Centrifugal flow - compressors in aircraft, Other Engineering

Centrifugal flow - Compressors in Aircraft:

The centrifugal impeller is rotated at high speed by the turbine and centrifugal action causes the air between the impeller vanes to accelerate radially outwards until it is thrown off at the tip into the diffuser. The radial movement of the air across the impeller, from eye to tip, causes a drop in air pressure at the eye and the faster the impeller is turning, the lower the pressure at the eye becomes. The low pressure existing at the eye of the revolving impeller induces a continuous flow of air through the engine intake and into the eye of the impeller. The air, in turn, is accelerated across the impeller and passed into the diffuser. The kinetic energy in the air is then converted to pressure energy ready to enter the combustion chamber. The action of the diffuser is illustrated in figure.

2263_Compressors1.png


The final volume and mass airflow delivered by the centrifugal compressor is dependent on:

a Pressure ratio
b Operating RPM
c Diameter of the impeller

NOTE: This is assuming a constant air density at the inlet of the compressor.

Pressure Ratio

The ratio of the inlet pressure to outlet pressure of the compressor is called pressure ratio. The higher the pressure of the air the more efficiently the thrust will be produced with a corresponding improvement to the fuel economy of the engine.
The maximum pressure ratio normally obtainable from a single stage centrifugal compressor is approximately 5:1 and from a two stage, approximately 8:1.Design of the more modern centrifugal compressors sees them approaching pressure ratios of 15:1.

Diameter of Impeller

A large impeller will deliver a greater mass of air than a small impeller, however a large diameter compressor leads to an increase in the frontal area of the engine causing excess drag forces on the aircraft.

332_Compressors2.png

Posted Date: 9/11/2012 8:42:44 AM | Location : United States







Related Discussions:- Centrifugal flow - compressors in aircraft, Assignment Help, Ask Question on Centrifugal flow - compressors in aircraft, Get Answer, Expert's Help, Centrifugal flow - compressors in aircraft Discussions

Write discussion on Centrifugal flow - compressors in aircraft
Your posts are moderated
Related Questions
PROPELLER TORQUE Propeller torque is produced by the aerodynamic drag on the blades when in motion. Propeller torque acts in the plane of rotation and opposes engine torque.

Double acting feathering system: To prevent excessive drag in the event of a propeller on engine failure, the double acting propeller as with the single acting propeller requir

NOR Gate: Figure shows a further example of a 2 input digital gate, again consisting of two NPN transistors, TR1 and TR2, in a different configuration. When input A and input

AIRCRAFT WEIGHING NOTE:     The C.A.A. will consider applications from aircraft constructors and operators to weigh certain types of aircraft on a sampling basis. (i.e. repre

Static electricity in aircraft: As mentioned earlier, the effects of static electricity are of considerable importance in the design of aircraft and aircraft equipment. An air

explain the fibre optic communication system with block diagram

Beta coefficients and standard deviation may be used as indicators of risk

sir how can I find the transfer function of control valve

how thermoelecteric thermometer is contructed and how it working