بررسی عددی اثر دمای اولیه بر اشتعال در جریان بدون لایه برشی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی هوافضا دانشگاه صنعتی امیرکبیر

2 دانشگاه صنعتی امیرکبیر

3 دانشگاه صنعتی شریف

4 دانشگاه صنعتی امیرکبیر، دانشکده مهندسی هوافضا

چکیده

در این مقاله، به بررسی فرایند اشتعال در جریان بدون لایه برشی پرداخته می‌شود. در چیدمان بدون لایه برشی دو جریان موازی با سرعت میانگین مساوی به یکدیگر می‌رسند. این چیدمان اجازه مطالعه دقیق شعله‌های لبه‌دار را فراهم می‌کند. هدف اصلی، بررسی اثر دمای اولیه جریان بر مرحله انتشار شعله در فرایند اشتعال است. این کار با استفاده از روش شبیه‌سازی گردابه‌های بزرگ، مدل احتراقی شعله ضخیم‌شده و سینتیک شیمیایی DRM-19 انجام شده است. سرعت محوری میانگین و نوسانی به­دست آمده از دو شبکه ریز و درشت با استفاده از نتایج تجربی اعتبارسنجی شده است. بررسی کسر مخلوط نیز نشان از مناسب­بودن دقت شبیه‌سازی‌ها در پیش‌بینی اختلاط دارد. مکان لبه ‌بالادست و پایین‌دست شعله نیز با نتایج  تجربی مقایسه شده و بیان‌کننده صحت شبیه‌سازی فرایند اشتعال است. سرعت میانگین انتشار شعله لبه‌دار نشان می‌دهد که با افزایش دمای اولیه از 323 به 1000 کلوین، سرعت انتشار شعله از 1 به 2/4 متربرثانیه افزایش پیدا می‌کند. همین روند برای رشد هسته شعله نیز وجود دارد. مقایسه بین سرعت انتشار شعله لبه‌دار به­دست آمده با سرعت انتشار شعله آرام و تصحیح شده آن با مجذور چگالی‌ها نشان می‌دهد که شعله آرام تصحیح ­شده بهترین نتیجه را در پیش‌بینی سرعت انتشار شعله لبه‌دار دارد. همچنین، افزایش دما سبب تبدیل شعله لبه‌دار دوگانه به شعله لبه‌دار سه‌گانه می‌شود.

