Date started: 03/11/2003
Purpose: This module models a turbine engine.
- ------------- Copyright (C) 2003 David Culp (davidculp2@attbi.com) -----------
+ ------------- Copyright (C) 2003 David Culp (davidculp2@comcast.net) ---------
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
HISTORY
--------------------------------------------------------------------------------
03/11/2003 DPC Created
+09/08/2003 DPC Changed Calculate() and added engine phases
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// The main purpose of Calculate() is to determine what phase the engine should
+// be in, then call the corresponding function.
double FGSimTurbine::Calculate(double dummy)
{
- double idlethrust, milthrust, thrust;
- double TAT = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556;
+ TAT = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556;
dt = State->Getdt() * Propulsion->GetRate();
-
- // calculate virtual throttle position (actual +/- lag) based on
- // FCS Throttle value (except when trimming)
- if (dt > 0.0) {
- Running = !Starved;
- ThrottleCmd = FCS->GetThrottleCmd(EngineNumber);
- if ( ThrottleCmd > throttle ) {
- throttle += (dt * delay);
- if (throttle > ThrottleCmd ) throttle = ThrottleCmd;
+ ThrottleCmd = FCS->GetThrottleCmd(EngineNumber);
+
+ // 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 = TAT + 10;
+ Cutoff = false;
}
else {
- throttle -= (dt * delay * 3.0);
- if (throttle < ThrottleCmd ) throttle = ThrottleCmd;
+ phase = tpOff;
+ Cutoff = true;
+ EGT_degC = TAT;
}
}
- else {
- Starved = false;
- throttle = ThrottleCmd = FCS->GetThrottleCmd(EngineNumber);
- }
-
- idlethrust = MaxMilThrust * ThrustTables[0]->TotalValue();
- milthrust = MaxMilThrust * ThrustTables[1]->TotalValue();
+
+ 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();
+ }
+
+ return Thrust;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::Off(void)
+{
+ double qbar = Translation->Getqbar();
+ Running = false;
+ FuelFlow_pph = 0.0;
+ 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;
+ EPR = 1.0;
+ return 0.0;
+}
- if (Running) {
- thrust = milthrust * throttle * throttle;
- if (thrust < idlethrust) thrust = idlethrust;
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::Run(void)
+{
+ double idlethrust, milthrust, thrust;
+ double N2norm; // 0.0 = idle N2, 1.0 = maximum N2
+ idlethrust = MaxMilThrust * ThrustTables[0]->TotalValue();
+ milthrust = (MaxMilThrust - idlethrust) * ThrustTables[1]->TotalValue();
+
+ Running = true;
+ Starter = false;
+
+ N2 = Seek(&N2, IdleN2 + ThrottleCmd * N2_factor, delay, delay * 3.0);
+ N1 = Seek(&N1, IdleN1 + ThrottleCmd * N1_factor, delay, delay * 2.4);
+ N2norm = (N2 - IdleN2) / N2_factor;
+ thrust = idlethrust + (milthrust * N2norm * N2norm);
FuelFlow_pph = thrust * TSFC;
thrust = thrust * (1.0 - BleedDemand);
- IdleFF = pow(MaxMilThrust, 0.2) * 107.0;
if (FuelFlow_pph < IdleFF) FuelFlow_pph = IdleFF;
- N1 = IdleN1 + throttle * N1_factor;
- N2 = IdleN2 + throttle * N2_factor;
EGT_degC = TAT + 363.1 + ThrottleCmd * 357.1;
OilPressure_psi = N2 * 0.62;
- OilTemp_degK += dt * 1.2;
- if (OilTemp_degK > 366.0) OilTemp_degK = 366.0;
+ OilTemp_degK = Seek(&OilTemp_degK, 366.0, 1.2, 0);
EPR = 1.0 + thrust/MaxMilThrust;
- NozzlePosition = 1.0 - throttle;
+ NozzlePosition = Seek(&NozzlePosition, 1.0 - N2norm, 0.8, 0.8);
