src/lagrangian/spray/submodels/AtomizationModel/LISAAtomization/LISAAtomization.C

   1 /*---------------------------------------------------------------------------*\
   2   =========                 |
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   7 -------------------------------------------------------------------------------
   8 License
   9     This file is part of OpenFOAM.
  10
  11     OpenFOAM is free software: you can redistribute it and/or modify it
  12     under the terms of the GNU General Public License as published by
  13     the Free Software Foundation, either version 3 of the License, or
  14     (at your option) any later version.
  15
  16     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
  17     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  19     for more details.
  20
  21     You should have received a copy of the GNU General Public License
  22     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 \*---------------------------------------------------------------------------*/
  25
  26 #include "LISAAtomization.H"
  27
  28 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
  29
  30 template <class CloudType>
  31 Foam::LISAAtomization<CloudType>::LISAAtomization
  32 (
  33     const dictionary& dict,
  34     CloudType& owner
  35 )
  36 :
  37     AtomizationModel<CloudType>(dict, owner, typeName),
  38     Cl_(readScalar(this->coeffDict().lookup("Cl"))),
  39     cTau_(readScalar(this->coeffDict().lookup("cTau"))),
  40     Q_(readScalar(this->coeffDict().lookup("Q"))),
  41     lisaExp_(readScalar(this->coeffDict().lookup("lisaExp"))),
  42     injectorDirection_(this->coeffDict().lookup("injectorDirection")),
  43     SMDCalcMethod_(this->coeffDict().lookup("SMDCalculationMethod"))
  44 {
  45     // Note: Would be good if this could be picked up from the injector
  46     injectorDirection_ /= mag(injectorDirection_);
  47
  48     if (SMDCalcMethod_ == "method1")
  49     {
  50         SMDMethod_ = method1;
  51     }
  52     else if (SMDCalcMethod_ == "method2")
  53     {
  54         SMDMethod_ = method2;
  55     }
  56     else
  57     {
  58         SMDMethod_ = method2;
  59         Info<< "Warning: SMDCalculationMethod " << SMDCalcMethod_
  60             << " unknown. Options are (method1 | method2). Using method2"
  61             << endl;
  62     }
  63 }
  64
  65 template <class CloudType>
  66 Foam::LISAAtomization<CloudType>::LISAAtomization
  67 (
  68     const LISAAtomization<CloudType>& am
  69 )
  70 :
  71     AtomizationModel<CloudType>(am),
  72     Cl_(am.Cl_),
  73     cTau_(am.cTau_),
  74     Q_(am.Q_),
  75     lisaExp_(am.lisaExp_),
  76     injectorDirection_(am.injectorDirection_),
  77     SMDCalcMethod_(am.SMDCalcMethod_)
  78 {}
  79
  80
  81 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
  82
  83 template <class CloudType>
  84 Foam::LISAAtomization<CloudType>::~LISAAtomization()
  85 {}
  86
  87
  88 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
  89
  90 template<class CloudType>
  91 Foam::scalar Foam::LISAAtomization<CloudType>::initLiquidCore() const
  92 {
  93     return 1.0;
  94 }
  95
  96
  97 template<class CloudType>
  98 bool Foam::LISAAtomization<CloudType>::calcChi() const
  99 {
 100     return true;
 101 }
 102
 103
 104 template<class CloudType>
 105 void Foam::LISAAtomization<CloudType>::update
 106 (
 107     const scalar dt,
 108     scalar& d,
 109     scalar& liquidCore,
 110     scalar& tc,
 111     const scalar rho,
 112     const scalar mu,
 113     const scalar sigma,
 114     const scalar volFlowRate,
 115     const scalar rhoAv,
 116     const scalar Urel,
 117     const vector& pos,
 118     const vector& injectionPos,
 119     const scalar pAmbient,
 120     const scalar chi,
 121     cachedRandom& rndGen
 122 ) const
 123 {
 124     if (volFlowRate < SMALL)
 125     {
 126         return;
 127     }
 128
 129     scalar tau = 0.0;
 130     scalar dL = 0.0;
 131     scalar k = 0.0;
