fgturbine.cpp

6 DOF Missle Simulation

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 Module:       FGTurbine.cpp
 Author:       David Culp
 Date started: 03/11/2003
 Purpose:      This module models a turbine engine.

 ------------- Copyright (C) 2003  David Culp ([e-mail]) ---------

 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by the Free Software
 Foundation; either version 2 of the License, or (at your option) any later
 version.

 This program is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 details.

 You should have received a copy of the GNU Lesser General Public License along with
 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 Place - Suite 330, Boston, MA  02111-1307, USA.

 Further information about the GNU Lesser General Public License can also be found on
 the world wide web at http://www.gnu.org.

FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------

This class descends from the FGEngine class and models a turbine engine based
on parameters given in the engine config file for this class

HISTORY
--------------------------------------------------------------------------------
03/11/2003  DPC  Created
09/08/2003  DPC  Changed Calculate() and added engine phases

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#include <vector>
#include <sstream>

#include "FGTurbine.h"

namespace JSBSim {

static const char *IdSrc = "$Id$";
static const char *IdHdr = ID_TURBINE;

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS IMPLEMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/


FGTurbine::FGTurbine(FGFDMExec* exec, Element *el, int engine_number)
  : FGEngine(exec, el, engine_number)
{
  Type = etTurbine;

  MilThrust = MaxThrust = 10000.0;
  TSFC = 0.8;
  ATSFC = 1.7;
  IdleN1 = 30.0;
  IdleN2 = 60.0;
  MaxN1 = MaxN2 = 100.0;
  Augmented = AugMethod = Injected = 0;
  BypassRatio = BleedDemand = 0.0;
  IdleThrustLookup = MilThrustLookup = MaxThrustLookup = InjectionLookup = 0;

  ResetToIC();

  Load(exec, el);
  Debug(0);
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

FGTurbine::~FGTurbine()
{
  delete IdleThrustLookup;
  delete MilThrustLookup;
  delete MaxThrustLookup;
  delete InjectionLookup;
  Debug(1);
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

void FGTurbine::ResetToIC(void)
{
  N1 = N2 = 0.0;
  correctedTSFC = TSFC;
  ThrottlePos = AugmentCmd = 0.0;
  InletPosition = NozzlePosition = 1.0;
  Stalled = Seized = Overtemp = Fire = Augmentation = Injection = Reversed = false;
  Cutoff = true;
  phase = tpOff;
  EGT_degC = 0.0;
  OilTemp_degK = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556 + 273.0;
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// The main purpose of Calculate() is to determine what phase the engine should
// be in, then call the corresponding function.

double FGTurbine::Calculate(void)
{
  TAT = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556;
  dt = State->Getdt() * Propulsion->GetRate();
  ThrottlePos = FCS->GetThrottlePos(EngineNumber);
  if (ThrottlePos > 1.0) {
    AugmentCmd = ThrottlePos - 1.0;
    ThrottlePos -= AugmentCmd;
  } else {
    AugmentCmd = 0.0;
  }

  // When trimming is finished check if user wants engine OFF or RUNNING
  if ((phase == tpTrim) && (dt > 0)) {
    if (Running && !Starved) {
      phase = tpRun;
      N2 = IdleN2 + ThrottlePos * N2_factor;
      N1 = IdleN1 + ThrottlePos * N1_factor;
      OilTemp_degK = 366.0;
      Cutoff = false;
      }
    else {
      phase = tpOff;
      Cutoff = true;
      EGT_degC = TAT;
      }
    }

  if (!Running && Cutoff && Starter) {
     if (phase == tpOff) phase = tpSpinUp;
     }
  if (!Running && !Cutoff && (N2 > 15.0)) phase = tpStart;
  if (Cutoff && (phase != tpSpinUp)) phase = tpOff;
  if (dt == 0) phase = tpTrim;
  if (Starved) phase = tpOff;
  if (Stalled) phase = tpStall;
  if (Seized) phase = tpSeize;

  switch (phase) {
    case tpOff:    Thrust = Off(); break;
    case tpRun:    Thrust = Run(); break;
    case tpSpinUp: Thrust = SpinUp(); break;
    case tpStart:  Thrust = Start(); break;
    case tpStall:  Thrust = Stall(); break;
    case tpSeize:  Thrust = Seize(); break;
    case tpTrim:   Thrust = Trim(); break;
    default: Thrust = Off();
  }

