مطالعه تجربی تاثیر نسبت انسداد انژکتور کم چرخش بر حدود پایداری و رژیم های احتراقی شعله گاز طبیعی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد هوافضا-پیشرانش

2 استادیار گروه مهندسی هوافضا دانشکده فناوریهای نوین دانشگاه شهید بهشتی

چکیده

در این مطالعه، به بررسی تاثیر نسبت انسداد چرخاننده کم­ چرخش بر حدود پایداری و رژیم­ های احتراقی شعله پرداخته می ­شود. نسبت انسداد برابر سطح مسدود و پوشیده صفحه مغشوش­ کننده  به کل مساحت آن است و یکی از پارامترهای اصلی چرخاننده کم­ چرخش است که تاثیر مهمی بر پایداری شعله کم ­چرخش دارد. به­ منظور بررسی تاثیر نسبت انسداد کانال مرکزی چرخاننده بر پایداری، 9 چرخاننده با هندسه متمایز مورد بررسی قرار گرفتند. نتایج نشان داد که با افزایش نسبت انسداد، حد خاموشی چرخاننده­ ها کاهش می ­یابد، به طوری که با افزایش نسبت انسداد از 43% تا 76%، میزان حد خاموشی تا حدود 25% کاهش یافته و پایداری شعله بهبود می ­یابد. همچنین، در این مطالعه مشاهده شد که با افزایش نسبت هم ­ارزی، شعله یک فرایند گذار را طی می کند که در آن شعله از یک حالت Vشکل (کاسه­ ای شکل) معلق پایدار تا حالت گردابه­ ای­ شکل متصل به دهانه مشعل پیش می ­رود. فرایند گذار را می­توان به سه رژیم احتراقی متفاوت تقسیم کرد که حدود این رژیم­ های احتراقی براساس نسبت هم ­ارزی و میزان عدد رینولدز ورودی مشعل تعیین می­شود. بررسی میزان آلاینده  چرخاننده­ ها نشان داد که میزان  با افزایش نسبت هم ­ارزی افزایش می ­یابد و در نسبت­ های  هم ­ارزی نزدیک 1 میزان  در حدود ppm20 است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental study of the effects of low swirl injector blockage ratio on stability limits and combustion regimes of natural gas flame

نویسندگان [English]

  • Navid Heshmati 1
  • seyyed mehdi mirsajedi 2
1 New technologies department shahid beheshti university Tehran iran
2 New technologies department shahid beheshti university Tehran iran
چکیده [English]

In this study, the effect of a low swirl injector blockage ratio on the flame stability limits is investigated by using a low swirl burner. The blockage ratio is one of the main geometrical parameters of the low-swirl injector which has a significant impact on the stability of the flame. In order to investigate the influence of the blockage ratio of the central channel of low swirl injector on stability, nine swirler with distinct geometries were investigated. The results showed that with increasing the blockage ratio, the flame extinction limit was reduced so that increasing the blockage ratio from 43% to 76% reduced the extinction limit to about 25% and improved flame stability. It was also observed in this study that by increasing the equivalence ratio, the flame undergoes a transition process in which the flame proceeds from a stable lifted bowl shape to a vortex shape attached to the burner nozzle. The transition process can be divided into three different combustion regimes and in this study, these limits presented based on the equivalence ratio and the Reynolds number of the burner inlet. Evaluation of NOx pollutants of swirlers showed that Nox increased with increasing equivalence ratio and at equivalence ratios near stoichiometric values, the Nox level was about 20 ppm.

کلیدواژه‌ها [English]

