Study of the Effects of Lacing Rods Location on Natural Frequencies in Last Stage Blades of a Steam Turbine

Subject Areas : Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering

مهدی نوذرپور ¹ (دانشجوی کارشناسی ارشد، دانشکده فنی و مهندسی، گروه مکانیک، دانشگاه آزاد اسلامی واحد اهواز)
عباس رهی ² (استادیار دانشکده مهندسی مکانیک و انرژی، پردیس فنی و مهندسی شهید عباسپور، دانشگاه شهید بهشتی)

Received: 2015-09-28 Accepted : 2015-09-28 Published : 2012-12-21

Keywords: Finite Element Method, Lacing rod, Turbine blades, resonance,

Abstract :

In this study, effects of lacing rods location on natural frequencies of last stage of a Steam Turbine Blades (STBs) have been investigated. STBs are critical and important elements in a turbine as well as power plants. One of the most important parameters in turbine blades is lacing rods location. In this paper, first, a three dimensional (3D) scan was used to produce the geometrical model of the blade. Then, last stage of a low pressure turbine have been produced and simulated by assembling of the one-blade model. There are two rows of lacing rods in the last stage of turbine. In this paper, effecting the lacing rods location on natural frequencies of system has been studied. According to the Campbell diagrams, the results showed there is no resonance in the last stage blades of the steam turbine for different locations of the lacing rods.

References:

[1] Stodola A., Steam and Gas Turbines, Vol. 1 and 2, McGraw-Hill, New York, 1927.

[2] Lamb H., Southwell R.V., The Vibration of a Spinning Disc, Process Royal Society of London, Vol. 99, pp. 272, 1922.

[3] Kroon R., Turbine Blade Vibration Due to Partial Admission, Transaction of ASME, InternationalJournal of Applied Mechanic, Vol. 7, pp. 161-165, 1940.

 

 

 

 

[4] Judge J., Pierre C., Mehmed O., Experimental Investigation of Mode Localization and Forced Response Amplitude Magnification for a Mistuned Bladed Disc, Journal of Engineering for GasTurbines and Power, Vol. 123, No. 4, pp. 940- 950, 2001.

[5] Periera J.C., Torres L.A.M., Rosa E., A Low Cycle Fatigue Analysis on a Steam Turbine Bladed Disk-case Study, 12th IFToMM World Congress, Besancon, Brazil, June 18-21, 2007.

[6] Moffatt S., He L., Blade Forced Response Prediction for Industrial Gas Turbines, International Gas Turbine & Aeroengine Congress & Exhibition, June 16-19, Atlanta, Georgia, USA, 2003.

[7] Christophe P., Jiang D., Finite-element-based Modal Reduction of a Rotating Blade With Large-amplitude-motion using Nonlinear Normal Modes, Department of Mechanical Engineering and Applied Mechanics, University of Michigan, 1997.

[8] Rao J.S., Turbomachine Blade Vibration, New age international publishers, 1987.

[9] وهابی، ح.، طراحی مکانیزم‏های صنعتی با استفاده از روش المان محدود در نرم‏افزار ANSYS، چاپ اول، تهران، انتشارات اندیشه‏سرا، 1390.

]10] بهزاد، م.، حسینی، س.م.ر.، ابراهیمی، ع.ر.، تحلیل ارتعاشات آزاد پره توربینهای گازی به منظور جلوگیری از خستگی دور بالا، سومین کنفرانس ملی نگهداری و تعمیرات، تهران، 1384.

]11] فتحی، م.، تاثیر ارتعاشات در شکست پره های توربین بخار، اولین کنفرانس ملی شبیه سازی سیستمهای مکانیکی، اهواز، دانشگاه آزاد اسلامی،1390.

]12] آنتریسر، پ.م و دیگران، راهنمای کاربران عملیات حرارتی، ربیعی، بهناز و دیگران، چاپ اول، تهران، انتشارات جهان نو، 1379.

[13] Ansys Help, Release 13, Mechanical APDL, Advance Analysis Techniques Guidence, Cyclic Symmetry Analysis.

 [14] Tsai G.C., Rotating Vibration Behavior of the Turbine Blades with Different Groups of Blades‚ Journal of Sound and Vibration, Vol. 271, 2004, pp. 547-575.