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 sasanghomi January 29, 2013 04:23

Opening soon the exhaust valve "sonicTurbDyMEngineFoam"

Hi every body,

I have a problem with a case for coldFlow in an internal combustion engine (sonicTurbDyMEngineFoam )....the exhaust valve opens early (about 0.005 (s) ).Can any one help me????
How do I correct it???

thanks,
Sasan

 wyldckat January 29, 2013 05:35

Greetings Sasan,

Can you please provide more information? The reason I ask is because you're not providing enough information, as indicated in this thread: http://www.cfd-online.com/Forums/ope...-get-help.html

Best regards,
Bruno

PS: don't mind about the other post with strange characters, it was just a spammer...

 sasanghomi January 29, 2013 07:16

Opening soon the exhaust valve "sonicTurbDyMEngineFoam"

1 Attachment(s)
Hi wyldckat ,
Thank you very much.
I am running a case that it simulates the cold flow in an internal combustion engine.
The solver is sonicTurbDyMEngineFoam.The rotational velocity is (rpm=1500), So the total time for a cycle of the engine is 0.08(s).I expect that the exhaust valve opens at 0.06(s)
but when I plot the mass flow versus time at the exhaust port I saw that the exhaust valve opened at 0.055(s).How do I can correct this problem???please any one help me....

The engineGeometry is as below :

Code:

```/*--------------------------------*- C++ -*----------------------------------*\ | =========                |                                                | | \\      /  F ield        | OpenFOAM Extend Project: Open Source CFD        | |  \\    /  O peration    | Version:  1.6-ext                              | |  \\  /    A nd          | Web:      www.extend-project.de                | |    \\/    M anipulation  |                                                | \*---------------------------------------------------------------------------*/ FoamFile {     version    2.0;     format      ascii;     class      dictionary;     object      engineGeometry; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // conRodLength    conRodLength [0 1 0 0 0 0 0] 0.147; bore            bore [0 1 0 0 0 0 0] 0.092; stroke          stroke [0 1 0 0 0 0 0] 0.075; clearance      clearance [0 1 0 0 0 0 0] 0.015; rpm            rpm [0 0 -1 0 0 0 0] 1500; engineTopoChangerMesh  simpleEngineTopoFvMesh; // Between -deformAngle and deformAngle the piston motion is done // using deformation and not layering deformAngle    10; valvePosTol    1e-4; layeredMesh    yes; checkMesh      yes; piston {     patch              piston;     coordinateSystem     {         type            cartesian;         origin          (0 0 0);         axis            (0 0 1);         direction      (0 1 0);     }     minLayer        0.0005;     maxLayer        0.001; } valveSplitPoint    (0.003 0 0);    // For the converter // Two-valve engine valves are split on x // Four valve engines are split into 4 quadrants in the x-y plane valves (     intakeValve     {         // Valve coordinate system         coordinateSystem         {             type            cylindrical;             origin          (-0.025 0 0);             axis            (0 0 1);             direction      (0 1 0);         }         // Patch  and zone names         bottomPatch            valve1;         poppetPatch            valve2;         stemPatch              valveStem1;         curtainInPortPatch      valveCurtainPort1;         curtainInCylinderPatch  valveCurtainCyl1;         detachInCylinderPatch  valveDetachCyl1;         detachInPortPatch      valveDetachPort1;         detachFaces         ( 2593 2595 2597 2599 2601 2603 2605 2607 2609 2611 2613 2615 2617 2619 2621 2623 2625 2627 2629 2630         );         // Vertex on edge of the step.  For the converter         stemEdge            (-0.04 0 -0.0075);         // Valve diameter         diameter            0.03;         // Minimum valve lift         minLift            0.00025;         // Layer thickness         minTopLayer        0.0005;         maxTopLayer        0.001;         minBottomLayer      0.0005;         maxBottomLayer      0.001;         // Lift Profile         liftProfileFile "intakeLiftProfileFile";     }     exhaustValve     {         // Valve coordinate system         coordinateSystem         {             type            cylindrical;             origin          (0.025 0 0);             axis            (0 0 1);             direction      (0 1 0);         }         // Patch  and zone names         bottomPatch            valve3;         poppetPatch            valve4;         stemPatch              valveStem2;         curtainInPortPatch      valveCurtainPort2;         curtainInCylinderPatch  valveCurtainCyl2;         detachInCylinderPatch  valveDetachCyl2;         detachInPortPatch      valveDetachPort2;         detachFaces         ( 4854 4856 4858 4860 4862 4864 4866 4868 4870 4872 4874 4876 4878 4880 4882 4884 4886 4888 4890 4891         );         // Vertex on edge of the step.  For the converter         stemEdge          (0.04 0 -0.0075);         // Valve diameter         diameter            0.03;         // Minimum valve lift         minLift            0.00025;         // Layer thickness         minTopLayer        0.0005;         maxTopLayer        0.001;         minBottomLayer      0.0005;         maxBottomLayer      0.001;         // Lift Profile         liftProfileFile "exhaustLiftProfileFile";     } ); // ************************************************************************* //```
An image of the case is attached.

Thanks,
Sasan.

 Peter_600 January 29, 2013 09:18

The exhaust will open when the lift exhaust valve lift exceeds 0.0025 as specified in your dictionary.
So it depends on your valve lift profile.

cheers peter

 sasanghomi January 29, 2013 09:39

Can you give me any sources about describtion of minimum valve lift and valve lift profile??
Can you explain them??

thanks,
Sasan.

sasanghomi@yahoo.com

 enginejob October 4, 2016 20:11

hi, i have a problem with this solver too. The error is:

Code:

``` --> FOAM FATAL ERROR: found boundary face in valve detach definition for valve 1.  This is not allowed.  Detach faces: 24 ( 12316 12317 12318 12319 12320 12321 12322 12323 12324 12325 12326 12327 12328 12329 12330 12331 12332 12333 12334 12335 12336 12337 12338 12339 )  nInternalFaces: 12190     From function void simpleEngineTopoFvMesh::addZonesAndModifiers()     in file simpleEngineTopoFvMesh/addSimpleEngineTopoFvMeshModifiers.C at line 188.```
Searching for this function i have found it:

Code:

```// Create a detach zone             if             (                 valves_[valveI].detachInCylinderPatchID().active()             && valves_[valveI].detachInPortPatchID().active()             && valves_[valveI].detachFaces().size() > 0             )             {                 Info<< "Adding detach boundary for valve "                     << valveI + 1 << endl;                 const vectorField& areas = Sf().internalField();                 const labelList& df = valves_[valveI].detachFaces();                 boolList flip(df.size(), false);                 const vector& pistonAxis = piston().cs().axis();                 forAll (df, dfI)                 {                     if (isInternalFace(df[dfI]))                     {                         if ((areas[df[dfI]] & pistonAxis) > 0)                         {                             flip[dfI] = true;                         }                     }                     else                     {                         FatalErrorIn                         (                             "void simpleEngineTopoFvMesh::"                             "addZonesAndModifiers()"                         )  << "found boundary face in valve detach definition"                             << " for valve " << valveI + 1                             << ".  This is not allowed.  Detach faces: "                             << df << " nInternalFaces: " << nInternalFaces()                             << abort(FatalError);                     }                 }```
probably i have some problems with the mesh, right ?
How do i do the mesh at the detach zone ?

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