火焰速度是燃料的燃燒特性，火焰速度在應用上主要為燃燒室設計、紊流火焰之模擬參數、燃燒反應特性分析、防火研究等。本文利用實驗設計一封閉式之等壓直管火焰量測系統，量測甲烷/空氣混合氣體在不同壓力及不同燃料/空氣混合比下的火焰傳遞速度及焰面面積變化，並探討火焰在直管中的傳遞特性、拉伸速率及層流火焰速度。
實驗設備由擴散槽、蓄壓閥、氣動閘閥、內徑40cm 長150cm直管所組成的可在封閉系統下進行高壓環境的等壓量測；火焰通過直管同時以10組光電二極體，紀錄火焰訊號，並配合計時器計算火焰傳遞速度，再經由修正求得燃料之層流火焰速度。實驗觀察火焰傳遞速度受到管壁的熱傳效應、面積效應、熱幅射效應與點火能量影響，造成火焰在直管前端加速，在管中段時，則因面積效應與熱傳效應使得火焰減速，且因管壁熱散失使焰面呈拋物面狀。本實驗觀測之層流火焰速度是以拉伸速率近約零之火焰面積與傳遞速度計算得之。
在1大氣壓的環境下，甲烷的層流火焰速度隨當量比之變化趨勢和文獻相符合，但明顯較低。且甲烷火焰速度隨壓力提昇而明顯降低，分析顯示甲烷燃燒之反應階層(reaction orders)隨當量比提昇而漸驅於1，其火焰速度對壓力變化之敏感度較高。

Abstract
Laminar flame speed is a combustion property of fuel. Laminar flame speed was used in combustor design, parameter of turbulence simulation, analysis of chemical reaction of combustion, fire suppressants research. This thesis designed an open-open tube which can maintain constant pressure and close system to measure flame speed of CH4/air mixtures with different equilibrium rations (0.8-1.2) and different pressure (1,2,3,5,atm)at initial temperature 300k.and discuss about flame propagation speed and flame stretch rate in tube.
To reduce error of measuring laminar flame speed, we developed an open-open tube system to measure laminar flame speed. This system included pressure wave damper, pressure absorber, gate valve which were used to maintain system in constant pressure during flame propagating .and photodiode, data acquisition sub system, counter, which were used to calculate flame propagation speed By analyzing photodiode signal, we can assume flame surface in tube is concave, then estimated flame area and laminar flame speed.
Flame propagation speed would change by influence of heat conduction, thermal radiation, buoyancy effect .The experimental data showed the flame propagation speed was very fast in front of observed point. It because of ignition energy is too high so increased flame propagation speed. Flame in tube would be stretched and flame surface became concave because of Thermal effect and buoyancy effect. In order to accurately measure laminar flame speed.We chose observed point which flame stretch rate was zero to estimate flame area and laminar flame speed.
At 1atm the resulting laminar flame speed meet laminar flame speed presented in literatures. We could estimate reaction order by experiments data, compared with reaction order estimate by simulation data. Result showed practicability of experiment system.

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