Page 195 - 48Fundamentals of Compressible Fluid Mechanics

9.7. WORKING CONDITIONS 157
Fanno Flow
M as a function of M
1 2
1
4fL
0.9 ¾¾ = 0.1
D
= 1.0
0.8
= 10.0
= 100.0
0.7
Entrace Mach number 0.6

0.5

0.4

0.3

0.2

0.1
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Exit Mach number
Tue Oct 19 09:56:15 2004

for different
Fig. 9.9: % as a function

, below the maximum critical length, the entrance super-
sonic entrance has three different regimes which depends on the back pressure.
For a given WYXaZ [
One, shockless flow, shock at the entrance, and shock at the exit. The below the
maximum critical length is mathematically

I F
F I
I

W`XaZ [

F
F
" F
I

above the maximum critical length no supersonic flow cannot be
over whole tube and at some point a shock will occur and the flow becomes sub-
For cases W`XaZ [
15
sonic flow .
15 See more on the discussion about changing the length of the tube.