  • Low swirl combustion
  • flame stability
  • blockage ratio
  • natural gas

مراجع

  1. D. T. Yegian and R. K. Cheng, “Stability characteristics and emission levels of a laboratory hot water heater utilizing a weak-swirl burner,” American Flame Research Council Fall International Symposium, Berkeley, California, USA, 1995.
  2. N. Syred and J. M. Beér, “Combustion in swirling flows: A review,” Combustion and Flame, 23, No. 2, 1974, pp. 143-201.
  3. C. K. Chan, K. S. Lau, W. K. Chin and R. K. Cheng RK, “Freely propagating open premixed turbulent flames stabilized by swirl,” Symposium (International) on Combustion, 24, No. 1, 1992, pp. 511–518.
  4. D. T. Yegian and R. K. Cheng, Development of a vane-swirler for use in a low NOx weak-swirl burner, Office of Scientific and Technical Information (OSTI), Technical Report, DE97001252, 1996.
  5. D. T. Yegian, R. K. Cheng, “Scaling the weak-swirl burner from 15 kW to 1 MW,” Combustion Institute meeting, Berkely, California, United States, 1998.
  6. R. K. Cheng, D. T. Yegian, M. M. Miyasato, G. S. Samuelsen, C. E. Benson, R. Pellizzari and et al, “Scaling and development of low-swirl burners for low-emission furnaces and boilers”, Proceedings of the Combustion Institute, 28, No. 1, 2000, pp. 1305–1313.
  7. M. R. Johnson, D. Littlejohn, W. A. Nazeer, K. O. Smith and R. K. Cheng, “A comparison of the flowfields and emissions of high-swirl injectors and low-swirl injectors for lean premixed gas turbines,” Proceedings of the Combustion Institute, 30, No. 2, 2005, pp. 2867–2874.
  8. M. Farshchi and N. D. Tohidi ND, “Experimental Investigation of a lean premixed low swirl burner emissions,” 3rd Fuel and Combustion Conference of Iranian Combustion Institute, Tehran, Iran, 2010. (in Persian)
  9. M. Shahsavari and M. Farshchi, “Experimental Investigation of the effects of geometrical parameters of low swirl burner on flame stability,” 10th International Conference of Iranian Aerospace Society, Tehran, Iran, 2011. (in Persian)
  10. M. Shahsavari and M. Farshchi, “Stability Characteristics and NOx Emissions of Low Swirl Flames,” Fuel and Combustion, 5, No. 2, 2013, pp. 59-75. (in Persian)
  11. S. I. Pishbin, S. M. Modares Razavi and M. Ghazikhani, “Investigation of the effects of performance parameters on the flame behavior and temperature distribution and exergy analysis of low swirl premixed burners,” Modares Mechanical Engineering, 14, 2014, pp. 27-38. (in Persian)
  12. P. L. Therkelsen, D. Littlejohn and R. K. Cheng, “Parametric Study of Low-Swirl Injector Geometry on its Operability”, Volume 2: Combustion, Fuels and Emissions, Parts A and B. Presented at the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, Copenhagen, Denmark, 2012.
  13. A. A. Verbeek, T. W. F. M. Bouten, G. G. M. Stoffels, B. J. Geurts and T. H. van der Meer, “Fractal turbulence enhancing low-swirl combustion,” Combustion and Flame, 162, 2015, pp. 129-143.
  14. A. A. Verbeek, P. A. Willems, G. G. M. Stoffels, B. J. Geurts and T. H. van der Meer, “Enhancement of turbulent flame speed of V-shaped flames in fractal-grid-generated turbulence,” Combustion and Flame, 167, 2016, pp. 97-112.
  15. G. D. ten Thij, A. A. Verbeek and T. H. van der Meer, “Application of Fractal Grids in Industrial Low-Swirl Combustion,” Flow, Turbulence and Combustion, 96, 2016, pp. 801-818.
  16. M. Nahvi, K. Mazaheri, M. M. Parsafar and A. Mohammadpour, “Experimental analysis of blockage effect on low-swirl burner combustion parameters for lean premixed natural gas-air flames,” 18th Fluid Dynamics Conference, Mashhad, Iran, 2019.
  17. A. Frank, P. Therkelsen, M. Sierra Aznar, V. H. Rapp, R. K. Cheng and J. Y. Chen, “Investigation of the Down-Scaling Effects on the Low Swirl Burner and its Application to Microturbines,” ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, American Society of Mechanical Engineers, Oslo, Norway, 2018.
  18. J. M. Beér and N. A. Chigier, “Combustion Aerodynamics,” New York, Halsted Press Division. Wiley, 1972.
  19. R. K. Cheng, S. A. Fable, D.Schmidt, L. Arellano, K. O. Smith, “Development of a low swirl injector concept for gas turbines,” International Joint Power Conference, 2001.
  20. N. Heshmati, Design and Development of A Premixed Low Swirl Burner with The Approach of Applying The LSB In Microturbines, Msc Disseration, Department of New Technologies Engineering, Tehran: Shahid Beheshti University, 2019. (in Persian)
  21. N. Heshmati and S. M. Mirsajedi, “Experimental Investigation of low swirl burner flame stability,” 4th National Conference of Iranian Aerospace Propulsion Association, 2018. (in Persian)
  22. D. Littlejohn, R. K. Cheng, D. R. Noble and T. Lieuwen, “Laboratory Investigations of Low-Swirl Injectors Operating With Syngases,” Journal of Engineering for Gas Turbines and Power, 132, 2010, pp. 30-38.
  23. D. Beerer, Combustion characteristics and performance of low-swirl injectors with natural gas and alternative fuels at elevated pressures and temperatures, PhD Disseration, Department of Aerospace Engineering, Irvine: University of California, 2013.
  24. R. K. Cheng, D. Littlejohn, P. A. Strakey and T. Sidwell, “Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions,” Proceedings of the Combustion Institute, 32, 2009, pp. 3001-3009.
  25. R. K. Cheng, D. Littlejohn, W. A. Nazeer, K. O. Smith, “Laboratory Studies of the Flow Field Characteristics of Low-Swirl Injectors for Adaptation to Fuel-Flexible Turbines,” Volume 1: Combustion and Fuels, Education. Presented at the ASME Turbo Expo 2006: Power for Land, Sea, and Air, Barcelona, Spain, 2006.

فایل ها

سابقه مقاله

  • تاریخ دریافت: 17 اردیبهشت 1399
  • تاریخ بازنگری: 21 خرداد 1399
  • تاریخ پذیرش: 25 خرداد 1399

هم رسانی

ارجاع به این مقاله

آمار