Plotting performance vs inlet temp for jet engine and measuring performance as dh as shown. What am I doing wrong?
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close all
clear all
P1 = 101 ;%pressure in kpa
T1 = 298;%temperature in kelvin
n = 1.4;
Cp = 1.004;
Cv = 0.717;
R = 0.287 ;%gas constant in kJ/kg*k
v1 = R * T1/P1 ;%specific volume in m^3/kg
IsentConst1 = P1 * v1^n;
P2 = 28 * P1 ;%outlet compressor/inlet combuster pressure
T2 = ((P2 / P1)^((n-1)/n)) * (T1);
v2 = (R * T2) / P2;
Wc = Cp * (T2 - T1);
P3 = P2;
T3 = 2828 ;
v3 = R * T3 / P3;
IsentConst2 = P3 * v3^n;
Wt = Wc;
T4 = (-Wt / Cp) + T3;
v4 = ((P3 * v3^n)/(R * T4))^(1/(n-1));
P4 = R * T4 /v4;
IsentConst3 = P4 * v4^n;
u4 = Cv * T4;
h4 = u4 + P4 * v4;
P5 = P1;
v5 = (P4 *v4^n / P5)^(1/n);
T5 = P5 *v5 / R;
u5 = Cv * T5;
h5 = u5 + P5 * v5;
dh = (h5 - h4)*1000;%performance parameter
Ti = 298:0.001:900
for i = length(Ti)
result(i) = Cp * Ti(i)
end
Ti = 298:0.001:900
plot(Ti, result)
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回答(1 个)
Dyuman Joshi
2022-7-21
The for loop indexing is incorrect
close all
clear all
P1 = 101 ;%pressure in kpa
T1 = 298;%temperature in kelvin
n = 1.4;
Cp = 1.004;
Cv = 0.717;
R = 0.287 ;%gas constant in kJ/kg*k
v1 = R * T1/P1 ;%specific volume in m^3/kg
IsentConst1 = P1 * v1^n;
P2 = 28 * P1 ;%outlet compressor/inlet combuster pressure
T2 = ((P2 / P1)^((n-1)/n)) * (T1);
v2 = (R * T2) / P2;
Wc = Cp * (T2 - T1);
P3 = P2;
T3 = 2828 ;
v3 = R * T3 / P3;
IsentConst2 = P3 * v3^n;
Wt = Wc;
T4 = (-Wt / Cp) + T3;
v4 = ((P3 * v3^n)/(R * T4))^(1/(n-1));
P4 = R * T4 /v4;
IsentConst3 = P4 * v4^n;
u4 = Cv * T4;
h4 = u4 + P4 * v4;
P5 = P1;
v5 = (P4 *v4^n / P5)^(1/n);
T5 = P5 *v5 / R;
u5 = Cv * T5;
h5 = u5 + P5 * v5;
dh = (h5 - h4)*1000;%performance parameter
Ti = 298:0.001:900;
for i = 1:length(Ti)
result(i) = Cp*Ti(i);
end
plot(Ti, result)
xlim([250 1e3])
Alternatively you can use
plot(Ti,Cp*Ti)
instead of using a loop for a simple task.
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