International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 7, July 217, pp. 118 133, Article ID: IJMET_8_7_111 Available online at http://www.iaeme.com/ijmet/issues.asp?jtype=ijmet&vtype=8&itype=7 ISSN Print: 976-634 and ISSN Online: 976-6359 IAEME Publication Scopus Indexed OPTIMIZATION OF RATIO AND PRE TWIST ANGLE FOR DESIGN OF GAS TURBINE BLADE WITH RESPECT TO THE STRUCTURAL CRITERIA Kalapala Prasad Asst. Professor, Department Mechanical Engineering, UCEK, JNTU Kakinada, A.P, India B. Anjaneya Prasad Professor & Director of Evaluation, Mechanical Engineering, JNTUH College of Engineering Hyderabad (Autonomous), India M. Anandarao Principal M.L.R.I.T, Hyderabad, India ABSTRACT The present paper deals mainly about static structural analysis of gas turbine blades. The research was already done on blade of aerofoil section whereas my analysis is on twisted aerofoil blade. The greatest significance of present research is that it describes the suitable material for the design of blade to withstand maximum stresses. The model design is created using CATIA V5 software. Model analysis is done by using Ansys 15.. Design is manufactured and structural analysis is done in order to investigate the effect of Tapper Ration (both height and depth), Twisting blade angle and the material. Analysis of static structural characteristics like stress and deformation is done. The pre twist angles are,15,3,45 and 6 degrees and tapper ratio is 1, 1.5, 2., 2.5, 3., 3.5, 4., 4.5, and 5.. The materials used for the blades are Inconel-718, Ti6A14V and aluminum alloy 661. In brief our research is optimization of and pre-twist angle for design of gas turbine blade with respect to the structural criteria. With reference of analysis work of load deformation inconel-718 can withstand high stress value. Key words: Taper Ratio, Twisted Angle, Ansys, Catia, Structural Analysis, Breadth Ratio, Optimization. Cite this Article: Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao, Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To the Structural Criteria, 8(7), 217, pp. 118 133, 8(7), http://www.iaeme.com/ijmet/issues.asp?jtype=ijmet&vtype=8&itype=7 http://www.iaeme.com/ijmet/index.asp 118 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria INTRODUCTION Gas turbine is operated by means of number of processes taking place are compression of air, increase of gas temperature, expansion of temperature gases and finally the exhaust of gases. The turbine gets its input power by expanding the burnt gases through rings of rotating cantilever blades. At high speed operations the blades get deformed due to high pressure. To avoid repair cost we need to produce a reliable design. It is incorporated in the computer aided engineering in turbo machinery design process. LITERATURE REVIEW V.Veeraragavan [1] had done research on jet engine turbine blades of model C5 and concluded the molybdenum alloys have better temperature resistant capability. N.Vasudeva Rao [2] has done research on different types of the cooling technique which maintain the temperature of blades. He had used Inconel 718 and Inconel 155 and concluded Inconel 718 has the stress induce is lesser. V Raga-Deepu [3] studied on Gas turbine blades play a vital role in gas turbine power plant. They are designed to convert the heat energy to useful mechanical work. Krishnakanth [4] had done the structural and thermal analysis of gas turbine rotor blade using solid 95 element in ansys APDL. Previously the research work is done on Aerofoil gas turbine blades and its structural analysis. The greatest significance of this research work is that it is done on twisted aerofoil blade and analyzing its structure. THE PROPERTIES OF