 132
 133     // update atomization characteristic time
 134     tc += dt;
 135
 136     scalar We = 0.5*rhoAv*sqr(Urel)*d/sigma;
 137     scalar nu = mu/rho;
 138
 139     scalar Q = rhoAv/rho;
 140
 141     vector diff = pos - injectionPos;
 142     scalar pWalk = mag(diff);
 143     scalar traveledTime = pWalk/Urel;
 144
 145     scalar h = diff & injectorDirection_;
 146     scalar delta = sqrt(sqr(pWalk) - sqr(h));
 147
 148     scalar hSheet = volFlowRate/(constant::mathematical::pi*delta*Urel);
 149
 150     // update drop diameter
 151     d = min(d, hSheet);
 152
 153     if (We > 27.0/16.0)
 154     {
 155         scalar kPos = 0.0;
 156         scalar kNeg = Q*sqr(Urel)*rho/sigma;
 157
 158         scalar derivPos = sqrt(Q*sqr(Urel));
 159
 160         scalar derivNeg =
 161             (
 162                 8.0*sqr(nu)*pow3(kNeg)
 163               + Q*sqr(Urel)*kNeg
 164               - 3.0*sigma/2.0/rho*sqr(kNeg)
 165             )
 166           / sqrt
 167             (
 168                 4.0*sqr(nu)*pow4(kNeg)
 169               + Q*sqr(Urel)*sqr(kNeg)
 170               - sigma*pow3(kNeg)/rho
 171             )
 172           - 4.0*nu*kNeg;
 173
 174         scalar kOld = 0.0;
 175
 176         for (label i=0; i<40; i++)
 177         {
 178             k = kPos - (derivPos/((derivNeg - derivPos)/(kNeg - kPos)));
 179
 180             scalar derivk =
 181                 (
 182                     8.0*sqr(nu)*pow3(k)
 183                   + Q*sqr(Urel)*k
 184                   - 3.0*sigma/2.0/rho*sqr(k)
 185                 )
 186               / sqrt
 187                 (
 188                     4.0*sqr(nu)*pow4(k)
 189                   + Q*sqr(Urel)*sqr(k)
 190                   - sigma*pow3(k)/rho
 191                 )
 192               - 4.0*nu*k;
 193
 194             if (derivk > 0)
 195             {
 196                 derivPos = derivk;
 197                 kPos = k;
 198             }
 199             else
 200             {
 201                 derivNeg = derivk;
 202                 kNeg = k;
 203             }
 204
 205             if (mag(k - kOld)/k < 1e-4)
 206             {
 207                 break;
 208             }
 209
 210             kOld = k;
 211         }
 212
 213         scalar omegaS =
 214           - 2.0*nu*sqr(k)
 215           + sqrt
 216             (
 217                 4.0*sqr(nu)*pow4(k)
 218               + Q*sqr(Urel)*sqr(k)
 219               - sigma*pow3(k)/rho
 220             );
 221
 222         tau = cTau_/omegaS;
 223
 224         dL = sqrt(8.0*d/k);
 225     }
 226     else
 227     {
 228         k = rhoAv*sqr(Urel)/2.0*sigma;
 229
 230         scalar J = 0.5*traveledTime*hSheet;
 231
 232         tau = pow(3.0*cTau_, 2.0/3.0)*cbrt(J*sigma/(sqr(Q)*pow4(Urel)*rho));
 233
 234         dL = sqrt(4.0*d/k);
 235     }
 236
 237     scalar kL = 1.0/(dL*sqrt(0.5 + 1.5 * mu/sqrt(rho*sigma*dL)));
 238
 239     scalar dD = cbrt(3.0*constant::mathematical::pi*sqr(dL)/kL);
 240
 241     scalar atmPressure = 1.0e+5;
 242
 243     scalar pRatio = pAmbient/atmPressure;
 244
 245     dD = dD*pow(pRatio, lisaExp_);
 246
 247     scalar pExp = 0.135;
 248
 249     //  modifing dD to take account of flash boiling
 250     dD = dD*(1.0 - chi*pow(pRatio, -pExp));
 251     scalar lBU = Cl_ * mag(Urel)*tau;
 252
 253     if (pWalk > lBU)
 254     {
 255         scalar x = 0;
 256
 257         switch (SMDMethod_)
 258         {
 259             case method1:
 260             {
 261                 #include "LISASMDCalcMethod1.H"
 262                 break;
 263             }
 264             case method2:
 265             {
 266                 #include "LISASMDCalcMethod2.H"
 267                 break;
 268             }
 269         }
 270
 271         //  New droplet properties
 272         liquidCore = 0.0;
 273         d = x;
 274         tc = 0.0;
 275     }
 276 }
 277
 278
 279 // ************************************************************************* //