مطالعه عددی رژیم‌های مختلف شعله در اسپری جریان متقابل آرام

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه تربیت مدرس

2 رئیس پژوهشگاه هوافضای وزارت علوم، تحقیقات و فناوری

10.22034/jfnc.2021.230030.1217

چکیده

شبیه‌سازی عددی دوبعدی شعله اسپری تشکیل‌شده در یک پیکربندی جریان متقابل آرام، به‌منظور بررسی رژیم‌های شعله و تأثیر آن بر تغییرات گونه‌ها و رادیکال‌های مهم، انجام ‌شده است. از اتانول به‌عنوان یک سوخت اسپری مایع استفاده شده و مکانیسم اسکلتی اتانول/هوا با ۴۰ گونه و ۱۸۰ واکنش مقدماتی برای واکنش‌های احتراق به­ کار گرفته شده است. قطرات سوخت با قطر یکسان و به‌صورت تصادفی با استفاده از یک کد UDF در ورودی هوا تزریق می‌شوند و حرکت قطرات براساس دیدگاه لاگرانژی محاسبه شده است. با توجه به نتایج در نسبت­ های هم­ ارزی بالا،  نرخ­ های کرنش بالا و قطرهای بزرگ قطرات، رژیم غالب شعله به‌صورت غیرپیش‌آمیخته است. همچنین، در نواحی مرکز شعله، به ­دلیل صفرشدن مقدار کسر جرمی اکسیدکننده و کاهش مقدار کسر جرمی رادیکال OH در این ناحیه، واکنش‌های احتراقی فرونشانده شده و همچنین مقدار عدد شاخص شعله صفر می‌شود که نشان‌دهندۀ احتراق گروه داخلی قطرات در این ناحیه است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical study of different flame regimes in the laminar counterflow spray

نویسندگان [English]

  • morad havasi 1
  • fathollah ommi 2
  • Fatemeh chitgarha 1
1 Tarbiat Modares University
2 Head of the Aerospace Research Institute of the Ministry of Science, Research and Technology
چکیده [English]

The two-dimensional numerical simulation of the spray flame formed in a laminar counterflow configuration has been performed to investigate flame regimes and its effect on changes in important species and radicals. Ethanol is used as a liquid spray fuel and the skeletal mechanism of ethanol/air with 40 species and 180 preliminary reactions is used for combustion reactions. The Sauter mean diameter of fuel droplets and randomly injected into the air inlet are considered using a UDF code, and the motion of the droplets is calculated using the Lagrangian approach. The results show that the predominant flame regime is Non-Premixed in the high equivalences ratio, high strain rates and large droplet diameters. Also, the combustion reactions are suppressed in the center areas of the flame, due to the reduction of the oxidant fraction and the OH mass fraction, and the flame index is zero, which indicates the internal group of droplets in this area.

کلیدواژه‌ها [English]

