[kmgraju]

Dear friends

I am trying to simulate a mixture of gas and soot particles .
My idea is to trap the soot particle by suitable design of the chamber.
Please find the CCL and attached geometry . I could not find any particle movement and no sticking effect in cfx post .
Kindly rectify my mistake

Your kind help is highly appreciated

Thank you

kmgraju


LIBRARY:

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 = 1.831E-05 [kg m^-1 s^-1]

Option = Value

END

THERMAL CONDUCTIVITY:

Option = Value

Thermal Conductivity = 2.61E-2 [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: 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

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 = B40

BOUNDARY: Boundary 1

Boundary Type = INLET

Location = F54.40

BOUNDARY CONDITIONS:

FLOW REGIME:

Option = Subsonic

END

MASS AND MOMENTUM:

Normal Speed = 10 [m s^-1]

Option = Normal Speed

END

TURBULENCE:

Option = Medium Intensity and Eddy Viscosity Ratio

END

END

FLUID: soot

BOUNDARY CONDITIONS:

MASS AND MOMENTUM:

Normal Speed = 10 [m s^-1]

Option = Normal Speed

END

PARTICLE MASS FLOW RATE:

Mass Flow Rate = 0.8 [kg s^-1]

END

PARTICLE POSITION:

Option = Uniform Injection

NUMBER OF POSITIONS:

Number = 2000

Option = Direct Specification

END

END

END

END

END

BOUNDARY: out

Boundary Type = OUTLET

Location = F48.40

BOUNDARY CONDITIONS:

FLOW REGIME:

Option = Subsonic

END

MASS AND MOMENTUM:

Option = Average Static Pressure

Pressure Profile Blend = 0.05

Relative Pressure = 0 [Pa]

END

PRESSURE AVERAGING:

Option = Average Over Whole Outlet

END

END

END

BOUNDARY: wall

Boundary Type = WALL

Location = \

F41.40,F42.40,F43.40,F44.40,F45.40,F46.40,F47.40,F 49.40,F50.40,F51.40\

,F52.40,F53.40

BOUNDARY CONDITIONS:

MASS AND MOMENTUM:

Option = No Slip Wall

END

WALL ROUGHNESS:

Option = Rough Wall

Sand Grain Roughness Height = 0.2 [mm]

END

END

FLUID: soot

BOUNDARY CONDITIONS:

PARTICLE WALL INTERACTION:

Option = Equation Dependent

END

VELOCITY:

Option = Restitution Coefficient

Parallel Coefficient of Restitution = 1.0

Perpendicular Coefficient of Restitution = 0.3131

END

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 [atm]

END

END

FLUID DEFINITION: Air

Material = Air Ideal Gas

Option = Material Library

MORPHOLOGY:

Option = Continuous Fluid

END

END

FLUID DEFINITION: soot

Material = Soot

Option = Material Library

MORPHOLOGY:

Option = Dispersed Particle Transport Solid

PARTICLE DIAMETER CHANGE:

Option = Mass Equivalent

END

PARTICLE DIAMETER DISTRIBUTION:

Diameter = 1e-10 [m]

Option = Specified Diameter

END

PARTICLE SHAPE FACTORS:

Cross Sectional Area Factor = 1.0

END

END

END

FLUID MODELS:

COMBUSTION MODEL:

Option = None

END

FLUID: soot

EROSION MODEL:

Option = None

END

PARTICLE ROUGH WALL MODEL:

Option = None

END

END

HEAT TRANSFER MODEL:

Fluid Temperature = 300 [C]

Option = Isothermal

END

THERMAL RADIATION MODEL:

Option = None

END

TURBULENCE MODEL:

Option = k epsilon

END

TURBULENT WALL FUNCTIONS:

Option = Scalable

END

END

FLUID PAIR: Air | soot

Particle Coupling = One-way Coupling

MOMENTUM TRANSFER:

DRAG FORCE:

Option = Schiller Naumann

END

PRESSURE GRADIENT FORCE:

Option = None

END

TURBULENT DISPERSION FORCE:

Option = None

END

VIRTUAL MASS FORCE:

Option = None

END

END

END

END

INITIALISATION:

Option = Automatic

INITIAL CONDITIONS:

Velocity Type = Cartesian

CARTESIAN VELOCITY COMPONENTS:

Option = Automatic

END

STATIC PRESSURE:

Option = Automatic

END

TURBULENCE INITIAL CONDITIONS:

Option = Medium Intensity and Eddy Viscosity Ratio

END

END

END

OUTPUT CONTROL:

RESULTS:

File Compression Level = Default

Option = Standard

END

END

SOLVER CONTROL:

Turbulence Numerics = First Order

ADVECTION SCHEME:

Option = High Resolution

END

CONVERGENCE CONTROL:

Length Scale Option = Conservative

Maximum Number of Iterations = 100

Minimum Number of Iterations = 1

Timescale Control = Auto Timescale

Timescale Factor = 1.0

END

CONVERGENCE CRITERIA:

Residual Target = 1.E-4

Residual Type = RMS

END

DYNAMIC MODEL CONTROL:

Global Dynamic Model Control = On

END

PARTICLE CONTROL:

PARTICLE INTEGRATION:

Option = Forward Euler

END

END

END

END

COMMAND FILE:

Version = 14.0

Results Version = 14.0

END

SIMULATION CONTROL:

EXECUTION CONTROL:

EXECUTABLE SELECTION:

Double Precision = Off

END

INTERPOLATOR STEP CONTROL:

Runtime Priority = Standard

MEMORY CONTROL:

Memory Allocation Factor = 1.0

END

END

PARALLEL HOST LIBRARY:

HOST DEFINITION: mechfran

Host Architecture String = winnt-amd64

Installation Root = C:\Program Files\ANSYS Inc\v%v\CFX

END

END

PARTITIONER STEP CONTROL:

Multidomain Option = Independent Partitioning

Runtime Priority = Standard

EXECUTABLE SELECTION:

Use Large Problem Partitioner = Off

END

MEMORY CONTROL:

Memory Allocation Factor = 1.0

END

PARTITIONING TYPE:

MeTiS Type = k-way

Option = MeTiS

Partition Size Rule = Automatic

END

END

RUN DEFINITION:

Run Mode = Full

Solver Input File = Fluid Flow CFX_001.res

END

SOLVER STEP CONTROL:

Runtime Priority = Standard

MEMORY CONTROL:

Memory Allocation Factor = 1.0

END

PARALLEL ENVIRONMENT:

Number of Processes = 1

Start Method = Serial

END

END

END

END

[kmgraju]

any suggesstion please
Thank you

kmgraju

[ghorrocks]

Have you done the CFX tutorials? There are several examples of particle flows.

Please post an image of your model, and what you expect the flow to do.

[kmgraju]

Thank you Mr Glenn

I have gone through flow through butterfly valve . Any other tutorial??
Thank you

Govind

[ghorrocks]

All the tutorials are useful, and there are a few others which use particle tracking. Have a look through the contents page of the tutorial manual.

[kmgraju]

Originally Posted by ghorrocks

All the tutorials are useful, and there are a few others which use particle tracking. Have a look through the contents page of the tutorial manual.

Dear friend

please find the geometry which I have created to trap the soot particle
Kindly let me know my mistakes in the setting . I could not locate my mistakes

Thank you for your kind help

Regards

Govind

[ghorrocks]

I do not have time to get your simulation working for you. You are going to have to do the debugging yourself.

But I can see you set wall restitution factors. This means the particles will bounce when they hit the wall, not stick.

[kmgraju]

Dear friend

I would like to calculate the deposition of the soot particles. how do I know that soot has been deposited on the wall or not?
Thank you

Govind

[ghorrocks]

First of all you have to decide what the physics of deposition is. Do the soot particles just stick to the wall if they hit it? At the length scale of soot I doubt this is accurate, all sorts of forces become important for tiny particles at small length scales and you will need to know how to deal with this for an accurate model.

But you do not care about accuracy and just want imaginary soot sticking to an imaginary wall (with the expected imaginery accuracy) then just put a zero coefficient of restitution onto the walls you want soot to stick to.

[SJSW]

You can try to set Boundary Cond. Type to "reflect" and Discrete Phase Reflection Coefficients(Normal and Tangent) to 0.
If you choose "trap", the particle will be removed and not displayed, but its current mass and energy is imparted to the gas phase.