تاثیر مدل احتراقی در پیش بینی رفتار آتش استخری و تنوره حرارتی حاصل از آن با روش شبیه‌سازی گردابه‌های بزرگ

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد / دانشگاه تربیت مدرس

2 دانشگاه تربیت مدرس

چکیده

در این مقاله به کمک روش شبیه‌سازی گردابه‌های بزرگ رفتار آتش استخری بزرگ‌ مقیاس با توان حرارتی 14 و 45 کیلووات برای سوخت متان مورد بررسی قرارگرفته است. به‌منظور بررسی کارایی مدل‏ های احتراقی مختلف در مدل‌سازی آتش استخری، دو مدل احتراقی اضمحلال گردابه و شیمی بسیار سریع با مدل زیرشبکه یک‌-معادله ‏ای و سینتیک یک‌-‌مرحله‌ای مورد ارزیابی قرارگرفته شده است. نتایج به‌دست‌آمده از شبیه‌سازی با نتایج تجربی مطابقت خوبی داشته و میانگین دمایی و سرعت برای سه ناحیه شعله پایدار، متناوب و تنوره حرارتی ارزیابی شده است. با بررسی دما و سرعت شعله با نتایج تجربی مدل احتراقی اضمحلال گردابه، مدل مناسب‌تری در پیش‏بینی میدان سرعت و توزیع دما است. علاوه بر آن با استفاده از تحلیل فرکانسی بر روی نتایج دما و سرعت، رفتار گذرای آتش مورد بررسی قرار گرفت. نتایج نشان می‌دهد برای هندسه مورد بررسی فرکانس غالب برای دما و سرعت برابر شده و مقدار 2.75 هرتز بوده است. علاوه بر آن منحنی آبشار انرژی برای هندسه مورد بررسی استخراج شد که نشان از دقت شبیه‌سازی گردابه-های بزرگ استفاده‌شده در تعیین رفتار آتش وتنوره حرارتی آن است.

کلیدواژه‌ها


عنوان مقاله [English]

Effects of combustion model in predicting pool fire and fire plum behaviors using a large eddy simulation method

نویسندگان [English]

  • Mohammadhossein Jafari 1
  • Hadi Pasdarshahri 2
1 MSc Student / Tarbiat Modares University
2 Faculty of Mechanical Engineering/ Tarbiat Modares University
چکیده [English]

In this paper, methane pool fire and fire plumes with two heat release rates of 14 and 45 kW are simulated using Large-Eddy Simulation (LES) method. In order to investigate the accuracy of various combustion models, two combustion models of Eddy Dissipation Model (EDM) and Infinity Fast Chemistry (IFC) have been evaluated with a one-equation sub-grid scale model. The simulated results are in a good agreement with experimental measurements, and show the scaling relations of mean temperature and velocity in each pool fire region including stable flame, intermittent and plume. Results indicate that, EDM combustion model have a better prediction of mean velocity and temperature while it have more computational time. In addition, by incorporating Fast Fourier Transform (FFT) analysis on the transient results of temperature and velocity, the prevailing frequency for the temperature and velocity is equal which is 2.75 Hz for the current case. Moreover, energy cascade of eddies shows the accuracy of the LES in predicting pool fire dynamic.

کلیدواژه‌ها [English]

  • Large Eddy Simulation
  • Pool fire
  • Eddy dissipation model
  • Infinity Fast Chemistry
  • One-equation sub-grid scale model
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