CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

why my momentum and mass not convergence

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By ghorrocks

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 17, 2012, 22:43
Default why my momentum and mass not convergence
  #1
New Member
 
Xing Wu
Join Date: Sep 2010
Posts: 7
Rep Power: 15
wwwuxing is on a distinguished road


dear all,



my case is simulate the the fan in an tools, i just want to know the massflow, but i can not get the right result ,since the RMS not convergence even more than 1000 iterations.



the parameters is copied below,




LIBRARY:
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:
。。。。。。。。。。。。。。
END
END
END
FLOW: Flow Analysis 1
SOLUTION UNITS:
Angle Units = [rad]
Length Units = [m]
Mass Units = [g]
Solid Angle Units = [sr]
Temperature Units = [K]
Time Units = [s]
END
ANALYSIS TYPE:
Option = Steady State
EXTERNAL SOLVER COUPLING:
Option = None
END
END
DOMAIN: housing
Coord Frame = Coord 0
Domain Type = Fluid
Location = DOMAIN_OF_STATOR
BOUNDARY: Default Fluid Fluid Interface Side 1
Boundary Type = INTERFACE
Location = Primitive 2D AS,Primitive 2D AT,Primitive 2D AU,Primitive \
2D AV,Primitive 2D R,Primitive 2D S,Primitive 2D T,Primitive 2D U
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = Conservative Interface Flux
END
TURBULENCE:
Option = Conservative Interface Flux
END
END
END
BOUNDARY: baffle
Boundary Type = WALL
Location = BAFFLE
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = No Slip Wall
END
WALL ROUGHNESS:
Option = Smooth Wall
END
END
END
BOUNDARY: brakets
Boundary Type = WALL
Location = BRACKETS
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = No Slip Wall
END
WALL ROUGHNESS:
Option = Smooth Wall
END
END
END
BOUNDARY: housing Default
Boundary Type = WALL
Location = HEAT_SINK,MOSFET1,MOSFET2,PCB
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = No Slip Wall
END
WALL ROUGHNESS:
Option = Smooth Wall
END
END
END
。。。。。。。。。。。。。。
BOUNDARY: inlet
Boundary Type = OPENING
Location = INLET,INLET2
BOUNDARY CONDITIONS:
FLOW DIRECTION:
Option = Normal to Boundary Condition
END
FLOW REGIME:
Option = Subsonic
END
MASS AND MOMENTUM:
Option = Opening Pressure and Direction
Relative Pressure = 0 [Pa]
END
TURBULENCE:
Option = Medium Intensity and Eddy Viscosity Ratio
END
END
END
。。。。。。。。。。。。。
BOUNDARY: outlet
Boundary Type = OUTLET
Location = OPENING
BOUNDARY CONDITIONS:
FLOW REGIME:
Option = Subsonic
END
MASS AND MOMENTUM:
Option = Average Static Pressure
Pressure Profile Blend = 0.05
Relative Pressure = 0 [Pa]
END
。。。。。。。。。。。。。
DOMAIN: rotor domain
Coord Frame = Coord 0
Domain Type = Fluid
Location = DOMAIN_OF_ROTOR
BOUNDARY: Default Fluid Fluid Interface Side 2
Boundary Type = INTERFACE
Location = Primitive 2D AO,Primitive 2D AP,Primitive 2D AQ,Primitive \
2D AR,Primitive 2D AW,Primitive 2D AX,Primitive 2D AY,Primitive 2D AZ
BOUNDARY CONDITIONS:
MASS AND MOMENTUM:
Option = Conservative Interface Flux
END
TURBULENCE:
Option = Conservative Interface Flux
END
END
END
END
CONVERGENCE CONTROL:
Maximum Number of Iterations = 500
Minimum Number of Iterations = 1
Physical Timescale = 0.01 [s]
Timescale Control = Physical Timescale
END
CONVERGENCE CRITERIA:
Residual Target = 0.00001
Residual Type = RMS
END
DYNAMIC MODEL CONTROL:
Global Dynamic Model Control = On
END
END
END
。。。。。。。。。。。。
Memory Allocation Factor = 1.0
END
END
。。。。。。。。。。。。
Attached Images
File Type: jpg momentum and mass.jpg (31.1 KB, 58 views)
wwwuxing is offline   Reply With Quote

Old   May 17, 2012, 22:52
Default the fluid domain
  #2
New Member
 
Xing Wu
Join Date: Sep 2010
Posts: 7
Rep Power: 15
wwwuxing is on a distinguished road
the fluid domain
Attached Images
File Type: jpg 5-18-2012 10-49-20 AM.jpg (26.4 KB, 51 views)
wwwuxing is offline   Reply With Quote

Old   May 18, 2012, 02:01
Default
  #3
New Member
 
Sainath
Join Date: Mar 2012
Posts: 27
Rep Power: 14
sainath.s@tdps.co.in is on a distinguished road
Is that a Generator you are trying to model?..
sainath.s@tdps.co.in is offline   Reply With Quote

Old   May 18, 2012, 07:49
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
This question is covered by an FAQ:

http://www.cfd-online.com/Wiki/Ansys...gence_criteria
Goenitz likes this.
ghorrocks is offline   Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
mass flow in is not equal to mass flow out saii CFX 12 March 19, 2018 05:21
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
Derivation of Momentum Equation in Integral Form Demonwolf Main CFD Forum 2 October 29, 2009 19:53
Mass source, Momentum source theory. diffo FLUENT 4 August 21, 2009 10:26
Problem with Mass source, Momentum source theory diffo Fluent UDF and Scheme Programming 0 August 20, 2009 06:10


All times are GMT -4. The time now is 15:37.