AIR-COMPRESSORS
By
Dr. S. SABOOR
D.M.E., B-Tech (Gold Medalist)., M-Tech (R&A/C)., PhD (Mech.)., M ASHRAE., M ASME
Senior Assistant Professor
E-Mail: saboor.s@vit.ac.in
Department of Thermal and Energy Engineering
School of Mechanical Engineering
VIT University, Vellore, TN, India.
1
CLASSIFICATION OF COMPRESSORS
1.) POSITIVE DISPLACEMENT TYPE COMPRESSORS
• RECIPROCATING
• ROTARY
SCREW
RECIPROCATING
SCREW
SCROLL
SCROLL
LOBE
VANE
LOBE
SINGLE STATIONARY BLADE
A.) SINGLE STATIONARY BLADE
ROTATING BLADE
B.) ROTATING BLADE TYPE
2.) NON POSITIVE DISPLACEMENT TYPE COMPRESSORS OR NON POSITIVE TYPE COMPRESSORS
• CENTRIFUGAL
• AXIAL
AXIAL
CENTRIFUGAL
n-1/n
Sine P1V1n =P2V2n
n-1/n
n-1/n
Single acting
Double acting
Block diagram of reciprocating compressor
It is a piston and cylinder
device with (automatic)
spring controlled inlet and
exhaust valves
There is a clearance
between the piston crown
and the top of the
cylinder.
n-1/n
PROBLEM ON FREE AIR DELIVERY
a
(V1-V4)
(V1-V4)
(V1-V4)
(V1-V4)
Why multistage compressor?
High
temp rise leads into limitation for the maximum achievable pressure
rise.
Discharge temperature shall not exceed 150ºC and should not exceed 1350C
for hydrogen rich services
A multistage centrifugal compressor compresses air to the required
pressure in multiple stages.
Intercoolers are used in between each stage to removes heat and decrease
the temperature of gas so that gas could be compressed to higher pressure
without much rise in temperature
CONDITION FOR MAXIMUM EFFICIENCY AND MINIMUM WORK OF MULTISTAGE COMPRESSOR
PROBLEMS
PROBLEMS