  Thrust = Thruster->Calculate(Thrust); // allow thruster to modify thrust (i.e. reversing)

  return Thrust;
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

double FGTurbine::Off(void)
{
  double qbar = Auxiliary->Getqbar();
  Running = false;
  FuelFlow_pph = Seek(&FuelFlow_pph, 0, 1000.0, 10000.0);
  N1 = Seek(&N1, qbar/10.0, N1/2.0, N1/2.0);
  N2 = Seek(&N2, qbar/15.0, N2/2.0, N2/2.0);
  EGT_degC = Seek(&EGT_degC, TAT, 11.7, 7.3);
  OilTemp_degK = Seek(&OilTemp_degK, TAT + 273.0, 0.2, 0.2);
  OilPressure_psi = N2 * 0.62;
  NozzlePosition = Seek(&NozzlePosition, 1.0, 0.8, 0.8);
  EPR = Seek(&EPR, 1.0, 0.2, 0.2);
  Augmentation = false;
  ConsumeFuel();  
  return 0.0;
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

double FGTurbine::Run()
{
  double idlethrust, milthrust, thrust;
  double N2norm;   // 0.0 = idle N2, 1.0 = maximum N2

  idlethrust = MilThrust * IdleThrustLookup->GetValue();
  milthrust = (MilThrust - idlethrust) * MilThrustLookup->GetValue();

  Running = true;
  Starter = false;

  N2 = Seek(&N2, IdleN2 + ThrottlePos * N2_factor, delay, delay * 3.0);
  N1 = Seek(&N1, IdleN1 + ThrottlePos * N1_factor, delay, delay * 2.4);
  N2norm = (N2 - IdleN2) / N2_factor;
  thrust = idlethrust + (milthrust * N2norm * N2norm);
  EGT_degC = TAT + 363.1 + ThrottlePos * 357.1;
  OilPressure_psi = N2 * 0.62;
  OilTemp_degK = Seek(&OilTemp_degK, 366.0, 1.2, 0.1);

  if (!Augmentation) {
    correctedTSFC = TSFC * (0.84 + (1-N2norm)*(1-N2norm));
    FuelFlow_pph = Seek(&FuelFlow_pph, thrust * correctedTSFC, 1000.0, 100000);
    if (FuelFlow_pph < IdleFF) FuelFlow_pph = IdleFF;
    NozzlePosition = Seek(&NozzlePosition, 1.0 - N2norm, 0.8, 0.8);
    thrust = thrust * (1.0 - BleedDemand);
    EPR = 1.0 + thrust/MilThrust;
  }

  if (AugMethod == 1) {
    if ((ThrottlePos > 0.99) && (N2 > 97.0)) {Augmentation = true;}
    else {Augmentation = false;}
  }

  if ((Augmented == 1) && Augmentation && (AugMethod < 2)) {
    thrust = MaxThrustLookup->GetValue() * MaxThrust;
    FuelFlow_pph = Seek(&FuelFlow_pph, thrust * ATSFC, 5000.0, 10000.0);
    NozzlePosition = Seek(&NozzlePosition, 1.0, 0.8, 0.8);
  }

  if (AugMethod == 2) {
    if (AugmentCmd > 0.0) {
      Augmentation = true;
      double tdiff = (MaxThrust * MaxThrustLookup->GetValue()) - thrust;
      thrust += (tdiff * AugmentCmd);
      FuelFlow_pph = Seek(&FuelFlow_pph, thrust * ATSFC, 5000.0, 10000.0);
      NozzlePosition = Seek(&NozzlePosition, 1.0, 0.8, 0.8);
    } else {
      Augmentation = false;
    }
  }

  if ((Injected == 1) && Injection) {
    InjectionTimer += dt;
    if (InjectionTimer < InjectionTime) {
       thrust = thrust * InjectionLookup->GetValue();
    } else {
       Injection = false;
    }
  }

  ConsumeFuel();
  if (Cutoff) phase = tpOff;
  if (Starved) phase = tpOff;

  return thrust;
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

double FGTurbine::SpinUp(void)
{
  Running = false;
  FuelFlow_pph = 0.0;
  N2 = Seek(&N2, 25.18, 3.0, N2/2.0);
  N1 = Seek(&N1, 5.21, 1.0, N1/2.0);
  EGT_degC = Seek(&EGT_degC, TAT, 11.7, 7.3);
  OilPressure_psi = N2 * 0.62;
  OilTemp_degK = Seek(&OilTemp_degK, TAT + 273.0, 0.2, 0.2);
  EPR = 1.0;
  NozzlePosition = 1.0;
  return 0.0;
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

double FGTurbine::Start(void)
{
  if ((N2 > 15.0) && !Starved) {       // minimum 15% N2 needed for start
    Cranking = true;                   // provided for sound effects signal
    if (N2 < IdleN2) {
      N2 = Seek(&N2, IdleN2, 2.0, N2/2.0);
      N1 = Seek(&N1, IdleN1, 1.4, N1/2.0);
      EGT_degC = Seek(&EGT_degC, TAT + 363.1, 21.3, 7.3);
      FuelFlow_pph = Seek(&FuelFlow_pph, IdleFF, 103.7, 103.7);
      OilPressure_psi = N2 * 0.62;
      ConsumeFuel();
      }
    else {
      phase = tpRun;
      Running = true;
      Starter = false;
      Cranking = false;
      }
    }
  else {                 // no start if N2 < 15%
    phase = tpOff;
    Starter = false;
    }