International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
International Journal of Research and Innovation in Mechanical Engineering (IJRIME) FATIGUE FAILURE ANALYSIS OF STEAM TURBINE SHAFT USING FEM TECHNIQUE D.Jojappa1, K.Naresh babu2, K.krishnaveni3. 1 Research Scholar, Department of Mechanical Engineering, Chebrolu engineering college, Guntur, AP, India. 2 Assistant professor, Department of Mechanical Engineering, Chebrolu engineering college, Guntur, AP, India. 3 Associate professor, Department of Mechanical Engineering, Chebrolu engineering college, Guntur, AP, India.
Abstract The aim of the project is to locate best constrain location by evaluating steam turbine shaft with different materials. Initially data collection will be done to understand rectification methodology and approach. A 3D model of shaft will be prepared and exported into IGES (inertial graphical exchanging specifications) format to conduct further work in ANSYS. Structural analysis will be carried out on assembly to evaluate structural characteristics. Model analysis will be carried out on same to find natural frequency’s (for comparison with other results) Thermal analysis will be carried out on to find thermal characteristic. Comparison tables will be prepared according to the obtained results from Ansys; Conclusion will be made according to the obtained results. Key words: steam turbine, shaft, hollow shaft,fatigue failure analysis. *Corresponding Author: D.Jojappa, Research Scholar, Department of Mechanical Engineering, Chebrolu engineering collage, Guntur, AP, India. Email: darajojappa@gmail.com Year of publication: 2016 Review Type: peer reviewed Volume: III, Issue : I Citation: D.Jojappa, Research Scholar, "Fatigue Failure Analysis of Steam Turbine Shaft Using Fem Technique" International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET) (2016) 194-198
It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher power-to-weight ratio. Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about 80% of all electricity generation in the world is by use of steam turbines. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process. MODELS OF STEAM TURBINE SHAFT
INTRODUCTION OF STEAM TURBINE SHAFT Turbine shaft is one of the main machine element where high, intermediate and low pressure blades will be arranged with the support of journal bearing. It has to bear not only self, blades weight and also steam pressure, temperature and torque. Due to high fatigue lodes (continues cyclic load) caused by above conditions shaft becomes weaker; mainly selfweight is one of the big obstacle. If self-weight can be reduced fatigue life can be improved and also mechanical efficiency will be increased. Previous researcher’s has done the research on materials only, in this thesis work along with materials hollow shaft will be analysed.
The above image shows turbine shaft and bearings assembly
STEAM TURBINE: A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884.
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International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
The above image shows hallow shaft and bearings assembly
MATERIALS AND BOUNDARY CONDITIONS:
Equivalent stress value, it is also called as vonmisses stress which provides the average value of directional and principle stress using vonmisses theory of failure.
THERMAL ANALYSIS FOR SOLID MODEL-MATERIAL1
Weight= volume X density Low pressure blade set= 4695903 X 0.00000785 Kg/mm3 = 36.86 Intermediate pressure blade set= 2390470 X 0.00000785 Kg/ mm3 = 18.76 High pressure blade set= 2163510 X 0.00000785 Kg/mm3 = 16.98 Weight X newton’s = load Low pressure blade set Intermediate pressure blade set High pressure blade set
= 36.86 X 9.81=361.228 = 18.76 X 9.81=184.142 = 16.98 X 9.81=166.404
Load /area = pressure Shaft Area of each blade set Low pressure blade set Intermediate pressure blade set High pressure blade set
= = = =
268535mm 0.0013 0.000685 0.000619
Total heat flux
FATIGUE ANALYSIS FOR SOLID MODEL-MATERIAL 1
Material 1 AISI 4130 Steel (super alloy steel) Material 1 Material 2 Haynes Hastelloy C-276 alloy STRUCTURAL ANALYSIS FOR SOLID MODEL-MATERIAL 1
Safety factor range on object
STRUCTURAL ANALYSIS FOR HALLOW MODEL-MATERIAL 1
Total deformation
Equivalent stress
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International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
THERMAL ANALYSIS FOR HALLOW MODEL MATERIAL 1
Total heat flux
FATIGUE ANALYSIS FOR HALLOW MODEL- MATERIAL 1
The above image shows hallow shaft, bearings and center support bearing
STRUCTURAL ANALYSIS FOR HALLOW MODEL WITH CENTER BEARING-MATERIAL 2
Maximum life
STRUCTURAL ANALYSIS FOR HALLOW MODEL-MATERIAL 2
Equivalent stress value, it is also called as vonmisses stress which provides the average value of directional and principle stress using vonmisses theory of failure.
FATIGUE ANALYSIS FOR HALLOW MODEL WITH CENTER BEARING-MATERIAL 2
Total deformation
Safety factor range on object.
