public EngineDataPrefab CalcDataAtPresAndTemp(double combustorPressure, double turbineInletTemp, bool oxRich)
{
//if(oxRich) //start at the higher OF ratios and count down
//{
//
//}
//else
//{
EngineDataPrefab prefab2 = mixtureData[0].CalcData(combustorPressure);
for (int i = 1; i < mixtureData.Length; ++i)
{
EngineDataPrefab prefab1 = mixtureData[i].CalcData(combustorPressure);
if (prefab1.chamberTempK < turbineInletTemp)
{
prefab2 = prefab1;
continue;
}
double indexFactor = turbineInletTemp - prefab1.chamberTempK;
indexFactor /= (prefab2.chamberTempK - prefab1.chamberTempK); //this gives us a pseudo-index factor that can be used to calculate properties between the input data
double desiredOF = (prefab2.OFRatio - prefab1.OFRatio) * indexFactor + prefab1.OFRatio;
return(CalcPrefabData(desiredOF, combustorPressure, i - 1));
}
//}
Debug.LogError("[ProcEngines] Error in data tables, could not solve");
return(new EngineDataPrefab());
}
public EngineDataPrefab CalcPrefabData(double oFRatio, double chamberPres)
{
for (int i = 1; i < mixtureOFRatios.Length; ++i)
{
double oF2 = mixtureOFRatios[i];
if (oF2 < oFRatio)
{
continue;
}
double oF1 = mixtureOFRatios[i - 1];
EngineDataPrefab prefab1, prefab2;
prefab1 = mixtureData[i - 1].CalcData(chamberPres);
prefab2 = mixtureData[i].CalcData(chamberPres);
double indexFactor = oFRatio - oF1;
indexFactor /= (oF2 - oF1); //this gives us a pseudo-index factor that can be used to calculate properties between the input data
EngineDataPrefab results = (prefab2 - prefab1) * indexFactor + prefab1;
return(results);
}
Debug.LogError("[ProcEngines] Error in data tables, could not solve");
return(new EngineDataPrefab());
}
void CalculatePreBurnerParameters(bool runOxRich)
{
double injectorPressureDrop = 0.3; //TODO: make injector pres drop vary with throttle capability, tech level
double regenerativeCoolingPresDrop = 0.15; //TODO: make cooling pres draop vary with cooling needs, tech level
double tankPresMPa = 0.2; //TODO: make variable of some kind;
double preburnerTurbineOutputPresMPa = chamberPresMPa * (1 + injectorPressureDrop);
double preburnerPressureMPa = preburnerTurbineOutputPresMPa * turbinePresRatio; //TODO: allow separate ox, fuel turbines
double oxPumpPresRiseMPa = preburnerPressureMPa - tankPresMPa;
double fuelPumpPresRiseMPa = preburnerPressureMPa * (1 + regenerativeCoolingPresDrop) - tankPresMPa; //assume that only fuel is used for regen cooling
double pumpEfficiency = 0.8; //TODO: make vary with fuel type and with tech level
double oxPumpPower = massFlowChamberOx * oxPumpPresRiseMPa * 1000000 / (propConfig.GetOxDensity() * pumpEfficiency); //convert MPa to Pa, but allow tonnes to cancel
double fuelPumpPower = massFlowChamberFuel * fuelPumpPresRiseMPa * 1000000 / (propConfig.GetFuelDensity() * pumpEfficiency); //convert MPa to Pa, but allow tonnes to cancel
double turbinePowerReq = oxPumpPower + fuelPumpPower;
double turbineEfficiency = 0.7; //TODO: make vary with tech level
double turbineInletTempK = 1000; //TODO: make variable, add film cooling reqs for temps above 800
EngineDataPrefab combustorPrefab = propConfig.CalcDataAtPresAndTemp(preburnerPressureMPa, turbineInletTempK, false);
}
public EngineDataPrefab CalcData(double inputChamberPres)
