressure END REFERENCE STATE: Option = Specified Point Reference Pressure = 1 [atm] Reference Specific Enthalpy = 0. [J/kg] Reference Specific Entropy = 0. [J/kg/K] Reference Temperature = 25 [C] END DYNAMIC VISCOSITY: Dynamic Viscosity = 1.831E05 [kg m^1 s^1] Option = Value END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 2.61E02 [W m^1 K^1] END ABSORPTION COEFFICIENT: Absorption Coefficient = 0.01 [m^1] Option = Value END SCATTERING COEFFICIENT: Option = Value Scattering Coefficient = 0.0 [m^1] END REFRACTIVE INDEX: Option = Value Refractive Index = 1.0 [m m^1] END THERMAL EXPANSIVITY: Option = Value Thermal Expansivity = 0.003356 [K^1] END END END MATERIAL: Aluminium Material Group = CHT Solids, Particle Solids Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 2702 [kg m^3] Molar Mass = 26.98 [kg kmol^1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 9.03E+02 [J kg^1 K^1] END REFERENCE STATE: Option = Specified Point Reference Specific Enthalpy = 0 [J/kg] Reference Specific Entropy = 0 [J/kg/K] Reference Temperature = 25 [C] END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 237 [W m^1 K^1] END END END MATERIAL: Copper Material Group = CHT Solids, Particle Solids Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 8933 [kg m^3] Molar Mass = 63.55 [kg kmol^1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 3.85E+02 [J kg^1 K^1] END REFERENCE STATE: Option = Specified Point Reference Specific Enthalpy = 0 [J/kg] Reference Specific Entropy = 0 [J/kg/K] Reference Temperature = 25 [C] END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 401.0 [W m^1 K^1] END END END MATERIAL: Oil Material Group = User Option = Pure Substance Thermodynamic State = Liquid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 881 [kg m^3] Molar Mass = 1.0 [kg kmol^1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 1861 [J kg^1 K^1] Specific Heat Type = Constant Pressure END DYNAMIC VISCOSITY: Dynamic Viscosity = 0.029073 [kg m^1 s^1] Option = Value END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 0.14 [W m^1 K^1] END END END MATERIAL: Soot Material Group = Soot Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 2000 [kg m^3] Molar Mass = 12 [kg kmol^1] Option = Value END REFERENCE STATE: Option = Automatic END ABSORPTION COEFFICIENT: Absorption Coefficient = 0 [m^1] Option = Value END END END MATERIAL: Steel Material Group = CHT Solids, Particle Solids Option = Pure Substance Thermodynamic State = Solid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 7854 [kg m^3] Molar Mass = 55.85 [kg kmol^1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 4.34E+02 [J kg^1 K^1] END REFERENCE STATE: Option = Specified Point Reference Specific Enthalpy = 0 [J/kg] Reference Specific Entropy = 0 [J/kg/K] Reference Temperature = 25 [C] END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 60.5 [W m^1 K^1] END END END MATERIAL: Water Material Description = Water (liquid) Material Group = Water Data, Constant Property Liquids Option = Pure Substance Thermodynamic State = Liquid PROPERTIES: Option = General Material EQUATION OF STATE: Density = 997.0 [kg m^3] Molar Mass = 18.02 [kg kmol^1] Option = Value END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 4181.7 [J kg^1 K^1] Specific Heat Type = Constant Pressure END REFERENCE STATE: Option = Specified Point Reference Pressure = 1 [atm] Reference Specific Enthalpy = 0.0 [J/kg] Reference Specific Entropy = 0.0 [J/kg/K] Reference Temperature = 25 [C] END DYNAMIC VISCOSITY: Dynamic Viscosity = 8.899E4 [kg m^1 s^1] Option = Value END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 0.6069 [W m^1 K^1] END ABSORPTION COEFFICIENT: Absorption Coefficient = 1.0 [m^1] Option = Value END SCATTERING COEFFICIENT: Option = Value