if (Reversed) thrust = thrust * -0.2;
- }
- else {
- thrust = 0.0;
- FuelFlow_pph = 0.000001;
- N1 -= (dt * 3.0);
- if (N1 < (Translation->Getqbar()/10.0)) N1 = Translation->Getqbar()/10.0;
- N2 -= (dt * 3.5);
- if (N2 < (Translation->Getqbar()/15.0)) N2 = Translation->Getqbar()/15.0;
- EGT_degC -= (dt * 11.7);
- if (EGT_degC < TAT) EGT_degC = TAT;
+
+ if (AugMethod == 1) {
+ if ((ThrottleCmd > 0.99) && (N2 > 97.0)) {Augmentation = true;}
+ else {Augmentation = false;}
+ }
+
+ if ((Augmented == 1) && Augmentation) {
+ thrust = thrust * ThrustTables[2]->TotalValue();
+ FuelFlow_pph = thrust * ATSFC;
+ NozzlePosition = Seek(&NozzlePosition, 1.0, 0.8, 0);
+ }
+
+ if ((Injected == 1) && Injection)
+ thrust = thrust * ThrustTables[3]->TotalValue();
+
+ ConsumeFuel();
+ if (Cutoff) phase = tpOff;
+ if (Starved) phase = tpOff;
+ return thrust;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::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 = TAT;
OilPressure_psi = N2 * 0.62;
- OilTemp_degK -= (dt * 0.2);
- if (OilTemp_degK < (TAT + 273.0)) OilTemp_degK = (TAT + 273.0);
+ OilTemp_degK = TAT + 273.0;
EPR = 1.0;
- }
+ NozzlePosition = 1.0;
+ return 0.0;
+}
- if (AugMethod == 1) {
- if (throttle > 0.99) {Augmentation = true;}
- else {Augmentation = false;}
- }
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
- if ((Augmented == 1) && Augmentation) {
- thrust = thrust * ThrustTables[2]->TotalValue();
- FuelFlow_pph = thrust * ATSFC;
- NozzlePosition = 1.0;
- }
+double FGSimTurbine::Start(void)
+{
+ if ((N2 > 15.0) && !Starved) { // minimum 15% N2 needed for start
+ Cranking = true;
+ 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;
+ }
+ else {
+ phase = tpRun;
+ Running = true;
+ Starter = false;
+ Cranking = false;
+ }
+ }
+ else { // no start if N2 < 15%
+ phase = tpOff;
+ Starter = false;
+ }
+ return 0.0;
+}
- if ((Injected == 1) && Injection)
- thrust = thrust * ThrustTables[3]->TotalValue();
-
- ConsumeFuel();
-
- return Thrust = thrust;
-
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::Stall(void)
+{
+ double qbar = Translation->Getqbar();
+ EGT_degC = TAT + 903.14;
+ FuelFlow_pph = IdleFF;
+ N1 = Seek(&N1, qbar/10.0, 0, N1/10.0);
+ N2 = Seek(&N2, qbar/15.0, 0, N2/10.0);
+ if (ThrottleCmd == 0) phase = tpRun; // clear the stall with throttle
+ return 0.0;
}
-
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::Seize(void)
+{
+ double qbar = Translation->Getqbar();
+ N2 = 0.0;
+ N1 = Seek(&N1, qbar/20.0, 0, N1/15.0);
+ FuelFlow_pph = IdleFF;
+ OilPressure_psi = 0.0;
+ OilTemp_degK = Seek(&OilTemp_degK, TAT + 273.0, 0, 0.2);
+ Running = false;
+ return 0.0;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::Trim(void)
+{
+ double idlethrust, milthrust, thrust;
+ idlethrust = MaxMilThrust * ThrustTables[0]->TotalValue();
+ milthrust = (MaxMilThrust - idlethrust) * ThrustTables[1]->TotalValue();
+ thrust = idlethrust + (milthrust * ThrottleCmd * ThrottleCmd);
+ return thrust;
+}
+
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
double FGSimTurbine::CalcFuelNeed(void)
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
double FGSimTurbine::GetPowerAvailable(void) {
- if( throttle <= 0.77 )
- return 64.94*throttle;
+ if( ThrottleCmd <= 0.77 )
+ return 64.94*ThrottleCmd;
else
- return 217.38*throttle - 117.38;