کلیدواژه‌ها

موضوعات


  1. E. Mastorakos, "Ignition of turbulent non-premixed flames," Progress in Energy and Combustion Science, 35, 2009, pp. 57-97.
  2. Dreizler, S. Lindenmaier, U. Maas, J. Hult, M. Ald´en and C. F. Kaminsk, "Characterisation of a spark ignition system by planar laser-induced fluorescence of OH at high repetition rates and comparison with chemical kinetic calculations," Applied Physics B, 70, 2000, pp. 287-294.
  3. J. V. Pastor, J. M. García-Oliver, A. García and M. Pinotti, "Laser induced plasma methodology for ignition control injection sprays," Energy Conversion and Management, 120, 2016, pp. 144-156.
  4. S. Gashi, J. Hult, K. W. Jenkins, N. Chakraborty, S. Cant and C. F. Kaminski, "Curvature and wrinkling of premixed flame kernels-comparisons of OH PLIF and DNS data," Proceedings of the Combustion Institute, 30, 2005, pp. 809-817.
  5. A. Mulla, S. R. Chakravarthy, N. Swaminathan and R. Balachandran, "Evolution of flame-kernel in laser-induced spark ignited mixtures: A parametric study," Combustion and Flame, 164, 2016, pp. 303-318.
  6. G. Lacaze, E. Richardson and T. Poinsot, "Large eddy simulation of spark ignition in a turbulent methane jet," Combustion and Flame, 156, 2009, pp. 1993-2009.
  7. S. Ahmed and E. Mastorakos, "Spark ignition of lifted turbulent jet flames," Combustion and Flame, 146, 2006, pp. 215-231.
  8. C. Zhi, R. Shaohong and S. Nedunchezhian, "Numerical study of transient evolution of lifted jet flames: partially premixed flame propagation and influence of physical dimensions," Combustion Theory and Modelling, 20, 2016, pp. 592-612.
  9. M. Eidiattarzade, S. Tabejamaat, M. Mani and M. Farshchi, "Studying the Effects of Temperature on Ignition of Methane-air Jet using LES Method," Fuel and Combustion, 9, No. 2, 2016, pp. 1-19. (in persian)
  10. S. Ahmed, R. Balachandran, T. Marchione and E. Mastorakos, "Spark ignition of turbulent nonpremixed bluff-body flames," Combustion and Flame, 151, 2007, pp. 366-385.
  11. V. Subramanian, P. Domingo and L. Vervisch, "Large eddy simulation of forced ignition of an annular bluff-body burner," Combustion and Flame, 157, 2010, pp. 579-601.
  12. Triantafyllidisa, E. Mastorakosa and R. Eggelsb, "Large Eddy Simulations of forced ignition of a non-premixed bluff-body methane flame with Conditional Moment Closure," Combustion and Flame, 156, 2009, pp. 2328-2345.
  13. Eyssartier, B. Cuenot, L. Y. Gicquel and T. Poinsot, "Using LES to predict ignition sequences and ignition probability of turbulent two-phase flames," Combustion and Flame, 160, 2013, pp. 1191-1207.
  14. F. Bourgouin, D. Durox, T. Schuller, J. Beaunier and S. Candela, "Ignition dynamics of an annular combustor equipped with multiple swirling injectors," Combustion and Flame, 160, Issue 8, 2013, pp. 1398-1413.
  15. M. Boileau, G. Staffelbach, B. Cuenot, T. Poinsot and C. Bérat, "LES of an ignition sequence in a gas turbine engine," Combustion and Flame, 154, 2008, pp. 2-22.
  16. M. Klein, N. Chakraborty, K. W. Jenkins and R. S. Cant, "Effects of initial radius on the propagation of premixed flame kernels in a turbulent environment," Physics of Fluids, 18, 055102, 2006,.
  17. S. Chung, "Stabilization, propagation and instability of tribrachial triple flames," Proceeding of the Combustion Institue, 31, 2007, pp. 877-892.
  18. Buckmaster, "Edge-flames," Progress in Energy and Combustion Science, 28, 2002, pp. 435-475.
  19. EidiAttarzade, S. Tabejamaat, M. Mani and M. Farshchi, "Numerical study of ignition process in turbulent shear-less methane-air mixing layer," Flow, Turbulence and Combustion, 99, 2017, pp. 411-436.
  20. S. F. Ahmed and E. Mastorakos, "Spark ignition of a turbulent shear-less fuel–air mixing layer," Fuel, 164, 2016, pp. 297-304.
  21. K. M., "Toward an understanding of the stabilization mechanism of lifted turbulent jet flames: experiments," Prog Energy Combust Sci, 33, 2007, pp. 211-231.
  22. V. Favier and L. Vervisch, "Investigating the effects of edge flames in liftoff in non-premixed turbulent combustion," Proceeding Combust Institue, 27, 1998, pp. 1239-1245.