{
EngineDataPrefab prefab = new EngineDataPrefab();
prefab.OFRatio = oFRatio;
prefab.chamberPresMPa = inputChamberPres;
prefab.chamberTempK = 0;
prefab.nozzleTempK = 0;
prefab.nozzlePresMPa = 0;
prefab.nozzleMWgMol = 0;
prefab.nozzleGamma = 0;
prefab.nozzleMach = 0;
if (inputChamberPres < minChamPres)
{
Debug.LogError("[ProcEngines] Error: chamber pressure of " + inputChamberPres + " is below min pressure of " + minChamPres + " for " + mixtureName + " at O//F " + oFRatio);
return(prefab);
}
if (inputChamberPres > maxChamPres)
{
Debug.LogError("[ProcEngines] Error: chamber pressure of " + inputChamberPres + " is below min pressure of " + maxChamPres + " for " + mixtureName + " at O//F " + oFRatio);
return(prefab);
}
for (int i = 1; i < chamberPresMPaData.Length; ++i)
{
double chamPres2 = chamberPresMPaData[i];
if (chamPres2 < inputChamberPres)
{
continue;
}
double chamPres1 = chamberPresMPaData[i - 1];
double indexFactor = inputChamberPres - chamPres1;
indexFactor /= (chamPres2 - chamPres1); //this gives us a pseudo-index factor that can be used to calculate properties between the input data
prefab.chamberTempK = (chamberTempKData[i] - chamberTempKData[i - 1]) * indexFactor + chamberTempKData[i - 1];
prefab.nozzleTempK = (nozzleTempKData[i] - nozzleTempKData[i - 1]) * indexFactor + nozzleTempKData[i - 1];
prefab.nozzlePresMPa = (nozzlePresMPaData[i] - nozzlePresMPaData[i - 1]) * indexFactor + nozzlePresMPaData[i - 1];
prefab.nozzleMWgMol = (nozzleMolWeightgMolData[i] - nozzleMolWeightgMolData[i - 1]) * indexFactor + nozzleMolWeightgMolData[i - 1];
prefab.nozzleGamma = (nozzleGammaData[i] - nozzleGammaData[i - 1]) * indexFactor + nozzleGammaData[i - 1];
prefab.nozzleMach = (nozzleMachData[i] - nozzleMachData[i - 1]) * indexFactor + nozzleMachData[i - 1];
break;
}
if (prefab.chamberTempK <= 0)
{
Debug.LogError("[ProcEngines] Error in data tables, could not solve");
}
return(prefab);
}
public static EngineDataPrefab operator -(EngineDataPrefab a, EngineDataPrefab b)
{
EngineDataPrefab prefab = new EngineDataPrefab();
prefab.OFRatio = a.OFRatio - b.OFRatio;
prefab.chamberPresMPa = a.chamberPresMPa - b.chamberPresMPa;
prefab.chamberTempK = a.chamberTempK - b.chamberTempK;
prefab.nozzlePresMPa = a.nozzlePresMPa - b.nozzlePresMPa;
prefab.nozzleTempK = a.nozzleTempK - b.nozzleTempK;
prefab.nozzleMWgMol = a.nozzleMWgMol - b.nozzleMWgMol;
prefab.nozzleGamma = a.nozzleGamma - b.nozzleGamma;
prefab.nozzleMach = a.nozzleMach - b.nozzleMach;
prefab.frozenAreaRatio = a.frozenAreaRatio - b.frozenAreaRatio;
return(prefab);
}
public static EngineDataPrefab operator *(EngineDataPrefab a, double b)
{
EngineDataPrefab prefab = new EngineDataPrefab();
prefab.OFRatio = a.OFRatio * b;
prefab.chamberPresMPa = a.chamberPresMPa * b;
prefab.chamberTempK = a.chamberTempK * b;
prefab.nozzlePresMPa = a.nozzlePresMPa * b;
prefab.nozzleTempK = a.nozzleTempK * b;
prefab.nozzleMWgMol = a.nozzleMWgMol * b;
prefab.nozzleGamma = a.nozzleGamma * b;
prefab.nozzleMach = a.nozzleMach * b;
prefab.frozenAreaRatio = a.frozenAreaRatio * b;
return(prefab);
}
public EngineDataPrefab CalcPrefabData(double oFRatio, double chamberPres, int indexLow)
{
double oF2 = mixtureOFRatios[indexLow + 1];
