تأثیر اصطکاک و لقی در یاتاقان های کمکی بر ارتعاشات آشوبناک یک روتور هم محور با یاتاقان های مغناطیسی فعال

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری / دانشکده مهندسی مکانیک، دانشگاه صنعتی اصفهان، اصفهان

2 عضو هیات علمی / دانشکده مهندسی مکانیک، دانشگاه صنعتی اصفهان، اصفهان

3 عضو هیات علمی / دانشکده مهندسی هوافضا، دانشگاه علوم و فنون هوایی شهید ستاری، تهران

چکیده

در بسیاری از سیستم­های دوار همچون موتورهای جت، برای انتقال توان بین قسمت­های فشار بالا و فشار پایین توربین و کمپرسور از سیستم روتور هم­محور استفاده می­شود. در این مقاله تحلیل آشوبناک یک سیستم روتور هم­محور تعلیق‌شده به‌صورت مغناطیسی در یاتاقان‌های کمکی ارائه شده است که شامل ممان­های ژیروسکوپی دیسک­ها و کوپلینگ هندسی قطب­های مغناطیسی است. معادلات دیفرانسیل غیرخطی حرکت با استفاده از معادلات لاگرانژ استخراج و با روش عددی رونگ - کوتا حل شده­اند. سپس آثار اصطکاک و لقی در یاتاقان­های کمکی روی ارتعاشات آشوبناک سیستم روتور هم­محور - یاتاقان مغناطیسی فعال، با استفاده از مسیرهای مداری، طیف توان، مقاطع پوانکاره، نمودارهای دوشاخگی و ماکزیمم نماهای لیاپانوف بررسی شده است. نتایج نشان می­دهد که با تغییر این پارامترها، دینامیک سیستم می­تواند به‌طور قابل ملاحظه­ای تحت تأثیر قرار گیرد؛ به‌طوری‌که پاسخ­های سیستم پدیده­های دینامیک غیرخطی متنوعی را از جمله آشوب و پرش آشکار می­کنند. همچنین با توجه به نتایج تحلیل، برخی مقادیر آستانه­ای را می­توان در ارتباط با طراحی پارامترهای مناسب برای این سیستم به‌دست آورد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Influence of friction and clearance in auxiliary bearings on chaotic vibration of a coaxial rotor supported by active magnetic bearings

نویسندگان [English]

  • Reza Ebrahimi 1
  • Mostafa Ghayour 2
  • Heshmatallah Mohammad Khanlo 3
1 PhD Student / Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran
2 Professor / Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran
3 Asistant Professor / Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran
چکیده [English]

In many cases of rotating systems, like jet engines, coaxial rotor system is used for power transmission between a high/low pressure turbine and a compressor. In this paper, chaos analysis of a magnetically supported coaxial rotor system in auxiliary bearings is presented, which includes gyroscopic moments of disks and geometric coupling of the magnetic actuators. The nonlinear equations of motion are developed using the Lagrange’s equations and solved by the Rung-Kutta method. Then, the effects of friction and clearance in auxiliary bearings on the chaotic vibration of the coaxial rotor-AMB system are investigated by the dynamic trajectories, power spectra, Poincare´ maps, bifurcation diagrams and maximum Lyapunov exponents. The results show that dynamics of the system can be significantly affected by varying these parameters, so that the system responses reveal a rich variety of nonlinear dynamical phenomena including chaos and jump. Also according to the results of analysis, some threshold values can be obtained with regard to the design of appropriate parameters for this system.

کلیدواژه‌ها [English]

  • Coaxial rotor
  • Active magnetic bearing (AMB)
  • Auxiliary bearing
  • Nonlinear dynamic
  • Bifurcation

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