SELECTED MATERIALS s.no properties material Inconel 718 Ti6Al4V Aluminium alloy 661 1 Young s modulus,pa 2.8e11 1.2e11.71e11 2 Poisons ratio.29.36.33 3 Density,kg/m3 822 454 277 The above diagram represents the twisted aerofoil blade L is the length of blade B1, B2 are the breadths of the turbine blade D1, D2 are the depths of the turbine blade. Now considering the tapered ratios http://www.iaeme.com/ijmet/index.asp 119 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao CALCULATION OF ED BREADTH RATIO Considering B1=8 as a fixed value and finding out B2 value we consider different tapper values like 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 and different values of B2 is calculated. As a result the best tapper value is determined Table 1 S.No Bottom Breadth B 1 Tapper Value B 2 1 8 1. 8 2 8 1.5 53.3 3 8 2. 4 4 8 2.5 32 5 8 3. 26.7 6 8 3.5 22.8 7 8 4. 2 8 8 4.5 17.7 9 8 5. 16. ED DEPTH RATIO Considering D1 = 5 as a fixed value and finding out D2 value. We consider different tapper values like 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 and different values of D2 is calculated. As a result the best tapper value is determined S.No Bottom Depth D 1 Tapper Value D 2 1 5 1. 5 2 5 1.5 3.3 3 5 2. 2.5 4 5 2.5 2. 5 5 3. 1.67 6 5 3.5 1.43 7 5 4. 1.25 8 5 4.5 1.11 9 5 5. 1. TWISTED BLADE ANGLE We consider various blade angles like, 15, 3, 45, 6, and calculate the stress and deformations at following angles. Analyzing the least deformation the following particular angle is chosen. From the following observations we conclude the angle and tapper ratio for greater efficiencies of blade. These readings are tabulated for various materials like INCONEL-718, Ti64L4V and aluminum alloy. The stress values do not vary with respect to the twisted blade angle except the breadth and depth tapper ratio. http://www.iaeme.com/ijmet/index.asp 12 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria Table I Breadth Taper Ratio STRESS,MPA RATIO DEG 15 DEG 3 DEG 45 DEG 6 DEG 1 1 3666.9 378.9 3643 3319.7 31.2 2 1.5 489.3 4134.5 4268.3 3713.4 337.6 3 2 4418.1 4467.5 4527.7 412.3 3642.3 4 2.5 4685.5 4741.2 4749.8 4257.3 3863.3 5 3 4914.1 4968 4931.5 4464.2 452.9 6 3.5 599.7 5154.3 51.7 464.5 4211 7 4 5273.2 5329.6 5199 481.9 4358.4 8 4.5 5421.7 5478.8 5246.6 4942.4 4497.4 9 5 555.7 568.5 5373.7 565.5 463.5 stress 6 4 2 breadth taper deg 15 deg 3 deg 45 deg 6 deg Table II Breadth Taper Ratio of 15deg Twist STRESS IN MPA RATIO INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 1 378.9 321.4 232.8 2 1.5 4134.5 3576.2 2586.7 3 2 4467.5 3892.4 2794.2 4 2.5 4741.2 494.8 2962.8 5 3 4968 4294 317.2 6 3.5 5154.3 4453.9 3223.6 7 4 5329.6 466.7 3333.8 8 4.5 5478.8 4731.8 3427.7 9 5 568.5 4849 3518.9 breadth taper of 15 deg twist stress,mpa 6 4 2 http://www.iaeme.com/ijmet/index.asp 121 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao RATIO Table III Depth Taper Ratio STRESS,MPA DEG 15 DEG 3 DEG 45 DEG 6 DEG 1 1 3666.9 378.9 3643 3319.7 31.2 2 1.5 3529.8 3568.6 341.9 329 2912.3 3 2 3471.5 3641.9 3356.4 3158.1 2963.7 4 2.5 3447.2 3615.8 3333.6 3135.3 345.5 5 3 3439.4 368.1 3326.8 3127.6 3143.6 6 3.5 3442.4 361.3 3329.4 3167.2 3247 7 4 345.3 3617.8 3337.2 322.8 3349.9 8 4.5 3461.5 3629.7 3348.2 3275.6 3449.5 9 5 3474.4 3643 3361.1 333.2 3543.4 depth taper stress,mpa 4 3 2 1 deg 15 deg 3 deg 45 deg 6 deg Table IV Depth Taper Ratio of 15 DEG Twist STRESS IN MPA RATIO INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 1 378.9 321.4 232.8 2 1.5 3568.6 391.6 2234.7 3 2 3641.9 341.2 2198.1 4 2.5 3615.8 32.4 2182.9 5 3 368.1 314.3 2178.4 6 3.5 361.3 316.7 218.1 7 4 3617.8 323.8 2185.2 8 4.5 3629.7 333.8 2192.3 9 5 3643 345.3 22.6 http://www.iaeme.com/ijmet/index.asp 