blobsSwirlInjector.C

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/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 1991-2010 OpenCFD Ltd.
     \\/     M anipulation  |
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#include "blobsSwirlInjector.H"
#include <OpenFOAM/addToRunTimeSelectionTable.H>
#include <OpenFOAM/mathematicalConstants.H>

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

defineTypeNameAndDebug(blobsSwirlInjector, 0);

addToRunTimeSelectionTable
(
    injectorModel,
    blobsSwirlInjector,
    dictionary
);


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

// Construct from components
blobsSwirlInjector::blobsSwirlInjector
(
    const dictionary& dict,
    spray& sm
)
:
    injectorModel(dict, sm),
    blobsSwirlInjectorDict_(dict.subDict(typeName + "Coeffs")),

    coneAngle_(blobsSwirlInjectorDict_.lookup("ConeAngle")),
    coneInterval_(blobsSwirlInjectorDict_.lookup("ConeInterval")),

    cD_(blobsSwirlInjectorDict_.lookup("cD")),
    cTau_(blobsSwirlInjectorDict_.lookup("cTau")),
    A_(blobsSwirlInjectorDict_.lookup("A")),
    
    angle_(0.0),
    u_(0.0),
    x_(0.0),
    h_(0.0)
{

    if (sm.injectors().size() != coneAngle_.size())
    {
        FatalError << "blobsSwirlInjector::blobsSwirlInjector"
            << "(const dictionary& dict, spray& sm)\n"
            << "Wrong number of entries in innerAngle"
            << abort(FatalError);
    }

    scalar referencePressure = sm.p().average().value();

    // correct velocityProfile
    forAll(sm.injectors(), i)
    {
        sm.injectors()[i].properties()->correctProfiles(sm.fuels(), referencePressure);
    }

}


// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //

blobsSwirlInjector::~blobsSwirlInjector()
{}


// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

scalar blobsSwirlInjector::d0
(
    const label n, 
    const scalar t
) const
{
    const injectorType& it = injectors_[n].properties();

    scalar c = rndGen_.scalar01();

    angle_ = coneAngle_[n]/2.0 + c * coneInterval_[n];

    angle_ *= mathematicalConstant::pi/180.0;

    scalar injectedMassFlow = it.massFlowRate(t);
    
    scalar cosAngle = cos(angle_);   

    scalar rhoFuel = sm_.fuels().rho(sm_.ambientPressure(), it.T(t), it.X()); 
     
    scalar deltaPressure = deltaPressureInj(t,n);

    calculateHX(n, injectedMassFlow, deltaPressure, t);
    
    scalar kV = kv(n);
    
    scalar v = kV * sqrt(2.0*deltaPressure/rhoFuel);    

    u_ = v * cosAngle;
    
    return h_;
    
}

vector blobsSwirlInjector::direction
(
    const label n,
    const label hole,
    const scalar time,
    const scalar d
) const
{

    scalar alpha = sin(angle_);
    scalar dcorr = cos(angle_);
    scalar beta = 2.0*mathematicalConstant::pi*rndGen_.scalar01();

    // randomly distributed vector normal to the injection vector
    vector normal = vector::zero;
    
    if (sm_.twoD())
    {
        scalar reduce = 0.01;
        // correct beta if this is a 2D run
        // map it onto the 'angleOfWedge'

        beta *= (1.0-2.0*reduce)*sm_.angleOfWedge()/(2.0*mathematicalConstant::pi);
        beta += reduce*sm_.angleOfWedge();
        normal = alpha*
        (
            sm_.axisOfWedge()*cos(beta) +
            sm_.axisOfWedgeNormal()*sin(beta)
        );
    }
    else
    {
        normal = alpha*
        (
            injectors_[n].properties()->tan1(hole)*cos(beta) +
            injectors_[n].properties()->tan2(hole)*sin(beta)
        );
    }
    
    // set the direction of injection by adding the normal vector
    vector dir = dcorr*injectors_[n].properties()->direction(hole, time) + normal;
    dir /= mag(dir);

    return dir;
}


scalar blobsSwirlInjector::velocity
(
    const label i,
    const scalar time
) const
{
    return u_*sqrt(1.0 + pow(tan(angle_),2.0));
}

scalar blobsSwirlInjector::averageVelocity
(
    const label i
) const
{    

    const injectorType& it = sm_.injectors()[i].properties();

    scalar dt = it.teoi() - it.tsoi();


    scalar injectionPressure = averagePressure(i);

    scalar Tav = it.integrateTable(it.T())/dt;
    scalar rhoFuel = sm_.fuels().rho(sm_.ambientPressure(), Tav, it.X());  

    scalar kV = kv(i);

    return  kV*sqrt(2.0*(injectionPressure-sm_.ambientPressure())/rhoFuel);

}


scalar blobsSwirlInjector::kv
(
    const label inj
) const
{
    return cD_[inj]/cos(angle_) * sqrt((1.0 - x_)/(1.0 + x_));    
}

void blobsSwirlInjector::calculateHX
(
    const label inj,
    const scalar massFlow,
    const scalar dPressure,
    const scalar time
) const
{

    const injectorType& it = injectors_[inj].properties();

    scalar Tfuel = it.T(time);
    scalar rhoFuel = sm_.fuels().rho(sm_.ambientPressure(), Tfuel, it.X()); 
    scalar muFuel = sm_.fuels().mu(sm_.ambientPressure(), Tfuel, it.X()); 
    scalar injectorDiameter = it.d();  

    x_ = 0.0;
    
    h_ = 
    sqrt
    (
        (
            A_[inj] *
            cTau_[inj] *
            muFuel*
            massFlow*
            (1.0 + x_)
        )
        /
        (
            mathematicalConstant::pi*
            injectorDiameter*
            rhoFuel*
            dPressure*
            sqr(1.0 - x_)
        )
    );
    
    scalar hOLD = -100.0;
    scalar xOLD = -100.0;
    
    label i;
    
    for(i=0; i<20; i++)
    {


        h_ = 
        sqrt
        (
            (
                A_[inj] *
                cTau_[inj] *
                muFuel*
                massFlow*
                (1.0 + x_)
            )
            /
            (
                mathematicalConstant::pi*
                injectorDiameter*
                rhoFuel*
                dPressure*
                sqr(1.0 - x_)
            )
        );

        x_ = sqr(1.0 - 2.0 * h_/injectorDiameter);

        hOLD = h_;
        xOLD = x_;
                   
    }

    x_ = sqr(1.0 - 2.0 * h_/injectorDiameter);
      
}



scalar blobsSwirlInjector::deltaPressureInj(const scalar time, const label inj) const
{
    return injectors_[inj].properties()->injectionPressure(time) - sm_.ambientPressure();   
}

scalar blobsSwirlInjector::averagePressure(const label inj) const
{

    const injectorType& it = sm_.injectors()[inj].properties();

    scalar dt = it.teoi() - it.tsoi();
    return it.integrateTable(it.injectionPressureProfile())/dt;
}

} // End namespace Foam

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