تحقیق تجربی و عددی ضریب اثربخشی خنک‌کاری لایه‌ای در نوک پره توربین دارای اسکوئیلر

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه علم و صنعت

2 دانشکده مکانیک / دانشگاه علم و صنعت / تهران / ایران.

3 دانشکده مهندسی مکانیک / دانشگاه علم و صنعت ایران / تهران / ایران

چکیده

در کار تحقیقاتی حاضر، به بررسی اثر حضور اسکوئیلر در بهبود عملکرد آیرودینامیکی و توزیع بار حرارتی در ناحیه نوک پره پرداخته شده است. ابتدا اثر چهار نسبت دمش مختلف بر روی عملکرد خنک‌کاری نوک پره دارای اسکوئیلر به‌صورت تجربی و با استفاده از روش اندازه‌گیری انتقال حرارت در حالت پایا بررسی شده است. سپس با بهره‌گیری از رهیافت معادلات ناویر-استوکس به روش میانگین‌گیری رینولدز به بررسی عملکرد خنک‌کاری و افت‌های آیرودینامیکی در نوک پره تخت و دارای اسکوئیلر پرداخته شده است. نتایج حاصل از تحقیقات تجربی نشان می‌دهد در پره دارای اسکوئیلر، با افزایش نسبت دمش، مناطق وسیع‌تری از نوک پره تحت پوشش سیال خنک‌کننده قرار می‌گیرند. نتایج شبیه‌سازی عددی نشان می‌دهد، در تمام نسبت دمش‌ها، متوسط اثربخشی در سطح پروفیل پره با نوک تخت کمتر از پره دارای اسکوئیلر است. در پره دارای اسکوئیلر، با افزایش نسبت دمش، مقدار متوسط ضریب انتقال حرارت در سطح پروفیل پره‌ با نوک تخت و دارای اسکوئیلر به ترتیب به مقدار 43% و44% کاهش پیدا کرده و متوسط ضریب اثربخشی بر روی لبه داخلی اسکوئیلر و سطح بالای اسکوئیلر به ترتیب 23% و 15% افزایش پیدا می‌کند. ضمنا با بالا رفتن نسبت دمش، انتقال حرارت در سطوح ذکرشده کاهش پیدا می‌کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental and Numerical Investigation of Film Cooling Effectiveness on Squealer Tip of a Turbine Blade

نویسندگان [English]

  • Reza Taghavi Zenouz 1
  • Pantheia Peikani 2
  • Ali Akbarzadeh 3
1 School of Mechanical Engineering/ Iran University of Science and Technology/ Tehran / Iran
2 School of Mechanical engineering / Iran University of Science and Technology / Tehran / Iran
3 School of Mechanical Engineering / Iran University of Science and Technology / Tehran / Iran
چکیده [English]

In this article, the effects of squealer on aerodynamic performance and thermal load distribution on the blade tip region are investigated. Experimental results are presented at blowing ratios of 0.5, 0.75, 1.0, and 1.5. The film-cooling effectiveness is measured via the steady-state heat transfer measurement technique. A numerical approach has been applied to compare the film cooling performance and aerodynamic losses in the plane and recessed blade tips. The experimental results indicate that, as the blowing ratio increases, the coolant jets provide better cooling coverage on the cavity surface. The numerical results show that the plane tip film-cooling effectiveness is lower than that for the squealer tip. It can be observed that, for the plane and squealer tip configurations, as the blowing ratio increased, the heat transfer coefficient decreased by about 43% and 44%, respectively. Moreover, the film-cooling effectiveness on squealer tip surface and rim walls increased by 15% and 23%, respectively. Furthermore, the lower heat transfer coefficient was observed at a higher blowing ratio on the surfaces mentioned above. The squealer tip geometry showed better aerodynamic performance, which results in weaker tip leakage vortex and lower tip leakage flow rate with respect to the plane tip geometry.

کلیدواژه‌ها [English]