122 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria stress,mpa 4 3 2 1 depth taper of 15 deg twist Table V Breadth Taper Ratio 5 ANGLE IN DEGREES STRESS,MPA INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 555.6 4849 3518.9 2 15 568.5 4899.5 3545.7 3 3 5373.7 4694.4 3397.4 4 45 565.5 4425.3 322.6 5 6 463.5 422 291.8 breadth taper 5 stress,mpa 6 4 2 15 3 45 6 angle in degress Table VI Taper Ratio 1 STRESS,MPA ANGLE IN DEGREES INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 3666.9 321.4 232.8 2 15 378.9 3247.3 2347.4 3 3 3643 3696.1 2238.6 4 45 3319.7 294.8 21.5 5 6 31.2 2634.5 195 http://www.iaeme.com/ijmet/index.asp 123 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao 1 stress,mpa 4 3 2 1 15 3 45 6 angle in degrees Table VII Depth Taper Ratio 5 ANGLE IN DEGREES STRESS,MPA INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 3474.3 345.3 22.6 2 15 3643 3244.2 2326.9 3 3 3361.1 2944.7 2128.5 4 45 333.2 2778.9 257.9 5 6 3543.4 2956.7 2189.6 4 depth taper 5 stress,mpa 3 2 1 15 3 45 6 angle in degrees RATIO Table VIII Breadth Taper Ratio DEFORMATION,MM DEG 15 DEG 3 DEG 45 DEG 6 DEG 1 1 78.772 78.35 77.7 82.893 86.459 2 1.5 92.932 92.286 15.86 98.165 12.83 3 2 13.48 12.69 114.54 19.88 115.71 4 2.5 111.77 11.84 121.63 119.29 126.29 5 3 118.48 117.43 127.56 127.8 135.23 6 3.5 124.6 122.9 132.6 133.67 142.92 7 4 128.78 127.51 266.1 13933 149.63 8 4.5 132.82 131.46 136.94 144.25 155.67 9 5 136.32 134.88 14.72 148.57 16.8 http://www.iaeme.com/ijmet/index.asp 124 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria breadth taper deformation,mm 2 15 1 5 deg 15 deg 3 deg 45 deg 6 deg Table IX Breadth Taper Ratio of 15deg Twist DEFORMATION,MM RATIO INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 1 78.35 17.62 135.82 2 1.5 92.286 126.99 16.26 3 2 12.69 141.43 178.47 4 2.5 11.84 152.77 192.76 5 3 117.43 161.71 24.36 6 3.5 122.9 169.91 213.99 7 4 127.51 176.7 222.13 8 4.5 131.46 181.47 229.11 9 5 134.88 186.41 236.7 breadth taper of 15 deg twist deformation,mm 25 2 15 1 5 http://www.iaeme.com/ijmet/index.asp 125 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao RATIO Table X Depth Taper Ratio DEFORMATION,MM DEG 15 DEG 3 DEG 45 DEG 6 DEG 1 1 78.772 78.35 77.7 82.893 86.459 2 1.5 95.75 94.518 97.16 1.71 15.76 3 2 18.9 17.39 11.59 115.21 121.7 4 2.5 118.89 118.4 121.78 127.29 135.43 5 3 128.1 127.1 131.36 137.83 147.53 6 3.5 136.9 134.94 139.73 147.11 158.39 7 4 143.12 139.74 147.21 155.39 168.24 8 4.5 149.36 147.94 153.9 162.84 177.25 9 5 154.95 153.4 159.91 169.6 185.56 depth taper deformation,mm 2 15 1 5 deg 15 deg 3 deg 45 deg 6 deg RATIO Table XI Depth Taper Ratio of 15 Deg Twist INCONEL 718 DEFORMATION,MM TI6AL4V ALUMINIUM ALLOY 661 1 1 78.35 17.62 135.82 2 1.5 94.518 129.88 163.99 3 2 17.39 147.82 186.47 4 2.5 118.4 162.64 25.14 5 3 127.1 175.28 221.5 6 3.5 134.94 186.25 234.87 7 4 139.74 195.9 247.2 8 4.5 147.94 24.48 257.82 9 5 153.4 212.16 267.49 http://www.iaeme.com/ijmet/index.asp 126 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria depth taper of 15 deg twist deformation,mm 3 2 1 Table XII Breadth Taper Ratio 5 ANGLE IN DEGREES DEFORMATION,MM INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 136.32 186.4 236.8 2 15 134.88 184.44 232.68 3 3 14.72 192.42 242.75 4 45 148.57 23.13 256.27 5 6 16.8 219.82 277.35 breadth taper 5 deformation,mm 3 2 1 15 3 45 6 angle in degrees Table XIII Taper Ratio 1 ANGLE IN DEGREES DEFORMATION,MM INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 78.772 17.62 135.82 2 15 78.35 17.1 135.4 3 3 77.7 19.75 138.51 4 45 82.893 113.24 142.92 5 6 86.459 118.9 149.6 http://www.iaeme.com/ijmet/index.asp 127 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao 1 deformation,mm 2 1 15 3 45 6 angle in degrees Table XIV Depth Taper Ratio 5 ANGLE IN DEGREES DEFORMATION,MM INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 154.95 212.16 264.49 2 15 153.4 21.8 267.83 3 3 159.91 218.92 276.3 4 45 169.6 231.62 292.37 5 6 185.56 253.26 319.77 depth taper 5 deformation,mm 4 3 2 1 15 3 45 6 angle in degrees Table XV Breadth Taper Ratio NATURAL FREQUENCY,HZ RATIO DEG 15 DEG 3 DEG 45 DEG 6 DEG 1 1 11.6 11.61 123.51 96.581 92.514 2 1.5 113.87 114.37 122.2 19.68 15.68 3 2 123.48 123.95 129.67 119.42 115.42 4 2.5 131.7 131.52 135.94 127.15 123.15 5 3 137.28 137.71 141.19 133.49 129.54 6 3.5 142.47 142.88 145.68 138.83 134.95 7 4 146.89 147.27 169.69 143.41 139.63 8 4.5 15.7 151.6 149.56 147.39 143.69 9 5 154.3 154.37 152.95 15.89 147.35 http://www.iaeme.com/ijmet/index.asp 128 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria 2 breadth taper frequency,hz 15 1 5 deg 3 deg 15 deg 45 deg 6 deg Table XVI Breadth Taper Ratio of 15deg Twist NATURAL FREQUENCY,HZ RATIO INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 1 11.61 17.89 14.29 2 1.5 114.37 12143 117.45 3 2 123.95 131.6 127.32 4 2.5 131.52 139.65 135.12 5 3 137.71 146.23 141.51 6 3.5 142.88 151.74 146.85 7 4 147.27 156.44 151.4 8 4.5 151.6 16.37 155.32 9 5 154.37 164.2 161.81 2 breadth taper of 15 deg twist frequency,hz 15 1 5 http://www.iaeme.com/ijmet/index.asp 129 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao RATIO Table XVII Depth Taper Ratio NATURAL FREQUENCY,HZ DEG 15 DEG 3 DEG 45 DEG 6 DEG 1 1 11.6 11.61 123.51 96.581 92.514 2 1.5 15.92 16.4 14.45 11.93 98.249 3 2 19.74 11.24 18.4 16.8 12.61 4 2.5 112.89 113.35 111.64 19.47 16.14 5 3 115.54 115.97 114.38 112.32 19.11 6 3.5 117.83 118.23 116.74 114.79 111.67 7 4 119.83 119.71 118.8 116.95 113.91 8 4.5 121.59 121.95 12.63 118.87 115.91 9 5 123.17 123.51 122.27 12.6 117.71 depth taper frequency,hz 15 1 5 deg 15 deg 3 deg 45 deg 6 deg Table XVIII Depth Taper Ratio of 15 Deg Twist NATURAL FREQUENCY,HZ RATIO INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 1 11.61 17.89 14.29 2 1.5 16.4 112.95 19.24 3 2 11.24 116.96 113.15 4 2.5 113.35 12.26 116.37 5 3 115.97 123.6 119.9 6 3.5 118.23 125.47 121.44 7 4 119.71 127.58 123.49 8 4.5 121.95 129.45 125.31 9 5 123.51 131.12 126.93 http://www.iaeme.com/ijmet/index.asp 13 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria depth taper of 15 deg twist frequency,hz 15 1 5 ANGLE IN DEGREES Table XIX Taper Ratio 1 NATURAL FREQUENCY,HZ INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 11.1 17.89 14.29 2 15 11.61 18.49 14.87 3 3 123.51 16.7 12.56 4 45 96.581 13 99.618 5 6 92.541 98.578 95.379 1 frequency,hz 15 1 5 15 3 45 6 angle in degrees Table XX Breadth Taper Ratio 5 ANGLE IN DEGREES NATURAL FREQUENCY,HZ INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 154.3 164.2 161.81 2 15 154.37 164.4 159.1 3 3 152.95 162.81 157.6 4 45 15.89 16.52 155.43 5 6 147.35 156.62 151.71 http://www.iaeme.com/ijmet/index.asp 131 editor@iaeme.com
Kalapala Prasad, B. Anjaneya Prasad and M. Anandarao breadth taper 5 frequency,hz 17 16 15 14 13 15 3 45 6 angle in degrees Table XXI Depth Taper Ratio 5 ANGLE IN DEGREES NATURAL FREQUENCY,HZ INCONEL 718 TI6AL4V ALUMINIUM ALLOY 661 1 123.51 13.12 125.98 2 15 123.71 131.54 127.3 3 3 122.27 131.12 126.93 4 45 12.6 128.27 124.22 5 6 117.71 125.11 121.2 depth taper 5 frequency,hz 135 13 125 12 115 11 15 3 45 6 angle in degrees RESULTS AND DISCUSSIONS The turbine blade model is created by using CATIA V5 and it can be done the static structural analysis by using finite element package. This research involves the static structural analysis can be done to determine stress and deformation valves at different materials like Inconel-718, Ti 6A14V and aluminum alloy, at pre twist angles,15,,3,45 and 6 degrees for both (depth and breadth) tapper ration. With reference of analysis work the lower deformation for higher stress values is for INCONEL 718. The above diagram represents the twisted aerofoil blade L is the length of blade B 1, B 2 are the breadths of the turbine blade D 1, D 2 are the depths of the turbine blade. http://www.iaeme.com/ijmet/index.asp 132 editor@iaeme.com
