public override string ToString()
{
StringBuilder sb = new StringBuilder();
sb.Append('{');
WriteName(sb, "V0");
sb.Append(V0.ToString() + ",");
WriteName(sb, "V1");
sb.Append(V1.ToString() + ",");
WriteName(sb, "V2");
sb.Append(V2.ToString() + ",");
WriteName(sb, "V3");
sb.Append(V3.ToString() + ",");
WriteName(sb, "V4");
sb.Append(V4.ToString() + ",");
WriteName(sb, "V5");
sb.Append(V5.ToString() + ",");
WriteName(sb, "V6");
sb.Append(V6.ToString() + ",");
WriteName(sb, "V7");
sb.Append(V7.ToString() + ",");
WriteName(sb, "V8");
sb.Append(V8.ToString() + ",");
WriteName(sb, "V9");
sb.Append(V9.ToString() + ",");
sb.Length--;
sb.Append('}');
return(sb.ToString());
}
public void CalculatePerformance(double pressure, double temperature, double velocity, double commandedThrottle)
{
if (Tt7 == 0)
{
mainThrottle = commandedThrottle;
}
else
{
mainThrottle = Math.Min(commandedThrottle * 1.5, 1.0);
abThrottle = Math.Max(commandedThrottle - 0.667, 0);
}
p0 = pressure * 1000; //freestream
t0 = temperature;
gamma_c = CalculateGamma(t0, 0);
Cp_c = CalculateCp(t0, 0);
Cv_c = Cp_c / gamma_c;
R_c = Cv_c * (gamma_c - 1);
M0 = velocity / Math.Sqrt(gamma_c * R_c * t0);
T1 = t0 * (1 + 0.5 * (gamma_c - 1) * M0 * M0); //inlet
P1 = p0 * Math.Pow(T1 / t0, gamma_c / (gamma_c - 1)) * TPR;
double prat3 = CPR;
double prat2 = FPR;
double k = FPR / CPR;
double p = Math.Pow(k, (gamma_c - 1) / eta_c / gamma_c);
for (int i = 0; i < 20; i++) //use iteration to calculate CPR
{
P2 = prat2 * P1;
P3 = prat3 * P1;
T2 = T1 * Math.Pow(prat2, (gamma_c - 1) / gamma_c / eta_c); //fan
T3 = T1 * Math.Pow(prat3, (gamma_c - 1) / gamma_c / eta_c); //compressor
T4 = (Tt4 - T3) * mainThrottle + T3; //burner
P4 = P3;
ff = Cp_c * (T4 - T3) / (Cp_c * (T4 - T3) + h_f); //fuel fraction
Cp_t = CalculateCp(T4, ff);
T5 = T4 * TTR; //turbine
double x = prat3;
prat3 = (1 + ff) * Cp_t * (T4 - T5) / T1 / Cp_c + 1 + BPR;
prat3 /= 1 + BPR * p;
prat3 = Math.Pow(prat3, eta_c * gamma_c / (gamma_c - 1));
prat2 = k * prat3;
if (Math.Abs(x - prat3) < 0.01)
{
break;
}
}
gamma_t = CalculateGamma(T5, ff);//gas parameters
Cp_t = CalculateCp(T5, ff);
Cv_t = Cp_t / gamma_t;
R_t = Cv_t * (gamma_t - 1);
P5 = P4 * Math.Pow((1 - 1 / eta_t * (1 - TTR)), gamma_t / (gamma_t - 1));
if (exhaustMixer && BPR > 0) //exhaust mixer
{
double Cp6 = (Cp_c * BPR + Cp_t) / (1 + BPR); //Cp of mixed flow -- kind of
T6 = T5 * Cp_t / Cp6 * (1 + BPR * Cp_c * T2 / Cp_t / T5) / (1 + BPR);
P6 = (P5 + BPR * 0.98 * P2) / (1 + BPR);
ff /= (1 + ff + BPR);
gamma_t = CalculateGamma(T6, ff);//gas parameters
Cp_t = CalculateCp(T6, ff);
Cv_t = Cp_t / gamma_t;
R_t = Cv_t * (gamma_t - 1);
}
else
{
T6 = T5;
P6 = P5;
}
if (Tt7 > 0)
{
T7 = (Tt7 - T6) * abThrottle * 3 + T6;//afterburner
}
else
{
T7 = T6;
}
P7 = P6; //rayleigh loss?
