Question

Air flows in a pipe with a diameter, D=50 mm. The inlet conditions are: M1 = 3; total pressure,
P01 = 1000 kPa absolute; and temperature, T1 = 550 K. The friction coefficient is, f = 0.004. The exit Mach number decreases with the length of the pipe.

Write a Matlab code and plot the following while the exit Mach number to be changed from 2.5 to 0.99 with decrements of ?M=0.01:
a) L, length of the pipe that is going to give the desired exit Mach number,

b) the P2, pipe exit pressure, c) T2, pipe exit temperature,

d) P02, pipe exit total pressure.

Answer 1

Editable code:

M2=0.99:0.01:2.5;

L=13.501-(8.9275./M2.^2)+10.7137*log((1+0.2*M2.^2)./M2.^2);

plot(M2,L)

set(gca,'Xdir', 'reverse')

xlabel('M2 values')

ylabel('L (in m)values')

title('L Vs M2 plot')

Editable code:

M2=0.99:0.01:2.5;

P2=(81.66./M2.^2).*(sqrt(2.8./(1+0.2*M2.^2)));

plot(M2,P2)

set(gca,'Xdir', 'reverse')

xlabel('M2 values')

ylabel('P2 (in kPa) values')

title('P2 Vs M2 plot')

Editable code:

M2=0.99:0.01:2.5;

T2=1540./(1+0.2*M2.^2);

plot(M2,T2)

set(gca,'Xdir', 'reverse')

xlabel('M2 values')

ylabel('T2 (in K) values')

title('T2 Vs M2 plot')

Editable code:

M2=0.99:0.01:2.5;

P_02=(3000./M2).*(2.8./(1+0.2*M2.^2)).^-3;

plot(M2,P_02)

set(gca,'Xdir', 'reverse')

xlabel('M2 values')

ylabel('P_02 (in kPa) values')

title('P_02 Vs M2 plot')