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

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نشریه مهندسی مکانیک امیرکبیر
دوره 52، شماره 9
آذر 1399
صفحه 2425-2442

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