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This type of compressor moves air by the use of rotating airfoils countered against static (nonmoving) airfoils. All airfoils are designed to move air "downward", or rearward in a jet engine. Since the purpose of a compressor is to compress, conditions can sometimes develop where the airfoils try to compress more than their design. Air begins to try to flow backwards to relieve the excess pressure. This backpressure is the same as an airplane wing increasing it's angle of attack (say by flying too slowly). The airfoil can't move enough air to maintain the pressure and the result is a stalled airfoil.
Modern jet engines will bleed air out the middle or back of such a compressor to prevent such stalls. Early jet engines had no such protections. A stalled compressor is actually easier to turn. This relieves the load on the turbine powering the whole thing and the engine overspeeds. The pilot sees a surge in the engine. If it overspeeds enough, catastrophic damage may occur to the turbine (it explodes). The compressor bleed lines help prevent such failure.
What else can I help you with?
Which type of rotary compressor used in gas turbine?
Rotating axial compressor.
Disadvantages of centrifugal compressor in gas turbine?
This relationship is the reason advances in turbines and axial compressors often find their way cutaway showing an axi-centrifugal compressor gas turbine.
Which is true when a radial compressor and an axial compressor with equal air flow and revolution are compared?
I don't understand the question. It would appear that you wish to compare a centrifugal compressor and an axial flow compressor operating at the same speed and delivering equal flow rates. What is the process fluid? What is the question? Is the "equal air flow" the mass flow rate? At what pressure differential would you like to consider these machines? What is it that you wish to compare? Is it weight, frontal area, mechanical efficiency, overall diameter, length, delivery temperature, input power or what?
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.
How many stages of compresion on a j79 gas turbine engine?
The J79 gas turbine engine features a single-stage fan and a nine-stage axial compressor, which together provide efficient air compression before combustion. This design allows the engine to achieve high thrust levels and operational efficiency. Overall, the engine has a total of nine stages of compression in the axial compressor.
Which type of rotary compressor used in gas turbine?
Rotating axial compressor.
Designing an axial fan for aircraft?
what do you mean? axial compressor (or) axial turbine? Their missions are different. Design for axial compressor or turbine, must be consider their performance. The performance is characterized by - pressure ratio, rotational speed and efficiency. The details of how to design axial fan, are very complex.
The frontal area of a centrifugal compressor as compared to axial flow compressor is larger or smaller?
the frontal area of a centrifugal compresor is more as compared to axial flow compressor for a given air flow. And for this reason axial compressors are being used in aircraft engines.
What is the cause of stall and surge in compressor?
stall and surge is caused when the flow in the compressor loses enthalpy and static energy so that it does not have enough power to approach the end of the axis; thus it remains in the annolus of the compressor and creates a stall cell. these cells gradually join each other and create stall zones which are rotating about the axis and are some times called rotating stall. if this stage does not get stopped, the stall cells will cover the whole annolus and will stop the fluid flow through the stages of the compressor and finally lead to surge. if surge happens, the compressor will be out of order.
How bleed valves can reduse compressor stall?
Bleed valves help reduce compressor stall by allowing a controlled release of air from the compressor during transient conditions, such as sudden throttle changes or rapid acceleration. By venting excess pressure and airflow, they help maintain optimal operating conditions and prevent the compressor from reaching stall conditions. This ensures smoother airflow and stabilizes the compressor's performance, ultimately enhancing engine efficiency and response.
What is the different between axial turbocharger and radial turbocharger?
An axial compressor uses many stages of "fans" with stators to compress air in the same direction as its original flow. An example of this is that of *most* turbojet engines' compressors. A radial (or centrifugal) compressor works at right angles to the airflow's original direction. An example of a radial compressor is the compressor on an automotive turbocharger.
What is the difference of an axial flow and centrifugal compressor?
The centrifugal flow compressor has a single or two stage unit using an impeller. The axial flow compressor is a multi-stage unit using alternate rows of rotating (rotor) blades and stationary (stator) vanes.
Is axial compressor multi stage?
Yes, an axial compressor can be designed as a multi-stage system. In a multi-stage axial compressor, multiple sets of rotating and stationary blades are arranged in series to incrementally increase the pressure of the air or gas as it passes through each stage. This design is commonly used in applications such as jet engines and gas turbines, where high efficiency and high pressure ratios are required. Each stage contributes to enhancing the overall performance of the compressor.
What is compressor stall about wing?
Compressor stall and a wing stall are different and unrelated. Compressor stall refers to the compressor section of a jet engine. The compressor section is comprised of several spinning round discs attached to a shaft that runs through the engine. Blades attached to each disc compress the intake air, which is later mixed with fuel and burned in the combustion chamber. If the intake flow of air is disrupted, compressor stall can occur, allowing high pressure gasses to move forward through the engine, making a loud banging noise. Compressor stalls are usually momentary and do not cause any damage or significant reduction in power. A wing stalls when the angle between the chord of the wing and the relative wind becomes excessive and the airflow over the top of the wing is disrupted. The disruption results in a sudden loss of lift and the aircraft will descend and may become uncontrollable.
What has the author Franklin K Moore written?
Franklin K. Moore has written: 'Research on rotating stall in axial flow compressors. Part IV. A preliminary study of three-dimensional rotating stall'
Why is the axial flow compressor better than the centrifugal compressor?
Higher peak volumetric efficiency. You don't have to turn the air at all, so you do not lose and energy in transforming it as you compress the air.
Disadvantages of centrifugal compressor in gas turbine?
This relationship is the reason advances in turbines and axial compressors often find their way cutaway showing an axi-centrifugal compressor gas turbine.