ff_ab = ff + Cp_t * (T7 - T6) / (Cp_t * (T7 - T6) + h_f); //fuel fraction
gamma_ab = CalculateGamma(T7, ff_ab); //gas parameters
Cp_ab = CalculateCp(T7, ff_ab);
Cv_ab = Cp_ab / gamma_ab;
R_ab = Cv_ab * (gamma_ab - 1);
//Nozzle code is from NASA
double P8 = P7;
double T8 = T7;
double p8, V8, A8;
double epr = P8 / P1;
double etr = T8 / T1;
double area8max = .75 * Math.Sqrt(etr) / epr;//ratio of nozzle area to ref area
A8 = area8max * Aref;
if (exhaustMixer && BPR > 0)
{
A8 *= (1 + BPR);
}
double eair = P8 * Math.Sqrt(gamma_ab / R_ab / T8) *
Math.Pow((.5 + .5 * gamma_ab), .5 * (1 + gamma_ab) / (1 - gamma_ab));//corrected mass flow per area
mdot = eair * A8;
double npr = P8 / p0;
double fac1 = (gamma_ab - 1.0) / gamma_ab;
V8 = Math.Sqrt(2.0 * R_c / fac1 * T8 * eta_n * (1.0 - Math.Pow(1.0 / npr, fac1))); //exit velocity
p8 = (npr <= 1.893) ? p0 : .52828 * P8;
thrust = V8 * mdot + (p8 - p0) * A8;
if (BPR > 0 && FPR > 1 && exhaustMixer == false)
{
fac1 = (gamma_c - 1) / gamma_c; //fan thrust from NASA
double snpr = P2 / p0;
double ues = Math.Sqrt(2.0 * R_c / fac1 * T2 * eta_n * (1.0 - Math.Pow(1.0 / snpr, fac1)));
double pfexit = (snpr <= 1.893) ? p0 : .52828 * P2; //exit pressure of fan
thrust += BPR * ues * mdot / (1 + ff_ab) + (pfexit - p0) * BPR * Aref;
}
double netthrust = thrust - mdot / (1 + ff_ab) * (1 + (exhaustMixer ? 0 : BPR)) * (velocity);//ram drag
Isp = thrust / (mdot * ff_ab * 9.81);
debugstring = "";
debugstring += "TTR:\t" + TTR.ToString("F3") + "\r\n";
debugstring += "CPR:\t" + prat3.ToString("F3") + "\r\n";
debugstring += "M0:\t" + M0.ToString("F3") + "\r\n";
debugstring += "p0: " + p0.ToString("F2") + "\tt0: " + t0.ToString("F2") + "\r\n";
debugstring += "P1: " + P1.ToString("F2") + "\tT1: " + T1.ToString("F2") + "\r\n";
debugstring += "P2: " + P2.ToString("F2") + "\tT2: " + T2.ToString("F2") + "\r\n";
debugstring += "P3: " + P3.ToString("F2") + "\tT3: " + T3.ToString("F2") + "\r\n";
debugstring += "P4: " + P4.ToString("F2") + "\tT4: " + T4.ToString("F2") + "\r\n";
debugstring += "P5: " + P5.ToString("F2") + "\tT5: " + T5.ToString("F2") + "\r\n";
debugstring += "P6: " + P6.ToString("F2") + "\tT6: " + T6.ToString("F2") + "\r\n";
debugstring += "P7: " + P7.ToString("F2") + "\tT7: " + T7.ToString("F2") + "\r\n";
debugstring += "EPR: " + epr.ToString("F2") + "\tETR: " + etr.ToString("F2") + "\r\n";
debugstring += "FF: " + ff.ToString("P") + "\t";
debugstring += "FF_AB: " + ff_ab.ToString("P") + "\r\n";
debugstring += "V8: " + V8.ToString("F2") + "\tA8: " + A8.ToString("F2") + "\r\n";
debugstring += "Thrust: " + (thrust / 1000).ToString("F1") + "\tmdot: " + mdot.ToString("F2") + "\r\n";
debugstring += "NetThrust: " + (netthrust / 1000).ToString("F1") + "\tSFC: " + (3600 / Isp).ToString("F3") + "\r\n";
//Debug.Log(debugstring);
}