double oF1 = mixtureOFRatios[indexLow];
EngineDataPrefab prefab1, prefab2;
prefab1 = mixtureData[indexLow].CalcData(chamberPres);
prefab2 = mixtureData[indexLow + 1].CalcData(chamberPres);
double indexFactor = oFRatio - oF1;
indexFactor /= (oF2 - oF1); //this gives us a pseudo-index factor that can be used to calculate properties between the input data
EngineDataPrefab results = (prefab2 - prefab1) * indexFactor + prefab1;
return(results);
}
public static EngineDataPrefab operator +(EngineDataPrefab a, EngineDataPrefab b)
{
EngineDataPrefab prefab = new EngineDataPrefab();
prefab.OFRatio = a.OFRatio + b.OFRatio;
prefab.chamberPresMPa = a.chamberPresMPa + b.chamberPresMPa;
prefab.chamberTempK = a.chamberTempK + b.chamberTempK;
prefab.nozzlePresMPa = a.nozzlePresMPa + b.nozzlePresMPa;
prefab.nozzleTempK = a.nozzleTempK + b.nozzleTempK;
prefab.nozzleMWgMol = a.nozzleMWgMol + b.nozzleMWgMol;
prefab.nozzleGamma = a.nozzleGamma + b.nozzleGamma;
prefab.nozzleMach = a.nozzleMach + b.nozzleMach;
prefab.chamberCp = a.chamberCp + b.chamberCp;
prefab.nozzleCp = a.nozzleCp + b.nozzleCp;
prefab.frozenAreaRatio = a.frozenAreaRatio + b.frozenAreaRatio;
return(prefab);
}
double turbinePresRatio = 2; //keep it low for staged combustion
void CalculateChamberParameters()
{
//Calc geometry
nozzleArea = nozzleDiameter * nozzleDiameter * 0.25 * Math.PI;
throatArea = nozzleArea * areaRatio;
//Generate engine prefab for this OF ratio and cham pres
enginePrefab = propConfig.CalcPrefabData(chamberOFRatio, chamberPresMPa);
//Calc mass flow for a choked nozzle
massFlowChamber = (enginePrefab.nozzleGamma + 1) / (enginePrefab.nozzleGamma - 1);
massFlowChamber = Math.Pow(2 / (enginePrefab.nozzleGamma + 1), massFlowChamber);
massFlowChamber *= enginePrefab.nozzleGamma * enginePrefab.nozzleMWgMol;
massFlowChamber /= (GAS_CONSTANT * enginePrefab.chamberTempK);
massFlowChamber = Math.Sqrt(massFlowChamber);
massFlowChamber *= enginePrefab.chamberPresMPa * throatArea;
massFlowChamber *= 1000; //convert from 1000 t/s (due to MPa) to t/s
double effectiveFrozenAreaRatio = NozzleAeroUtils.AreaRatioFromMach(enginePrefab.nozzleMach, enginePrefab.nozzleGamma);
double effectiveExitAreaRatio = areaRatio * enginePrefab.frozenAreaRatio / effectiveFrozenAreaRatio;
double exitMach = NozzleAeroUtils.MachFromAreaRatio(effectiveExitAreaRatio, enginePrefab.nozzleGamma);
double isentropicRatio = 0.5 * (enginePrefab.nozzleGamma - 1);
isentropicRatio = (1 + isentropicRatio * enginePrefab.nozzleMach * enginePrefab.nozzleMach) / (1 + isentropicRatio * exitMach * exitMach);
double exitTemp = isentropicRatio * enginePrefab.nozzleTempK;
exitPressureMPa = Math.Pow(isentropicRatio, enginePrefab.nozzleGamma / (enginePrefab.nozzleGamma - 1)) * enginePrefab.nozzlePresMPa;
double exitSonicVelocity = Math.Sqrt(enginePrefab.nozzleGamma * GAS_CONSTANT / enginePrefab.nozzleMWgMol * exitTemp);
exhaustVelocityOpt = exitSonicVelocity * exitMach;
thrustChamberVac = exhaustVelocityOpt * massFlowChamber + exitPressureMPa * nozzleArea * 1000;
thrustChamberSL = exhaustVelocityOpt * massFlowChamber + (exitPressureMPa - 0.1013) * nozzleArea * 1000;
massFlowChamberFuel = massFlowChamber / (chamberOFRatio + 1);
massFlowChamberOx = massFlowChamberFuel * chamberOFRatio;
}
