fgturboprop.cpp

6 DOF Missle Simulation

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

 Module:       FGTurboProp.cpp
 Author:       Jiri "Javky" Javurek
               based on SimTurbine and Turbine engine from David Culp
 Date started: 05/14/2004
 Purpose:      This module models a turbo propeller engine.

 ------------- Copyright (C) 2004  ([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 Turbo propeller engine
based on parameters given in the engine config file for this class

HISTORY
--------------------------------------------------------------------------------
05/14/2004  Created

//JVK (mark)

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

#include <vector>
#include <sstream>
#include "FGTurboProp.h"

#include "FGPropeller.h"

namespace JSBSim {

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

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

FGTurboProp::FGTurboProp(FGFDMExec* exec, Element *el, int engine_number)
  : FGEngine(exec, el, engine_number)
{
  SetDefaults();

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

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

FGTurboProp::~FGTurboProp()
{
  Debug(1);
}

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

bool FGTurboProp::Load(FGFDMExec* exec, Element *el)
{
  char property_prefix[80];
  snprintf(property_prefix, 80, "propulsion/engine[%u]/", EngineNumber);

  IdleFF=-1;
  MaxStartingTime = 999999; //very big timeout -> infinite
  Ielu_max_torque=-1;

// ToDo: Need to make sure units are properly accounted for below.

  if (el->FindElement("milthrust"))
    MilThrust = el->FindElementValueAsNumberConvertTo("milthrust","LBS");
  if (el->FindElement("idlen1"))
    IdleN1 = el->FindElementValueAsNumber("idlen1");
  if (el->FindElement("idlen2"))
    IdleN2 = el->FindElementValueAsNumber("idlen1");
  if (el->FindElement("maxn1"))
    MaxN1 = el->FindElementValueAsNumber("maxn1");
  if (el->FindElement("maxn2"))
    MaxN2 = el->FindElementValueAsNumber("maxn2");
  if (el->FindElement("betarangeend"))
    BetaRangeThrottleEnd = el->FindElementValueAsNumber("betarangeend")/100.0;
  if (el->FindElement("reversemaxpower"))
    ReverseMaxPower = el->FindElementValueAsNumber("reversemaxpower")/100.0;

  if (el->FindElement("maxpower"))
    MaxPower = el->FindElementValueAsNumber("maxpower");
  if (el->FindElement("idlefuelflow"))
    IdleFF = el->FindElementValueAsNumber("idlefuelflow");
  if (el->FindElement("psfc"))
    PSFC = el->FindElementValueAsNumber("psfc");
  if (el->FindElement("n1idle_max_delay"))
    Idle_Max_Delay = el->FindElementValueAsNumber("n1idle_max_delay");
  if (el->FindElement("maxstartingtime"))
    MaxStartingTime = el->FindElementValueAsNumber("maxstartingtime");
  if (el->FindElement("startern1"))
    StarterN1 = el->FindElementValueAsNumber("startern1");
  if (el->FindElement("ielumaxtorque"))
    Ielu_max_torque = el->FindElementValueAsNumber("ielumaxtorque");
  if (el->FindElement("itt_delay"))
    ITT_Delay = el->FindElementValueAsNumber("itt_delay");

  Element *table_element;
  string name;
  FGPropertyManager* PropertyManager = exec->GetPropertyManager();

  while (true) {
    table_element = el->FindNextElement("table");
    if (!table_element) break;
    name = table_element->GetAttributeValue("name");
    if (name == "EnginePowerVC") {
      EnginePowerVC = new FGTable(PropertyManager, table_element);
    } else if (name == "EnginePowerRPM_N1") {
      EnginePowerRPM_N1 = new FGTable(PropertyManager, table_element);
    } else if (name == "ITT_N1") {
      ITT_N1 = new FGTable(PropertyManager, table_element);
    } else {
      cerr << "Unknown table type: " << name << " in turbine definition." <<
      endl;
    }
  }

  // Pre-calculations and initializations

  delay=1;
  N1_factor = MaxN1 - IdleN1;
  N2_factor = MaxN2 - IdleN2;
  OilTemp_degK = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556 + 273.0;
  if (IdleFF==-1) IdleFF = pow(MilThrust, 0.2) * 107.0;  // just an estimate

  cout << "ENG POWER:" << EnginePowerRPM_N1->GetValue(1200,90) << "\n";

  return true;
}

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

double FGTurboProp::Calculate(void)
{
  TAT = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556;
  dt = State->Getdt() * Propulsion->GetRate();

  ThrottleCmd = FCS->GetThrottleCmd(EngineNumber);