Optimization of Taper Ratio and Pre Twist Angle For Design of Gas Turbine Blade with Respect To The Structural Criteria CONCLUSION The present research work deals with effect of stress and deformation values on breadth and depth as well as twisting the blade angle of G.T with tapper and without tapper. From this structural analysis we can investigate the effect of twisting the blade angle and the material used. The stress values are independent on twisting blade angle but dependent on breadth and depth tapper ratio. Inconel-718 have higher stress values then Ti6AL4V and aluminum alloy. Inconel-718 and aluminum alloy have deformation values almost be identical. In most of the cases Inconel-718 have low deformation values compared to other materials. From the research values Inconel-718 at Tapper ratio 5 and pre twist angle 15 degree is optimum choice for the design of gas turbine twisted aerofoil blade. ACKNOWLEDGEMENT I am very much thankful to great Acknowledge the Authors professor. B. Anjaneyaprasad (JNTUH), M. Anandarao on optimization of and pre twist angle for gas turbine blade with respect to the structural criteria to write up during my entire research and documentation. REFERENCES [1] V. Veeraragavan Effect Of Temperature Distribution In 1c4/6c5 Gas Turbine Blade Model Using Finite Element Analysis [2] R D V Prasad1, G Narasa Raju2, M S S Srinivasa Rao3, N Vasudeva Rao4 Steady State Thermal & Structural Analysis of Gas Turbine Blade Cooling System. [3] V.Raga Deepu, R.P.Kumar Ropichrla. Design And Coupled Field Analysis Of First Stage Gas Turbine Rotor Blades, International Journal of Mathematics And Engineering, Vol 13, No.2, Pages: 163-1612. [4] Krishnakanth P V (213), Structural and Thermal Analysis of Gas Turbine Blade by Using F.E.M, International Journal of Scientific Research Engineering & Technology (IJSRET), Vol. 2, No. 2, pp 6-65. [5] Aflobi, Investigation of turbine blade failure in a thermal power plant, Case Studies in Engineering Failure Analysis., 1(3), pp. 192-199, 213. [6] Cranch, Study of gas turbine blade material, International journal of Engineering Education and technology, 2(3), Nov 212 [7] Mohammed, Vibration analysis of gas turbine blade, International Journal of Advanced Research and Studies, 2(1,) Dec 212. [8] Morocco Ferioli, Design and coupled field analysis of first stage gas turbine rotor blades, International journal of Mathematics and Engineering, 13(2), Jan 211 [9] Povishera, Modal analysis of t gas turbine blade using ansys, International journal of Engineering Education and technology, 2(3), Nov 21. [1] Barhm Abdullah Mohamad and Abdelsalam Abdelhussien, Failure Analysis of Gas Turbine Blade Using Finite Element Analysis. International Journal of Mechanical Engineering and Technology, 7(3), 216, pp. 299 35. [11] Yash Krishna Menon and Dr. Jayakumar J. S., Numerical Simulation to Investigate Effect of Downstream Grooves on Film Cooling Effectiveness of Gas Turbine Blades. International Journal of Mechanical Engineering and Technology, 8(1), 217, pp. 34 316. [12] Gladicheva, The design and analysis of gas turbine blade, International Journal of Advanced Research and Studies, Vol 2, No.1, Dec 21. http://www.iaeme.com/ijmet/index.asp 133 editor@iaeme.com