  23. Y. Mizobuchi, S. Tachibana, J. Shinio, S. Ogawa and T. Takeno, "A numerical analysis of the structure of a turbulent hydrogen jet lifted flame," Proc Combust Inst, 29., 2002, pp. 2009-2015.
  24. J. Oh and Y. Yoon, "Flame stabilization in a lifted non-premixed turbulent hydrogen jet with coaxial air," International J. of Hydrogen Energy, 35, 2010, pp. 10596-10597.
  25. M. Briones, S. K. Aggarwal and V. R. Katta, "Effect of H2 enrichment on the propagation characteristics of CH4-air triple flames," Combustion and Flame, 153, 2008, pp. 367-383.
  26. S. Yoo and H. G. Im, "Transient dynamics of edge flames in a laminar nonpremixed hydrogen-air counterflow," Proceeding of the Combustion Institue, 30, 2005, pp. 349-356.
  27. R. Owston and J. Abraham, "Exploratory studies of modeling approaches for hydrogen triple flames," International J. of Hydrogen Energy, 36, 2011, pp. 8570-8582.
  28. S. VEERAVALLI and Z. WARHAFT, "The shearless turbulence mixing layer," Journal of Fluid Mechanics, 207, 1989, pp. 191-229.
  29. L. Mydlarski and Z. Warhaft, "On the onset of high-Reynolds-number grid-generated wind tunnel turbulence," Journal of Fluid Mechanics, 320, 1996, pp. 331-368.
  30. S. Gerashchenko, G. Goodand and Z. Warhaft, "Entrainment and mixing of water droplets across a shearless turbulent interface with and without gravitational effects," Journal of Fluid Mechanics, 668, 2011, pp. 293-303.
  31. G. H. Good,  S. Gerashchenko and  Z. Warhaft, "Intermittency and inertial particle entrainment at a turbulent interface: the effect of the large­scale eddies," Journal of Fluid Mechanics, 694, 2012, pp. 371-398.
  32. P. J. Ireland and L. R. Collins, "Direct numerical simulation of inertial particle entrainment in a shearless mixing layer," Journal of Fluid Mechanics, 704, 2012, pp. 301-332.
  33. Fathali and M. K. Deshiri, "Sensitivity of the two-dimensional shearless mixing layer to the initial turbulent kinetic energy and integral length scale," Physical Review E, 93, 043122, 2016.
  34. E. Mastorakos, T. A. Baritaud and T. J. Poinsot, "Numerical Simulations of Autoignition in Turbulent Mixing Flows," Combustion and Flam E, 109, 1997, pp. 198-223.
  35. Ma and Z. Warhaft, "Some aspects of the thermal mixing layer in grid turbulence," Physics of Fluids, 29, 1986, pp. 3114-3120.
  36. T. Poinsot and D. Veynante, Theoretical and Numerical Combustion, Philadelphia, USA, Edwards, 2005.
  37. J. Smagorinsky, "General Circulation Experiments With The Primitive Equations," Monthly Weather Review, 91, 1963, pp. 99-164.
  38. L. Gicquel, G. Staffelbach and T. Poinsot, "Large Eddy Simulation of gaseous flames in gas turbine combustion chambers," Progress in Energy and Combustion Science, 38, 2012, pp. 782-817.
  39. S. B. Pope, Turbulent Flows, Cambridge, United Kingdom, Cambridge Univesity Press, 2000.
  40. T. Butler and P. Rourke, "A numerical method for two dimensional unsteady reacting flows," Symposium (International) on Combustion, 16, 1977, pp. 1503-1515.
  41. Colin, F. Ducros, D. Veynante and T. Poinsot, "A thickened flame model for large eddy simulations of turbulent premixed combustion," Physics of Fluids, 12, 2000, pp. 1843-1863.
  42. M. Shahsavari, M. Farshchi and M. H. Arabnejad, "Large Eddy Simulations of Unconfined Non-reacting and Reacting Turbulent Low Swirl Jets," Flow, Turbulence and Combustion, 98, 2017, pp. 817-840.
  43. H. G. Weller, G. Tabor, H. Jasak and C. Fureby, "A tensorial approach to computational continuum mechanics using object-oriented techniques," Computers in Physics, 12, 1998, pp. 620-631.
  44. R. Issa, "Solution of the implicitly discretized fluid flow equations by operator splitting," Journal of Computational Physics, 62, 1986, pp. 40-65.
  45. N. Kornev and E. Hassel, "Method of random spots for generation of synthetic inhomogeneous turbulent fields with prescribed autocorrelation functions," Communications in Numerical Methods In Engineering, 23, 2007, pp. 35-43.
  46. Kazakov and M. Frenklach, http://www.me.berkeley.edu/drm/, Accessed 2 Jau 2018.
  47. R. W. Bilger, "The Structure of Diffusion Flames," Combustion Science and Technology, 13 , 1976, pp. 155-170.