the great squeeze

7/31/2019 The Great Squeeze

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The Great Squeeze

Team 5:

Freddie

Fahmi

Jian Ping

Alvin

Raj


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Content

Compressors - Alvin

Axial Compressor Centrifugal Compressor

Fan Trim Balance Freddie

Compressor Stall & Surge Freddie

Bleed Band/Bleed Valve Fahmi

Variable Inlet Guide Vanes (VIGVs) Raj

Compressor Ratio Jian Ping

Conclusion


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CompressorThere are many different types of compressors, but we will focus on the 2 main ones:

Reciprocation compressors

Scroll compressor

Axial-flow compressor Centrifugal compressors


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Compressor Axial-flow compressor

Axial flow compressors uses arrays of airfoil shaped blades to compress air (working

fluid).

Rotors are moving components and stators are fixed components.

Airflow for axial compressors are parallel to the axis of rotation.

Purpose of a compressor is to gradually raise the pressure through its stages and reducethe volume of air flowin throu h it.

Rotor Stators


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Compressor Centrifugal compressor

Centrifugal compressors has 3 main parts: The rotating impeller, the diffuser and the

compressor-manifold section.

A centrifugal compressor forces air upwards into the diffuser (the narrowing chamber)

and channels it to the combustion chamber.

The diffuser slows down the air velocity and increases pressure.

Centrifugal force is force that acts outwards of a spinning object thus the air exits

upwards from the impeller.


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Fan trim balance

Fan trim balance is balancing of the fan assembly

to reduce unwanted, unproductive,

cyclic oscillation of the fan assembly about its

rotational axis.

Fan trim balance is necessary to reduce vibration

and noise induced stress on passengers and crew,less damages to airframe, increasing the efficiency

of the engine.


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Measuring vibration

Displacement -

Measures physical

change of position.

Velocity - Measures therate

of change of

displacement with time.

Acceleration -

Measures the

rate of change of

velocity with time.


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Compressor stall

Compressor stall is a local disruption of airflow within the

compressor which continues to provide compressed air

but with reduced effectiveness.

Rotational stall arises when a small proportion of

aerofoils experience aerofoil stall disrupting the local

airflow without destabilising the compressor.

Compressor stall can be mild and self corrected after 2

pulsations, or continued to become the more serious

compressor surge.


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Compressor surge

It is a complete breakdown in compression resulting in a

reversal of flow and the violent expulsion of previously

compressed air out through the engine intake.

The compressor's is unable to continue working against thealready-compressed air behind it.

Compressor surge is when the stall propagates from the small

proportion of aerofoil stall to include the entire compressor.

The compressor surge will cause multiple stall spread to the

entire compressor and the compressor is destabilised


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Causes of compressor stall

Compressor stall can be attributed to damage to the

compressor by:

Foreign object damage by debris ingestion

Worn or contaminated compressor components

Operation out of design specifications

Turbulent or distorted / disrupted airflow to the

engine inlet reducing the axial velocity


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Bleed Band

Bleed Bands are simply a band drawn tight around asection of the Compressor housing or case, covering

a series of openings or ports in the case.

They are commonly used on smaller engines, often

between the axial part of a Compound Compressor,

and the centrifugal section.


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Bleed Valve

They are essentially a set of floating

poppet style bleed valves positioned

circumferentially around the compressor

case,

often at two stages of the compressor (e.g.

8th and 13th Stage Bleed).


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Variable Inlet Guide Vanes(VIGVs)

To ensure a compressor

surge margin and also

guide the air through the

compressor.


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VIGV system (Small engine)

At low mass airflow Ms, slightly high N1 speeds. During aStartup or Acceleration .

VIGVs are closed to direct the inlet air in the direction

of Rotor rotation, while at higher Ms and N1 speeds, the VIGVs

are open allowing unobstructed airflow to the engine.

Both inlet has air speed (Ms) compressor speed (N1) are

constantly changing, must to vary the AOA.

Controlled by the (FCU) monitors N1 speed, Inlet Air Pressure(Cip),

and Compressor Inlet Temperature (Tt2).

ar a e n e u e anes(VIGVs))


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Compressor Ratio

Stage 1 = 14.7x1.2

= 17.64

Stage 2 = 17.64 x 1.2

= 21.168

Stage 3 = 21.168x1.2

=25.4016Stage 4 = 25.4016x1.2

=30.48192

Compressor ratio = final pressure/initialpressure

= 75.84877/14.7

= 5.159780 : 1

Stage 5 = 30.48192x1.2

=36.578304

Stage 6 = 36.578304x1.2

=43.8939648

Stage 7 = 43.8939648x1.2

= 52.67275776Stage 8 = 52.67275776x1.2

=63.207309312

Stage 9 = 63.207309312x1.2

=75.8487711744

Final pressure = 75.85


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ConclusionIndividuals life Turbine Engine

Compressor Operations

Ability to absorb pressure

in life

Cool temper VIGV

Ability to absorb high

pressure

Withstand stressful

situation

Making use of suitable

materials

Techniques of pressure

relief

Activities sleeping,

exercising, eating, etc.

Bleed Bland/Bleed Valve

Balanced life-style Balancing work & studies Fan Trim

Result of an unbalanced

lifestyle

Health Issues Compressor Stall & Surge

Management of daily

routine

Time Management Routing Maintenance

Efficiency Achieve a desired result Compression Ratio

the great squeeze

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