Scattering Coefficient = 0.0 [m^1] END REFRACTIVE INDEX: Option = Value Refractive Index = 1.0 [m m^1] END THERMAL EXPANSIVITY: Option = Value Thermal Expansivity = 2.57E04 [K^1] END END END MATERIAL: Water Ideal Gas Material Description = Water Vapour Ideal Gas (100 C and 1 atm) Material Group = Calorically Perfect Ideal Gases, Water Data Option = Pure Substance Thermodynamic State = Gas PROPERTIES: Option = General Material EQUATION OF STATE: Molar Mass = 18.02 [kg kmol^1] Option = Ideal Gas END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 2080.1 [J kg^1 K^1] Specific Heat Type = Constant Pressure END REFERENCE STATE: Option = Specified Point Reference Pressure = 1.014 [bar] Reference Specific Enthalpy = 0. [J/kg] Reference Specific Entropy = 0. [J/kg/K] Reference Temperature = 100 [C] END DYNAMIC VISCOSITY: Dynamic Viscosity = 9.4E06 [kg m^1 s^1] Option = Value END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 193E04 [W m^1 K^1] END ABSORPTION COEFFICIENT: Absorption Coefficient = 1.0 [m^1] Option = Value END SCATTERING COEFFICIENT: Option = Value Scattering Coefficient = 0.0 [m^1] END REFRACTIVE INDEX: Option = Value Refractive Index = 1.0 [m m^1] END END END END FLOW: Flow Analysis 1 SOLUTION UNITS: Angle Units = [rad] Length Units = [m] Mass Units = [kg] Solid Angle Units = [sr] Temperature Units = [K] Time Units = [s] END ANALYSIS TYPE: Option = Steady State EXTERNAL SOLVER COUPLING: Option = None END END DOMAIN: Default Domain Coord Frame = Coord 0 Domain Type = Fluid Location = FLUID BOUNDARY: Inlet Boundary Type = INLET Location = INLET BOUNDARY CONDITIONS: FLOW DIRECTION: Option = Normal to Boundary Condition END FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Option = Total Pressure Relative Pressure = flowapplied END TURBULENCE: Option = Medium Intensity and Eddy Viscosity Ratio END END END BOUNDARY: Symmetry Boundary Type = SYMMETRY Location = Primitive 2D A,Primitive 2D B END BOUNDARY: Walls Boundary Type = WALL Location = GEOM_1 GEOM_OBERFL_CHE_1 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall END WALL ROUGHNESS: Option = Smooth Wall END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Option = None END REFERENCE PRESSURE: Reference Pressure = 1 [bar] END END FLUID DEFINITION: Fluid 1 Material = Oil Option = Material Library MORPHOLOGY: Option = Continuous Fluid END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Fluid Temperature = 25 [C] Option = Isothermal END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = SST END TURBULENT WALL FUNCTIONS: Option = Automatic END END END OUTPUT CONTROL: BACKUP DATA RETENTION: Option = Delete Old Files END BACKUP RESULTS: Backup Results 1 File Compression Level = Default Option = Standard OUTPUT FREQUENCY: Iteration Interval = 100 Option = Iteration Interval END END RESULTS: File Compression Level = Default Option = Standard END END SOLVER CONTROL: Turbulence Numerics = High Resolution ADVECTION SCHEME: Option = High Resolution END CONVERGENCE CONTROL: Maximum Number of Iterations = 8000 Minimum Number of Iterations = 1 Physical Timescale = 1e20 [s] Timescale Control = Physical Timescale END CONVERGENCE CRITERIA: Residual Target = 1e010 Residual Type = MAX END DYNAMIC MODEL CONTROL: Global Dynamic Model Control = On END END END COMMAND FILE: Version = 19.1 END 

Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Wind turbine simulation  Saturn  CFX  58  July 3, 2020 02:13 
mass flow in is not equal to mass flow out  saii  CFX  12  March 19, 2018 06:21 
RPM in Wind Turbine  Pankaj  CFX  9  November 23, 2009 05:05 
Convective Heat Transfer  Heat Exchanger  Mark  CFX  6  November 15, 2004 16:55 
New topic on same subject  Flow around race car  Tudor Miron  CFX  15  April 2, 2004 07:18 