اهمیت استفاده از مدل احتراقی و زیرشبکه‏‌ی مناسب به‌منظور مدل‌سازی الگوی جریان در آتش استخری بزرگ‌مقیاس

نوع مقاله : مقاله پژوهشی

نویسندگان

1 تربیت مدرس

2 تربیت مدرس * مهندسی مکانیک

چکیده

در این مقاله به کمک روش شبیه‌سازی گردابه‌های بزرگ رفتار آتش استخری بزرگ مقیاس مورد بررسی قرار گرفته است. به منظور بررسی کارایی مدل‌های احتراقی مختلف در شبیه‌سازی آتش و همچنین بررسی سازگاری مدل احتراقی با مدل زیرشبکه، دو مدل احتراقی اضمحلال گردابه و سینتیک سریع در دو حالت مدل زیرشبکه اسماگورینسکی و تک معادله‌ای، مورد ارزیابی قرارگرفته شد. در حالت کلی مدل احتراقی سینتیک سریع با پیش­بینی بیش از حد احتراق، میزان سرعت و دما را مقداری بیشتر از نتایج تجربی مدل می­کند، اما مدل احتراقی اضمحلال گردابه به علت استفاده از زمان مشخص ه اغتشاشی و نفوذ می‌تواند احتراق را دقیق‌تر مدل کند و در نتیجه نتایج میدان سرعت و دما را دقیق­تر پیش­بینی می‌کند. همچنین مدل احتراقی اضمحلال گردابه در حالتی که از مدل زیرشبکه تک معادله‌ای استفاده شود، بهترین مدل در پیش­بینی میدان سرعت است به نحوی که در مقاطعی از میدان حل با اختلاف حدود 10 - 5 درصد در محدود ه نتایج تجربی قرار می‌گیرد، اما مدل احتراقی سینتیک سریع بر خلاف مدل اضمحلال گردابه زمانی که با از مدل زیرشبکه اسماگورینسکی استفاده شود، نتایج بهتری ارائه می‌دهد و زمان یکه با مدل زیرشبکه تک معادله‌ای به کار رود، نتایج میدان سرعت را با دقت پائین‌تری، مدل می‌کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The Importance of the Compatible Combustion and Sub-grid Scale Models on the Simulation of Large-Scale Pool Fire

نویسندگان [English]

  • Ghassem Heidarinejad 1
  • Hadi PasdarShahri 2
  • mohamad safarzadeh 1
1 Faculty of Mechanical Engineering, Tarbiat Modares University
2 Assistant Professor, Faculty of Mechanical Engineering, Tarbiat Modares University
چکیده [English]

In this paper, large-scale pool fire behavior has been investigated with large eddy simulation. In order to investigate the efficiency of various combustion models in the pool fire simulation, two combustion models of the eddy dissipation model and infinite fast chemistry in two sub-grid scale models of Smagorinsky and one equation was evaluated. The infinite fast chemistry model has an over- prediction in the reaction rate and flame temperatures in the simulation of pool fire. In addition, the eddy dissipation model, due to the use of time characteristic of turbulence and diffusion, has more accurate results in the prediction temperature field and flow behaviors. The eddy dissipation model with one- equation sub-grid scale model has better prediction for the velocity field and there is a difference of about 5–10 % with the experimental measurements. However, the infinite fast chemistry combustion model can better fit with the Smagorinsky sub-grid scale than one equation sub-grid scale model in the simulation of pool fire. The numerical results predicted by the different combustion models and sub-grid models for vertical velocity along the central line are in the range of experimental results, and almost all models predict the vertical velocity in this line, good.

کلیدواژه‌ها [English]