RESULT TABLES STRUCTURAL ANALYSIS Solid shaft
Equivalent stress
Hallow shaft
Materials
AISI 4130 Steel
C-276 alloy
AISI 4130 Steel
C-276 alloy
Total deformation
0.021188
0.02233
0.027235
0.026332
Stress
44.67
42.056
73.184
69.301
Strain
0.000221
0.000213
0.000437
0.000426
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International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET) FATIGUE ANALYSIS
THERMAL ANALYSIS Solid shaft Materials
Hallow shaft
AISI 4130 Steel
C-276 alloy
AISI 4130 Steel
C-276 alloy
Temperature
591.63
579.95
588.53
577.73
Heat flux
0.66966
0.42049
0.60857
0.38725
Thermal error
7.4585e6
1.7605e6
4.7633e6
9.8352e5
MODEL ANALYSIS Solid shaft
Hallow shaft
Materials
AISI 4130 Steel
C-276 alloy
AISI 4130 Steel
C-276 alloy
Total deformation HZ 1
144.92
143.39
168.41
166.42
Total deformation HZ 2
145.18
143.65
177.22
175.15
Total deformation HZ 3
418.62
413.79
372.42
368.31
Total deformation HZ 4
419.11
414.27
382.68
378.51
Total deformation HZ 5
709.51
695.61
475.99
470.09
Materials
C-276 alloy
LIFE
5e11
Damage
2.8291
CONCLUSION This thesis work deals with “FATIGUE FAILURE ANALYSIS OF STEAM TURBINE SHAFT USING FEM TECHNIQUE” to compare solid and hollow shafts; to suggest best material and suitable location for the center bearing. Structural, model, thermal and fatigue analysis is done on solid and hollow shafts along with bearings by varying materials; as per the analysis results hollow shaft is having little bit high stress and deformation but these are within the limit only while considering factor of safety. Bearing was installed near high pressure blades for additional support to use hollow shaft to reduce stress concentration; then above analysis was conducted to evaluate results. As per the analysis work results hollow shaft with center bearing and C-276 material will be the better option; using these conditionsshaft weight can be reduced up to 51kgs [^16%] which interns increases the mechanical efficiency. REFERENCE
FATIGUE ANALYSIS Solid shaft
Hallow shaft
Materials
AISI 4130 Steel
C-276 alloy
AISI 4130 Steel
C-276 alloy
LIFE
5e11
5e11
5e11
5e11
Damage
1.034
0.86538
3.7329
3.2395
HALLOW SHAFT WITH CENTER SUPPORT BEARING TABLE STRUCTURAL ANALYSIS Materials
C-276 alloy
Total deformation
0.22403
Stress
65.783
Strain
0.00041147 THERMAL ANALYSIS
Materials
C-276 alloy
Temperature
577.73
Heat flux
0.38723
Thermal error
9.8352e5 MODEL ANALYSIS
Materials
C-276 alloy
Total deformation HZ 1
372.95
Total deformation HZ 2
383.67
Total deformation HZ 3
953.67
Total deformation HZ 4
975.5
Total deformation HZ 5
1190.4
1.THERMAL STRESS ANALYSIS IN STEAM TURBINE ROTOR - A REVIEW by Ms. Mohini R. Kolhe1, Prof. A. D. Pachchhao2, Prof. H.G.Nagpure3. 2.Calculation of Thermal Stress and Fatigue Life of 1000 MW Steam Turbine Rotor by ShuangBian, Wenyao Li. 3.DESIGN AND ANALYSIS OF STEAM TURBINE ROTOR byM. Chandra Sekhar Reddy. 4.Residual Life Assessment of 60 MW Steam Turbine Rotor by K. Venkatesh*, P. VeeraRaju**, T. Jayananda Kumar** 5.TRANSIENT THERMAL ANALYSIS OF A STEAM TURBINE ROTOR by Shilpa P. Bhorkar, Dr. A.V. Vanalkar. 6.ZvonimirGuzović, BranimirMatijašević, TihomirMihalić “Characteristics Of Non- Stationary Thermal Stresses In The Low-Pressure Part Of The Rotor”15th International Research/Expert Conference TMT-2011,Prague,Czech Republic 12-18 September 2011. 7.Chunlin Zhang, Niansu Hu, Jianmei Wang, Qiping,chen,FengHe,Xiaoli “ Thermal Stress Analysis for Rotor of 600MW Steam Turbine”978-1-4244-48135/10/&25.00c/2010/IEEE. 8.G SukhvinderKaurBhatti, ShyamalaKumari, M L Neelapu, C Kedarinath, Dr. I N Niranjan Kumar” Transient State Stress Analysis On An Axial Flow Gas Turbine Blades And Disk Using Finite Element Procedure”. in Int. Conf. on HEAT TRANSFER, THERMAL ENGINEERING and ENVIRONMENT, Elounda, Greece, August 21-23, 2006 (pp323-330). 9.Deepak Dhar, A. M. Sharan.” Transient Stress Analysis and Fatigue Life Estimation of Turbine Blades” Journal of Vibration and Acoustics OCTOBER 2004, Vol. 126 Õ 495. 197
International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
10.Yong Li, Haoran Sun, YuhuoNie “Thermal Stress Analysis of 600MW Steam Turbine Rotor in Different Governing Modes” 978-1-422-4813-5 28-31-March2010 IEEE. 11.Sudheendra,V.S,SRamamurthKMurugesan”Transie nt,Thermal Analysis Of A Turbine Rotor”nal-ir.nal.res. in/8928 [7]Stuart R Holdsworth , EdoardoMazza&Arnd Jung” creep-fatigue damage developmentduring servicecycle thermo-mechanical fatigue test of 1CrMoV rotor steel”.
Author
D.Jojappa, Research Scholar, Department of Mechanical Engineering, Chebrolu engineering college, Guntur, AP, India.
K.Naresh babu, Assistant professor, Department of Mechanical Engineering, Chebrolu engineering college, Guntur, AP, India.
K.krishnaveni, Associate professor, Department of Mechanical Engineering, Chebrolu engineering college, Guntur, AP, India.
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