finite element analysis on screw compressor

8/2/2019 Finite Element Analysis on Screw Compressor

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DEPARTMENT OF MECHANICAL ENGINEERING

PROJECT REVIEW


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FINITE ELEMENT ANALYSIS ON

SCREW COMPRESSORPROJECT DONE BY :

1.DINESH A.J 3440810171

2.GIKKU DEVASSIA 34408101943.HIFNI NAZAR N 34408102084.JAINJO C THOMAS 34408102165.JAMSHEER K.P. 3440810218

GUIDED BY :

PROF. S .RAJA


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INTRODUCTION

Screw compressors are same as piston

compressors in the principle of the rise ofthe air pressure, one rotor acts as a pistonand other forms as cylinder in screw

compressor and both belong to positivedisplacement compressors.


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TYPESOil flooded compressors Oil Free compressors

Cools the compressor

Lubricates the bearings andgears

Seals the air leakage paths,improves efficiency

Air does not contact thelubricating oil and the rotorsdont contact directly andremain space between eachother.

Male rotors drive female

rotors through timing gearand it keeps the spacebetween rotors.


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SCREW COMPRESSOR DESIGNDesign of screws

Selection of bearingsSelection of seals


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THEORETICAL APPROACH TO

CALCULATE THE CLEARANCES

Sealing line length

Blowhole area

Radial clearance

Interlopes clearanceAxial clearance


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OPERATING AXIAL

CLEARANCE

OPERATING INTER-LOBE

CLEARANCE

It is the function of coldclearance set during theassembly, internal

clearance of the axialbearing, thermalexpansion of the shafthousing between axialbearing and discharge endface

It is the function of coldclearance set during theassembly, internalclearance of the radialbearing, thermalexpansion of the rotorthermal expansion ofhousing bore, torsional

deformation of rotors andoperating backlash of thegears.


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OPERATING RADIALCLEARANCE It is function of cold

clearance set duringthe assembly;internal clearance ofthe radial bearingthermal expansion

of the rotor andhousing bore.


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FINITE ELEMENT METHOD Finite element method is the most popular numeric

technique to solve continuum-engineering problem

It occupies predominant role and have a significantimpact in the industry

The actual structure is replaced by a conceptualmodel, which we can call as finite element method.

Based on the principles of discretization and numericapproximation to solve scientific and engineeringproblem, which are fact of the life


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GENERAL PROCEDURE OF THE

FINITE ELEMENT METHOD Define Physical Proplem

FEM(Generate nodes,Elemenets,boundry

condition,material properties,loads,date files) FEM(Generate nodes,Elements,Matrices, Compute

nodal value and Derivatives,Store Result)

Analyses Result ( Display curves, Deformedshapes)


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DISCRETIZATION The essence o the finite element method is to divide a

continuum, that is, Problem domain, in to quasi-disjoint non-overlapping elements. This is achieved byreplacing the continuum by a set of key.

Points called nodes, which then connected properlyproduces the elements. the collection of nodes andelement shapes and types are available

As a general rule, the larger the number of nodes andelements, the more accurate the finite elementsolution


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SELECT THE SOLUTION

APPROXIMATION

The variation of unknown (called field variable) in theproblem approximated within each element bypolynomial

The field variable may be a scalar or vector(Displacement)

The degree of polynomial depends on the number of

nodes per element, the number of unknown at eachnode.


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SOLVE FOR THE UNKNOWN AT THE

NODES The globe system of algebric equation is solved by

gauss elimination method to provide the value of thefield variable at the nodes of the finite element mesh.

Values of the field variable and their derivatives at thenodes form the complete finite element solution of theoriginal continuum problem before discretizationvalues at other point in side continuum other than thenodes are possible to obtain although It is notcustomarily done


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INTERPRET THE RESULTThe final step is to analyze the solution and

result obtained from the previous step to

make design decisions


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SPECIFICATION OF THE COMPRESSOR

SI NO PARAMETER UNIT SPECIFICATION

1 FAD CFM 230

2 SHAFT POWER KW 30

3 TEMP DIFF OF AIR C 25

4 TEMP DIFF OF OIL C 40


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PHYSICAL PROPERTIES OF EN-8

SI NO PARAMETERS SYMPOL VALUE

1 Density g/cc 7.85

2 Hardness Mpa 510

3 Tensile strength Mpa 245

4 Yield strength Mpa 530

The rotor has been manufactured from Extrusion steel rod.


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Pro-E Model


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finite element analysis on screw compressor

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