  • Configuration of Counter-flow
  • Spray Combustion
  • Laminar Flow
  • premixed
  • non-premixed
  1. H. Watanabe, R. Kurose, S. M. Hwang and F. Akamatsu, “Characteristics of flamelets in spray flames formed in a laminar counterflow,” Combustion and Flame, 148, No. 4, 2007, pp. 234-48.
  2. J. M. Card and F. A. Williams, “Asymptotic analysis with reduced chemistry for the burning of n-heptane droplets,” Combustion and flame,91, No. 2, 1992, pp. 187-99.
  3. N. Peters, “Laminar diffusion flamelet models in non-premixed turbulent combustion,” Progress in energy and combustion science,10, No. 3, 1984, 319-39.
  4. H.H.Chiu andT.M. Liu, “Group combustion of liquid droplets,” Combust. Sci. Technol., 17, No. 3-4, 1977, pp. 127-142.
  5. H. H. Chiu, H. Y. Kim, and E. J. Croke, “Internal group combustion of liquid droplets,” Symp. Combust., 19, No. 1, 1982, pp. 971–980.
  6. H. A. Olguín Astudillo, Theoretical and Numerical Analysis of Laminar Spray Flames for Use in Turbulent Spray Combustion Modeling,Doctoral dissertation, Karls Univercity, 2015.
  7. P. Stapf, H. A. Dwyer and R. R. Maly, “A group combustion model for treating reactive sprays in IC engines,” In Symposium (International) on Combustion, Elsevier, 1998 Jan 1, 27, No. 2, pp. 1857-1864.
  8. S. Candel, F. Lacas, N. Darabiha and J. C. Rolon, “Group combustion in spray flames,” Multiphase Science and Technology, 11, No. 1, pp. 1-18, 1999.
  9. M. Nakamura, F. Akamatsu, R. Kurose and M. Katsuki, “Combustion mechanism of liquid fuel spray in a gaseous flame,” Physics of Fluids, 17, No. 12, 2005, 20123301.
  10. M. Nakamura, F. Akamatsu, R. Kurose and M. Katsuki, “Experimental and numerical study on combustion mechanism of liquid fuel spray entering gaseous flame front,” JSME International Journal Series B Fluids and Thermal Engineering, 49, No. 2, 2006, pp. 498-505.
  11. J. Hayashi, H. Watanabe, R. Kurose and F. Akamatsu, “Effects of fuel droplet size on soot formation in spray flames formed in a laminar counterflow,” Combustion and Flame, 158, No. 12, 2011, pp. 2559-68.
  12. D. Alviso, J. C. Rolon, P. Scouflaire and N. Darabiha, “Experimental and numerical studies of biodiesel combustion mechanisms using a laminar counterflow spray premixed flame,” Fuel, 153, 2015, pp. 154-65.
  13. J. Carpio, D. Martínez-Ruiz, A. Liñán, A. L. Sánchez and F. A. Williams, “Hysteresis in the Vaporization-Controlled Inertial Regime of Nonpremixed Counterflow Spray Combustion,” Combustion Science and Technology, 192, No. 3, 2020, pp. 1-24.
  14. H. M. Amin and W. L. Roberts, “Investigating Soot Parameters in an Ethane/Air Counterflow Diffusion Flame at Elevated Pressures,” Combustion Science and Technology, Published online: 17 Jan 2020, pp. 1-6.
  15. J. Wirtz, B. Cuenot and E. Riber, “Numerical study of a polydisperse spray counterflow diffusion flame,” Proceedings of the Combustion Institute, 38, No. 2, 2021, pp. 3175-3182.
  16. R. King, editor, Active Flow and Combustion Control 2014, Springer International Publishing, Switzerland, 2015.
  17. H. Pitsch “Unsteady flamelet modeling of differential diffusion in turbulent jet diffusion flames,” Combustion and Flame, 123, No. 3, 2000, pp. 358-74.
  18. H. Pitsch and N. Peters, “A consistent flamelet formulation for non-premixed combustion considering differential diffusion effects,” Combustion and flame, 114, No. 1-2, 1998, pp. 26-40.
  19. Fluent AN. “Ansys fluent theory guide,” ANSYS Inc., USA, 2011 Nov, 15317, 724-46.
  20. “ANSYS Fluent Theory Guide,” no. January, 2017.
  21. A. Vié, B. Franzelli, Y. Gao, T. Lu, H. Wang and M. Ihme, “Analysis of segregation and bifurcation in turbulent spray flames: A 3D counterflow configuration,” Proceedings of the Combustion Institute, 35, No. 2, 2015, pp. 1675-83.
  22. V. V. Lissianski, V. M. Zamansky and W. C. Gardiner, Combustion chemistry modeling, InGas-phase combustion chemistry, Springer, New York, NY, 2000.
  23. Z. Manqi, Diphasic Counterflow Flame: Parametric Study, Internship at CERFACS, Toulouse, France, 2010.
  24. S. R. Turns, Introduction to combustion, New York, McGraw-Hill Companies, 1996.
  25. H. Yamashita, M. Shimada and T. Takeno, “A numerical study on flame stability at the transition point of jet diffusion flames,” InSymposium (International) on Combustion, 26, No. 1, 1996, pp. 27-34.
  26. M. Orain and Y. Hardalupas, “Droplet characteristics and local equivalence ratio of reacting mixture in spray counterflow flames,” Experimental thermal and fluid science, 57, pp. 261-74, 2014.
  27. G. Continillo and W. A. Sirignano, “Counterflow spray combustion modeling,” Combustion and Flame,” 81, No. 3-4, 1990, pp. 325-40.
  28. C. Panagopoulos, Theoretical and Numerical Analysis of Laminar Ethanol Spray Flames for the creation of a Spray Flamelet Library, Master Thesis, Mechanical Engineeringat, Delft University of Technology, 2017.