  • Axial Turbine
  • External cooling
  • Squealer
  • Film-cooling effectiveness
  • Aerodynamic performance
[1] S.W. Lee, S.U. Kim, K.H. Kim, Aerodynamic performance of winglets covering the tip gap inlet in a turbine cascade, International Journal of Heat and Fluid Flow, 34 (2012) 36-46.
[2] S. Naik, C. Georgakis, T. Hofer, D. Lengani, Heat transfer and film cooling of blade tips and endwalls, Journal of Turbomachinery, 134(4) (2012) 041004.
[3] S. Acharya, H. Yang, S.V. Ekkad, C. Prakash, R. Bunker, Numerical simulation of film cooling on the tip of a gas turbine blade, in:  ASME Turbo Expo 2002: Power for Land, Sea, and Air, American Society of Mechanical Engineers Digital Collection, 2002, pp. 1051-1062.
[4] J. Christophel, K.A. Thole, F. Cunha, Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part II: Heat Transfer Measurements, J. Turbomach., 127(2) (2005) 278-286.
[5] H. Nasir, S.V. Ekkad, R.S. Bunker, Effect of tip and pressure side coolant injection on heat transfer distributions for a plane and recessed tip, Journal of Turbomachinery, 129(1) (2007) 151-163.
[6] M. Rezasoltani, K. Lu, M.T. Schobeiri, J.-C. Han, A combined experimental and numerical study of the turbine blade tip film cooling effectiveness under rotation condition, Journal of Turbomachinery, 137(5) (2015) 051009.
[7] Y.C. Nho, Y.J. Lee, J.S. Kwak, Effects of tip shape on the gas turbine blade tip heat transfer, Journal of Thermophysics and Heat Transfer, 26(2) (2012) 305-312.
[8] J.S. Park, D.H. Lee, D.-H. Rhee, S.H. Kang, H.H. Cho, Heat transfer and film cooling effectiveness on the squealer tip of a turbine blade, Energy, 72 (2014) 331-343.
[9] F. Cheng, H. Chang, J. Zhang, X. Tian, Effect of film-hole configuration on film-cooling effectiveness of squealer tips, Journal of Thermal Science and Technology, 12(1) (2017) JTST0004-JTST0004.
[10] E. Eckert, Analysis of film cooling and full-coverage film cooling of gas turbine blades, Journal of Engineering for Gas Turbines and Power, 106(1) (1984) 206-213.
[11] D.G. Bogard, K.A. Thole, Gas turbine film cooling, Journal of propulsion and power, 22(2) (2006) 249-270.
[12] H. Consigny, B. Richards, Short duration measurements of heat-transfer rate to a gas turbine rotor blade, Journal of Engineering for Power, 104(3) (1982) 542-550.
[13] E. Eckert, Similarity analysis of model experiments for film cooling in gas turbines, Wärme-und Stoffübertragung, 27(4) (1992) 217-223.
[14] O. Hassan, I. Hassan, Experimental investigations of the film cooling effectiveness of a micro-tangential-jet scheme on a gas turbine vane, International Journal of Heat and Mass Transfer, 61 (2013) 158-171.
[15] R.J. Moffat, Describing the uncertainties in experimental results, Experimental thermal and fluid science, 1(1) (1988) 3-17.
[16] F.-n. Cheng, J.-z. Zhang, H.-p. Chang, J.-y. Zhang, Investigations of film-cooling effectiveness on the squealer tip with various film-hole configurations in a linear cascade, International Journal of Heat and Mass Transfer, 117 (2018) 344-357.
[17] K. He, Investigations of film cooling and heat transfer on a turbine blade squealer tip, Applied Thermal Engineering, 110 (2017) 630-647.
[18] I. Sadrehaghighi, Essentials of Turbomachinery in CFD, 2019.
[19] H. Li, X. Su, X. Yuan, Entropy Analysis of the Flat Tip Leakage Flow with Delayed Detached Eddy Simulation, Entropy, 21(1) (2019) 21.
[20] L. Kavurmacioglu, H. Maral, C.B. Senel, C. Camci, Performance of partial and cavity type squealer tip of a HP turbine blade in a linear cascade, International Journal of Aerospace Engineering, 2018 (2018).
[21] W. Li, W.-y. Qiao, K.-f. Xu, H.-l. Luo, Numerical simulation of tip clearance flow passive control in axial turbine, Journal of Thermal Science, 17(2) (2008) 147-155.
[22] H. Ma, L. Wang, Experimental study of effects of tip geometry on the flow field in a turbine cascade passage, Journal of Thermal Science, 24(1) (2015) 1-9.
[23] H. Maral, C.B. Senel, L. Kavurmacioglu, C. Camci, Aerothermal performance of partial and cavity squealer tip in a linear turbine cascade, in:  Proceedings of the 2nd International Conference on Advances in Mechanical Engineering, Istanbul, Turkey, 2016.
[24] J.S. Kwak, J.-C. Han, Heat transfer coefficients and film cooling effectiveness on the squealer tip of a gas turbine blade, Journal of Turbomachinery, 125(4) (2003) 648-657.
[25] Z. Zhou, S. Chen, W. Li, S. Wang, Thermal performance of blade tip and casing coolant injection on a turbine blade with cavity and winglet-cavity tip, International Journal of Heat and Mass Transfer, 130 (2019) 585-602.
[26] J. Kim, W. Seo, M. Bang, S.H. Kim, S.M. Choi, H.H. Cho, Effect of Shelf Squealer Tip Configurations on Film Cooling Effectiveness, in:  ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, American Society of Mechanical Engineers Digital Collection, 2018.