  • Pool fire؛ Eddy dissipation
  • Infinite fast chemistry combustion model
  • Smagorinsky
  • one-equation sub-grid
[1]   B.J. McCaffrey, Entrainment and heat flux of buoyant diffusion flames, NBSIR, (1982) 82- 2473.
[2]   B. McCaffrey, Purely buoyant diffusion flames: Some experimental results. Final Report,  Chemical  and  Physical   Processes in Combustion. The National Institute of Standards and Technology (NIST), Miami Beach, (1979) 49.
[3]  A.A. Attar, M. Pourmahdian, B. Anvaripour, Experimental study and CFD simulation of pool fires, International Journal of Computer Applications, 70(11) (2013).
[4]  H. Pasdarshahri, G. Heidarinejad, K. Mazaheri, Comparison of Turbulence Sub-Grid Scale Model for Modeling of Large  Scale  Pool  Fire Using LES, Energy: Engineering & Managment, 3(1) (2013) 52-61 (In Persian).
[5]   K. McGrattan, R. Rehm, H. Baum, Fire-driven flows in enclosures, Journal of Computational Physics, 110(2) (1994) 285-291.
[6]    B. Sun, K. Guo, V.K. Pareek, Dynamic simulation of hazard analysis of radiations from LNG pool fire, Journal of Loss Prevention in the Process Industries, 35 (2015) 200-210.
[7]   W. Chow, R. Yin, A new model on simulating smoke transport with computational fluid dynamics, Building and Environment, 39(6) (2004) 611-620.
[8]  W. Chow, J. Dang, Y. Gao, C. Chow, Dependence of flame height of internal fire whirl in a vertical shaft on fuel burning rate in pool fire ,Applied Thermal Engineering, 121 (2017) 712-720.
[9]    H.Z. Chiew, Fire dynamics simulation (FDS) study of fire in structures with curved geometry, UTAR, 2013.
[10] H. Xue, J. Ho, Y. Cheng, Comparison of different combustion models in enclosure fire simulation, Fire Safety Journal, 36(1) (2001) 37-54.
[11] Y.-L. Huang, H.-R. Shiu, S.-H. Chang, W.-F. Wu, S.-L. Chen, Comparison of combustion models in cleanroom fire, Journal of Mechanics, 24(3) (2008) 267-275.
[12] G. Yeoh, R. Yuen, S. Chueng, W. Kwok, On modelling combustion, radiation and soot processes in compartment fires, Building and Environment, 38(6) (2003) 771-785.
[13]  D. Yang, L. Hu, Y. Jiang, R. Huo, S. Zhu, X. Zhao, Comparison of FDS predictions by different combustion models with measured data for enclosure fires, Fire Safety Journal, 45(5) (2010) 298-313.
[14]G. Yeoh, S. Cheung, J. Tu,  T. Barber, Comparative Large Eddy Simulation  study  of a large-scale buoyant fire, Heat and mass transfer, 47(9) (2011) 1197-1208.
[15] G. Maragkos, B. Merci ,Large Eddy simulations of CH4 fire plumes, Flow, Turbulence and Combustion, 99(1) (2017) 239-278.
[16]H. Pasdarshahri, G. Heidarinejad, K. Mazaheri, Large eddy simulation on one-meter methane pool fire using one-equation sub-grid scale model, in: MCS, pp. 11-15.
[17]H. pasdarshahri, improved of compatible subgrid scale with Large Eddy Simulation for numerical simulation of fire in closed space, PhD Thesis, Tarbiat Modares University, Iran, 2013 (In Persian).
[18]   A. Yuen, G. Yeoh, V. Timchenko, S. Cheung, T. Chen ,Study of three LES subgrid-scale turbulence models for predictions of heat and mass transfer in large-scale compartment fires, Numerical Heat Transfer, Part A: Applications, 69(11) (2016) 1223-1241.
[19]   A.C. Yuen, G.H. Yeoh, V. Timchenko, S.C. Cheung, Q.N. Chan, T. Chen, On the influences of key modelling constants of large eddy simulations for large-scale compartment fires predictions, International Journal of Computational Fluid Dynamics, 31(6-8) (2017) 324-337.
[20]G. Maragkos, T. Beji,  B.  Merci, Advances in modelling in CFD simulations of turbulent gaseous pool fires, Combustion and Flame, 181 (2017) 22-38.
[21] O.M. Knio, H.N. Najm, P.S. Wyckoff, A semi- implicit numerical scheme for reacting flow: II. Stiff, operator-split formulation, Journal of Computational Physics, 154(2) (1999) 428- 467.
[22]T. Poinsot, D. Veynante, Theoretical and numerical combustion, RT Edwards, Inc., 2005.
[23]R.O. Fox, A. Varma, Computational models for turbulent reacting flows, Cambridge Univ. Press, 2003.
[24]A. Yuen ,G. Yeoh, V. Timchenko, T. Barber, LES and multi-step chemical reaction in compartment fires, Numerical Heat Transfer, Part A: Applications, 68(7) (2015) 711-736.
[25]G.-H. Yeoh, K.K. Yuen, Computational fluid dynamics in fire engineering: theory, modelling and practice, Butterworth-Heinemann, 2009.
[26]T. Echekki, E. Mastorakos, Turbulent combustion modeling: Advances, new trends and perspectives, Springer Science & Business Media, 2010.
[27]B.F. Magnussen, B.H. Hjertager, On mathematical modeling of turbulent combustion with special emphasis on soot formation and combustion, in: Symposium (international) on Combustion, Elsevier, 1977, pp. 719-729.
[28] D. Spalding, Mixing and chemical reaction in steady confined turbulent flames, in: Symposium (International) on Combustion, Elsevier, 1971, pp. 649-657.
[29]  A. Yuen, G. Yeoh, V. Timchenko, S. Cheung, Barber, Importance of detailed chemical kinetics on combustion and  soot  modelling of ventilated and under-ventilated fires in compartment, International Journal of Heat and Mass Transfer, 96 (2016) 171-188.
[30] P.P.S. da Costa, Validation of a mathematical model for the simulation of loss of coolant accidents in nuclear power plants, (2016).
[31] S. Patankar, Numerical heat transfer and fluid flow ,CRC press, 1980.
[32] A.A. Fancello, Dynamic and turbulent premixed combustion using flamelet-generated manifold in openFOAM, BOXPress, 2014.
[33]  S. Tieszen, T. O’hern, R. Schefer, E. Weckman, T. Blanchat, Experimental study of the flow field in and around a one meter diameter methane fire, Combustion and Flame, 129(4) (2002) 378-391.