+ return 217.38*ThrottleCmd - 117.38;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGSimTurbine::Seek(double *var, double target, double accel, double decel) {
+ double v = *var;
+ if (v > target) {
+ v -= dt * decel;
+ if (v < target) v = target;
+ } else if (v < target) {
+ v += dt * accel;
+ if (v > target) v = target;
+ }
+ return v;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
AugMethod = 0;
Injected = 0;
BleedDemand = 0.0;
- throttle = 0.0;
+ ThrottleCmd = 0.0;
InletPosition = 1.0;
NozzlePosition = 1.0;
Augmentation = false;
Injection = false;
Reversed = false;
+ phase = tpOff;
+ Stalled = false;
+ Seized = false;
+ Overtemp = false;
+ Fire = false;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
}
// pre-calculations and initializations
- delay= 1.0 / (BypassRatio + 3.0);
+ delay= 60.0 / (BypassRatio + 3.0);
N1_factor = MaxN1 - IdleN1;
N2_factor = MaxN2 - IdleN2;
OilTemp_degK = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556 + 273.0;
IdleFF = pow(MaxMilThrust, 0.2) * 107.0; // just an estimate
- AddFeedTank(EngineNumber); // engine[n] feeds from tank[n]
return true;
}
Author: David Culp
Date started: 03/11/2003
- ------------- Copyright (C) 2003 David Culp (davidculp2@attbi.com)------------
+ ------------- Copyright (C) 2003 David Culp (davidculp2@comcast.net)----------
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
HISTORY
--------------------------------------------------------------------------------
03/11/2003 DPC Created
+09/22/2003 DPC Added starting, stopping
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
COMMENTS, REFERENCES, and NOTES
FGSimTurbine(FGFDMExec* exec, FGConfigFile* Eng_cfg);
~FGSimTurbine();
+ enum phaseType { tpOff, tpRun, tpSpinUp, tpStart, tpStall, tpSeize, tpTrim };
+
double Calculate(double);
double CalcFuelNeed(void);
double GetPowerAvailable(void);
+ double Seek(double* var, double target, double accel, double decel);
+
+ virtual phaseType GetPhase(void) { return phase; }
+ virtual void SetPhase( phaseType p ) { phase = p; }
+
+ virtual bool GetOvertemp(void) { return Overtemp; }
+ virtual bool GetFire(void) { return Fire; }
private:
typedef vector<FGCoefficient*> CoeffArray;
CoeffArray ThrustTables;
+ phaseType phase; // Operating mode, or "phase"
double MaxMilThrust; // Maximum Rated Thrust, static @ S.L. (lbf)
double BypassRatio; // Bypass Ratio
double TSFC; // Thrust Specific Fuel Consumption (lbm/hr/lbf)
double N2_factor; // factor to tie N2 and throttle
double ThrottleCmd; // FCS-supplied throttle position
double throttle; // virtual throttle position
+ double TAT; // total air temperature (deg C)
+ bool Stalled; // true if engine is compressor-stalled
+ bool Seized; // true if inner spool is seized
+ bool Overtemp; // true if EGT exceeds limits
+ bool Fire; // true if engine fire detected
+ bool start_running; // true if user wants engine running at start
int Augmented; // = 1 if augmentation installed
int Injected; // = 1 if water injection installed
int AugMethod; // = 0 if using property /engine[n]/augmentation
// = 1 if using last 1% of throttle movement
+ double Off(void);
+ double Run(void);
+ double SpinUp(void);
+ double Start(void);
+ double Stall(void);
+ double Seize(void);
+ double Trim(void);
+
void SetDefaults(void);
bool Load(FGConfigFile *ENG_cfg);
void Debug(int from);
projects / flightgear.git / commitdiff