火災模擬器之實驗與數值分析

長久以來火場的災害造成人類重大損失，本研究利用根據計算流體動力學(CFD)模式所建構之火災動態模擬(FDS)程式來進行火災模擬探討；再輔以實際燃燒爐實驗之量測結果，將模擬與實驗之數據相互比照，以探討實際燃燒之過程。本研究以建構火災模擬器來模擬火災場景裡的三種火焰型態，在三種不同場景之燃燒模擬過程中，將對燃燒爐內的氣體成分、濃度、溫度和速度等參數之分布情形，以及與時間函數做資料的擷取和結果的探討。其後再個別將模擬與實驗的火燄分佈及溫度做對照，來加以評估模擬情境之可信度。模擬數據結果得知，火源所置的地點影響著區劃空間中溫度的擴散情形，燃燒過程中對於氣體的流動上亦會造成渦流的產生，並發現到渦流大都是因為熱氣流的上升再碰撞至障礙物、天花板或是冷熱氣流交替的關係而產生，且當流場氣流擾動能越大表示其燃氣混合效應越好，對於燃燒之情形更加有助焰之效果。在燃料、氧氣與一氧化碳量的計算裡發現到，於開放性空間自然對流下，無論何種燃燒場景下，由開始燃燒至5秒後其曲線變化便不再繼續增加或減少的趨勢，且到達至某定值後便會保持在於平穩的狀態上。模擬與實驗中的溫度曲線圖及火焰分佈的狀態關係可判定出，於天花板上的延燒情形下，對於在火場裡的人們危害性是最低的；所量測之溫度值，在整體性上其中V型駐焰器溫度平均誤差約為11℃或11.7%，長型燃氣出口溫度平均誤差約為9℃或8.03%，方型燃氣出口溫度平均誤差約為26℃或8.9%，就大區域的火災溫度測量上，此結果可算是相當吻合。本研究初步驗證火災模擬器火焰的可控制性與實驗過程的安全性，並確定此FDS可用於火災模擬器下的火災模擬，對於往後進步一的研究下，可依FDS先行模擬之結果來判斷實驗中可能遇到的困難及危害性，進而加以預防提高實驗之成功率與準確性。

關鍵字

FDS ；火災模擬器； V型駐焰器；熱釋放率

並列摘要

The occurrence of fire has always caused a great calamity to mankind. How to carry on the rescue in the fire scene, reduce the injury when the fire occurs, resist expansion of the scene of fire and prevent the occurrence of the fire, etc, are the key subjects that people concentrate for a long time. In this thesis, we use Computational Fluid Dynamic (CFD) software: Fire Dynamics Simulator (FDS) program to simulate the discussion, solving the numerical solution in Navier-Stokes equation. FDS can be used for establishing the conditions similar to fire scene and shows the situation of dynamic simulation. In this thesis, we regarded propane gas as single gas, and measure with three different kinds of gas exporting type and fire source places. In the course of burning simulation of three kinds of different scenes, we are going to discuss following parameters, such as gas composition, thickness, temperature and speed in the combustion furnace and verify the simulation and experiment. The result of simulation shows that the place which putting fire source could influence the diffusion situation of temperature in the space. We also found that the vortices created because of the rising of the hot air collide to the barrier and ceiling or exchange of cold and hot air. From the results of experiment and simulation, we found the average temperature difference were about 11℃ or 11.7% which measured in V-gutter flameholder, 9℃or 8.03% in gas burner and 26℃ or 8.9% in storage fire simulator. The result in simulation is consistence with experiment. This thesis verified the control of flameholder of fire simulator and safety of experiment process at first and confirmed that the FDS software could simulate the fire in fire simulator. We can use the FDS software to simulate the fire before experiment to increase the accuracy of experiment and reduce the cost of experiment.

並列關鍵字

FDS ； fire simulator ； V-gutter ； heat release rate

參考文獻

National Chung Hsing University, Vol. 9, No.1, pp.

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火災模擬器之實驗與數值分析

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