REDUCTION OF NOISE IN COMP

RESSOR USING ACOUSTIC LINE

R

GUIDE:

MR.ARAVINDHAN

(ASSISTANT PROFESS0R)

RECBY:

SAMEER M (211613101033)

Final year

ACOUSTIC

DEFINITION:

It is the interdisciplinary science that deals with the study of all mechanical waves in gases,liquids, and solids such as vibration, sound, ultrasound, and infrasound.

NOISE FROM AIRCRAFT:

The noise originates from three main sources

Aerodynamics noise

Engine and other mechanical noise

Noise from aircraft system

NOISE INSIDE ENGINE COMPONENTS

Aircraft jet enigines are responsible for much of the aircraft noise, such as the buzzsaw noise generated when the tips of the fan blades reach supersonic speeds.

Noise also produced from exhaust. The high velocity jet leaving the back of the engine has an shear layer instability, ring vortex formation.Eventually leads to breakdown into turbulence.

PROJECT AREA: We are concentrating on reducing

the noise on compressor

AIM

Reducing the noise which was produced from compressor region using Acoustic liner.

ACOUSTIC LINER: It is a composite panel

Which has the ability to

Absorb or weakens the

Sound waves produced on

The compressor region and

Diffuser duct.

(stator and rotar blades)

It is placed on the

Nacelle cowling in the

Compressor region.

ACOUSTIC LINER REQUIRE

MENTSAcoustic Liners are fundamental in ensuring jet aircraft ar

e quiet, but they must also satisfy many other requirement

s:

Must be effective over a wide range of engine operating c

onditions and frequencies (reducing both tones and broad

band noise)

Must fit into the restricted space available (liner depth a

nd area)

Must be light to ensure that fuel burn is not penalised

Must be cost effective to buy their way onto the aircraft

Must be specified when many details of the airframe a

nd engine design have not been finalised, so the liner desi

gn must be robust

Must be integrated with other engine design requireme

nts

Must survive rain, ice, oil leaks, maintenance staff ...

Must satisfy manufacturability and maintainability requ

irements, for decades of in-service life in the exacting aer

o-engine environment

RECENT DEVELOPMENT OF USI

NG ACOUSTIC LINER

Recently there was huge demand for using Acoustic liner in Aircraft

various positions such as Engine Inlet and even in exhaust .

There was a recent development and testing of using acoustic liner in wing

inside casing to reduce airframe noise produced inside the wing section.

Application of Acoustic liner in fuselage section is developing right now in

order to act as a barear for preventing outside noise from entering

fuselage section.

•Material survey

•JT 3D-3=glass fibre reinforced epoxy

Composite in back plate, core material

Nomex honeycomb.

•CFM 56 -3= kevlar 49,aramid fibr

e reinforced composite in back pl

ate, thermoplastic elastomer core

material.

•V2500=carbon panel in back plate, d

ouble nomex honeycomb core with se

ptum

•A/c muffler=ceramic foams are used, p

orous material like metal rubber could b

e applied as facing sheet materials of h

oneycomb liners.

ACOUSTIC LINER:

Aircraft engine typically turbofans use acoustic Liner to damp engine noise.

Liners are applied on the internal walls of the engine nacelle in the intake and use

Helmholtz resonance principle for the dissipation of incident acoustic energy.

HOW TO MAKE AN ACOUSTIC LINER?

A porous top layer called Face Sheet.

A honeycomb structure providing internal partition

An impervious layer called Back Sheet or Back Skin.

Acoustic liners can be distinguished by their internal configuration on the

base of the number of honeycomb cell layer.

porous layer ( e.g. the septum and the face sheet) can be for example a

perforate plate, a wire mesh or a felt- metal.

The honey comb can be of alumunium or glass fiber and the cells size is selected

small enough to ensure an acoustic plane wave in the cell for the whole frequency

of interset.The face sheet and back-skin can be either metalic or in natural fiber or

synthetic fiber.

MATERIAL GOING TO USE

In acoustical liner, the material should be good enough for sound absorption

coefficient, noise reduction coefficient, acoustic impedance, and reflection

coeffecient.

LINER CONSTRUCTION & MATERIAL GOING TO USE.

we made an acoustic liner by using sandwach construction of composite materials.

A sandwhich consists of face material, core and the back sheet.

In which we are using a perforated alumunium face sheet .

In the core we are placing a nomex honey comb material.

In between the honeycomb and back sheet we are placing an septum material, which is an wire meshing of alumunium material.

In the back panel, we are using an natural fiber(JUTE) reinforced polymer material,in which natural fiber has more sound absorption than synthetic fiber.

MATERIAL SURVEY FROM JO

URNAL

Material comparison chart Frequency vs ISR

INSTRUMENTS REQUIRED

TO TEST ACOUSTIC LINER PANEL We are going to make use of jet compressor from the nozzle jet noise. We

are

going to set a rectangular tunnel like section.

So that we can compress the jet flow and make an artifical noise inside the

tunnel section instrument , without acoustic liner for different frequency we

are going to find sound inside the section.

After that we are going to use Acoustic liner in that section so that we

calculate the noise reduced in tunnel section by using microphone and

parameters to calculate like NR,TR , graph for SL VS Frequency can be

calculated.

LECTURER SURVEY

Evaluation of Ceramic Matrix Composite Technology for Aircraft Turbine Engine Applications

Michael C. Halbig1, Martha H. Jaskowiak2, James D. Kiser3, and Dongming Zhu4,NASA Glenn Research Center, Cleveland, OH 44135

Using Acoustic Liner for Fan Noise Reduction in Modern Turbofan Engines

Mohammadreza Azimi and Fathollah Ommi Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran

Noise pollution of air compressor and its noise reduction procedures by using an enclosure

Farhad Forouharmajd1,2, Parvin Nassiriz, Mohammad Reza Monazzam

APPLICATION STATUS OF COMPOSITE ACOUSTIC LINER INAERO-ENGINE Dongbing Geng , Kai Yi†, Chengyuan Shang Jian Yan , Yehong He

The role of absorptive silencer in reduction of low-frequency noise produced by a fan

Hossein Ali Yousefi, Farhad Forouharmajd, Leila Maghsudian1

Predicted sound absorption coefficients of absorber materials lined in a chamber

Farhad Forouharmajd1,2, Parvin Nassiri2, Mohammad Reza Monazzam2, Mohammadreza Yazdchi3

THANKYOU