Page 169 - 48Fundamentals of Compressible Fluid Mechanics

8.7. EXAMPLES 131

The maximum flow rate is larger then the requested mass rate hence the flow is
not choked. It is note worthy to mention that since the isothermal model breaks
around the choking point, the flow rate is really some what different. It is more
appropriate to assume isothermal model hence our model is appropriate.
To solve this problem the flow rate has to accounted as

Now combining with equation (8.38) yields 1

#

From the table 8.1 or utilizing the program provides

#

(
#

The entrance Mach number obtained by
%

3'3 3!('( % % 3
% % 3 '3(

3'3 3((

3'3 3%

The pressure should be 0(*3(*%

0*% 0(*3(/%

%

3'3 3%

#
Example 8.2: 0(*3(/%
% % 3 0*33&
Note that table here above for this example are for
A flow of gas was considered for a distance of 0.5 [km] (500 [m]). A flow rate of
0.2 [kg/sec] is required. Due to safety concerns, the maximum pressure allowed
for the gas is only 10[bar]. Assume that the flow is isothermal and k=1.4, calculate
the required diameter of tube. The friction coefficient for the tube can be assumed