Tutorial - Axial Compressors Notes | EduRev

: Tutorial - Axial Compressors Notes | EduRev

 Page 1


1
Lect-17
Page 2


1
Lect-17
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
2
Lect-17
In this lecture...
• Tutorial
– Axial compressors
Page 3


1
Lect-17
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
2
Lect-17
In this lecture...
• Tutorial
– Axial compressors
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
3
Lect-17
Problem # 1
Air at 1.0 bar and 288 K enters an axial flow 
compressor with an axial velocity of 150 m/s. There are 
no inlet guide vanes. The rotor stage has a tip diameter 
of 60 cm and a hub diameter of 50 cm and rotates at 
100rps. The air enters the rotor and leaves the stator in 
the axial direction with no change in velocity or radius. 
The air is turned through 30.2 degree as it passes 
through the rotor. Assume a stage pressure ratio of 1.2 
and overall pressure ratio of 6. Find a) the mass flow 
rate of air, b) the power required to drive the 
compressor, c) the degree of reaction at the mean 
diameter, d) the number of compressor stages required 
if the isentropic efficiency is 0.85.
Page 4


1
Lect-17
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
2
Lect-17
In this lecture...
• Tutorial
– Axial compressors
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
3
Lect-17
Problem # 1
Air at 1.0 bar and 288 K enters an axial flow 
compressor with an axial velocity of 150 m/s. There are 
no inlet guide vanes. The rotor stage has a tip diameter 
of 60 cm and a hub diameter of 50 cm and rotates at 
100rps. The air enters the rotor and leaves the stator in 
the axial direction with no change in velocity or radius. 
The air is turned through 30.2 degree as it passes 
through the rotor. Assume a stage pressure ratio of 1.2 
and overall pressure ratio of 6. Find a) the mass flow 
rate of air, b) the power required to drive the 
compressor, c) the degree of reaction at the mean 
diameter, d) the number of compressor stages required 
if the isentropic efficiency is 0.85.
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
4
Lect-17
Solution : Problem # 1
1
ß
a
C
1
V
U
2
C
U
2
V
2
ß
Page 5


1
Lect-17
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
2
Lect-17
In this lecture...
• Tutorial
– Axial compressors
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
3
Lect-17
Problem # 1
Air at 1.0 bar and 288 K enters an axial flow 
compressor with an axial velocity of 150 m/s. There are 
no inlet guide vanes. The rotor stage has a tip diameter 
of 60 cm and a hub diameter of 50 cm and rotates at 
100rps. The air enters the rotor and leaves the stator in 
the axial direction with no change in velocity or radius. 
The air is turned through 30.2 degree as it passes 
through the rotor. Assume a stage pressure ratio of 1.2 
and overall pressure ratio of 6. Find a) the mass flow 
rate of air, b) the power required to drive the 
compressor, c) the degree of reaction at the mean 
diameter, d) the number of compressor stages required 
if the isentropic efficiency is 0.85.
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
4
Lect-17
Solution : Problem # 1
1
ß
a
C
1
V
U
2
C
U
2
V
2
ß
Prof. Bhaskar Roy, Prof. A M Pradeep, Department of Aerospace, IIT Bombay
5
Lect-17
Solution: Problem # 1
° =
=
?
?
?
?
?
?
?
?
-
=
° = - =
° =
?
?
?
?
?
?
?
?
=
= ×
?
?
?
?
?
?
+
× = ×
?
?
?
?
?
?
+
× =
-
92 . 38
75 . 80
tan
tan
19 2 . 30 2 . 49
2 . 49 tan
/ 76 . 172 100
2
5 . 0 6 . 0
2
2
2
2
2
1
1
a
ß
a
ß
ß
p p
a
a
a
h t
C
C U
C
U
s m N
d d
U
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