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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