  Prop_RPM = Thruster->GetRPM() * Thruster->GetGearRatio();
  if (Thruster->GetType() == FGThruster::ttPropeller) {
    ((FGPropeller*)Thruster)->SetAdvance(FCS->GetPropAdvance(EngineNumber));
    ((FGPropeller*)Thruster)->SetFeather(FCS->GetPropFeather(EngineNumber));
    ((FGPropeller*)Thruster)->SetReverse(Reversed);
    if (Reversed) {
      ((FGPropeller*)Thruster)->SetReverseCoef(ThrottleCmd);
    } else {
      ((FGPropeller*)Thruster)->SetReverseCoef(0.0);
    }
  }

  if (Reversed) {
    if (ThrottleCmd < BetaRangeThrottleEnd) {
        ThrottleCmd = 0.0;  // idle when in Beta-range
    } else {
      // when reversed:
      ThrottleCmd = (ThrottleCmd-BetaRangeThrottleEnd)/(1-BetaRangeThrottleEnd) * ReverseMaxPower;
    }
  }

  // When trimming is finished check if user wants engine OFF or RUNNING
  if ((phase == tpTrim) && (dt > 0)) {
    if (Running && !Starved) {
      phase = tpRun;
      N2 = IdleN2;
      N1 = IdleN1;
      OilTemp_degK = 366.0;
      Cutoff = false;
    } else {
      phase = tpOff;
      Cutoff = true;
      Eng_ITT_degC = TAT;
      Eng_Temperature = TAT;
      OilTemp_degK = TAT+273.15;
    }
  }

  if (!Running && Starter) {
    if (phase == tpOff) {
      phase = tpSpinUp;
      if (StartTime < 0) StartTime=0;
    }
  }
  if (!Running && !Cutoff && (N1 > 15.0)) {
    phase = tpStart;
    StartTime = -1;
  }
  if (Cutoff && (phase != tpSpinUp)) phase = tpOff;
  if (dt == 0) phase = tpTrim;
  if (Starved) phase = tpOff;
  if (Condition >= 10) {
    phase = tpOff;
    StartTime=-1;
  }

  if (Condition < 1) {
    if (Ielu_max_torque > 0
      && -Ielu_max_torque > ((FGPropeller*)(Thruster))->GetTorque()
      && ThrottleCmd >= OldThrottle ) {
      ThrottleCmd = OldThrottle - 0.1 * dt; //IELU down
      Ielu_intervent = true;
    } else if (Ielu_max_torque > 0 && Ielu_intervent && ThrottleCmd >= OldThrottle) {
      ThrottleCmd = OldThrottle;
      ThrottleCmd = OldThrottle + 0.05 * dt; //IELU up
      Ielu_intervent = true;
    } else {
      Ielu_intervent = false;
    }
  } else {
    Ielu_intervent = false;
  }
  OldThrottle = ThrottleCmd;

  switch (phase) {
    case tpOff:    Eng_HP = Off(); break;
    case tpRun:    Eng_HP = Run(); break;
    case tpSpinUp: Eng_HP = SpinUp(); break;
    case tpStart:  Eng_HP = Start(); break;
    default: Eng_HP = 0;
  }

  //printf ("EngHP: %lf / Requi: %lf\n",Eng_HP,Prop_Required_Power);
  return Thruster->Calculate((Eng_HP * hptoftlbssec)-Thruster->GetPowerRequired());
}

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

double FGTurboProp::Off(void)
{
  double qbar = Auxiliary->Getqbar();
  Running = false; EngStarting = false;

  FuelFlow_pph = Seek(&FuelFlow_pph, 0, 800.0, 800.0);

  //allow the air turn with generator
  N1 = ExpSeek(&N1, qbar/15.0, Idle_Max_Delay*2.5, Idle_Max_Delay * 5);

  OilTemp_degK = ExpSeek(&OilTemp_degK,273.15 + TAT, 400 , 400);

  Eng_Temperature = ExpSeek(&Eng_Temperature,TAT,300,400);
  double ITT_goal = ITT_N1->GetValue(N1,0.1) + ((N1>20) ? 0.0 : (20-N1)/20.0 * Eng_Temperature);
  Eng_ITT_degC  = ExpSeek(&Eng_ITT_degC,ITT_goal,ITT_Delay,ITT_Delay*1.2);

  OilPressure_psi = (N1/100.0*0.25+(0.1-(OilTemp_degK-273.15)*0.1/80.0)*N1/100.0) / 7692.0e-6; //from MPa to psi

  ConsumeFuel(); // for possible setting Starved = false when fuel tank
                 // is refilled (fuel crossfeed etc.)

  if (Prop_RPM>5) return -0.012; // friction in engine when propeller spining (estimate)
  return 0.0;
}

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

double FGTurboProp::Run(void)
{
  double thrust = 0.0, EngPower_HP, eff_coef;
  Running = true; Starter = false; EngStarting = false;

//---
  double old_N1 = N1;
  N1 = ExpSeek(&N1, IdleN1 + ThrottleCmd * N1_factor, Idle_Max_Delay, Idle_Max_Delay * 2.4);

  EngPower_HP = EnginePowerRPM_N1->GetValue(Prop_RPM,N1);