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How do you calculate the exit pressure of a nozzle?
How to calculate the ratio of the inlet-to-exit area of the nozzle
Why is the pressure ratio higher in a centrifugal compressor than an axial compressor?
There is a substantial increase in radius across the rotating blade rows of a centrifugal compressor, which is its primary distinguishing feature from the axial-flow compressors to get higher-pressure ratio. Who says the compression ratio on a centrifugal is higher than that of a screw compressor? Unless I`m not properly understanding the question, these facts are true: a screw (axial) compressor is a positive displacement machine, meaning everything that goes into it will come out. There are no losses for re-expansion etc. A centrifugal compressor`s impeller is designed with a given amount of `lift` which is basically the difference between suction and discharge pressures or compression ratio. Exceeding the designed lift capability results in a surge where the gas momentarily goes backwards through the impeller until the excess lift condition is corrected.
What is multistage reciprocating air compressor?
A multistage reciprocating air compressor is a compressor that compresses air in a number of stages. A multi-stage reciprocating air compressor may contain 2 or many cylinders, like low pressure, medium pressure and high pressure cylinders.
What are the function of valve in gas compressor?
a gas compressor is a device that increases pressure and reduces its volume
What is the concept of a multi spool drive in a gas turbine engine?
The area available for flow along the length of the Compressors are chosen so that it decreases along the length of the compressor, due to increase in density as air gets compressed across the stages. The cross sectional area distribution across the length of the compressor is chosen for design conditions. At lower rotational speeds of the compressor, the density increase is limited as the pressure rise is very less and flow accelerates in a converging duct resulting in higher velocities in the exit. This problem is severe resulting in high machine vibration and possible component failure for a compressor designed to produce pressure ratio of over 8:1 in a single shaft. Starting the compressor (and hence the engine) becomes a problem then. To overcome this, two shaft arrangement is used so that high pressure compressor rotates at higher speeds, thereby splitting the pressure rise between the spools to alleviate this issue. High pressure compressor and Low pressure compressor are aerodynamically coupled instead of mechanical coupling. Hence HPC drives the LPC by demanding mass flow or spilling it in to bypass. Posted by Kishore C on 16th May 2013
