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-   -   sonicTurbDyMEngineFoam (http://www.cfd-online.com/Forums/openfoam/112447-sonicturbdymenginefoam.html)

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

Thanks for your reply peter,

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


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