本文以CHEMKIN PRO OPPDIF Package耦合聖地牙哥反應機制以甲烷、甲烷/一氧化碳/氫氣混合燃料之預混火焰進行一維對沖流燃燒下，黏性消散、熱傳導、質量擴散與化學可用能損失分析，並詳細探討各化學反應所產生之可用能損失。最後建立火焰厚度與總可用能損失之經驗公式與層流火焰速度及化學反應所產生之可用能損失關係。藉由改變初始條件可發現，當氣體初始溫度上升，熱傳導所產生之可用能損失降低，化學反應所產生之可用能損失提升，總可用能損失呈現上升趨勢。當環境壓力提升，質量擴散所產生之可用能損失隨著氣體密度上升而有明顯上升。貧油、化學當量及富油燃燒下隨拉伸率提升會有不同現象，貧油燃燒下，質量擴散與熱傳導產生之可用能損失皆隨拉伸率上升而上升；化學當量下，質量擴散可用能損失下降，熱傳導產生之可用能損失仍維持上升；富油燃燒下，兩種效應產生之可用能損失皆隨拉伸率提升而下降。但不變的是，化學反應所產生之可用能損失在三種情形下皆隨拉伸率上升而下降。目前對此之推測結果為因拉伸率提升造成不完全燃燒所產生之一氧化碳上升緣故。不論一氧化碳佔燃料比、環境壓力與氣體初始溫度為何，R49（CH3+O<=>CH2O+H）及R1（H+O2<=>OH+O）總產生相當大的可用能損失，R33（HCO+O2<=>CO+HO2）好發於甲烷佔比較低的情形。提升一氧化碳燃料比例，不見得代表與一氧化碳有關之化學反應會產生較大的可用能損失。藉由了解燃燒過程可用能損失，給予未來可用能應用及永續能源初步架構。

The irreversibility induced by viscous dissipation, mass diffusion, heat conduction and chemical reaction in CH4/CO/H2/air flame was studied using the 1-D counterflow flame numerical model coupled with the San Diego mechanism. The irreversibility caused by mass diffusion increased because of the increased gas density; the irreversibility caused by heat conduction decreased due to the increased initial gas temperature. The effect of strain rate in irreversibility generation differed from different equivalence ratio. For fuel-lean and stochiometric cases, the irreversibility caused by heat conduction always increased along increasing strain rate. However, for fuel-rich one, the irreversibility caused by heat conduction and mass diffusion usually decreased with rising strain rate. The only common characteristic was that the chemical-induced irreversibility was inversely proportional to strain rate regardless of the equivalence ratio. Irreversibility caused by chemical reaction was also studied. R49（CH3+O<=>CH2O+H） and R1（H+O2<=>OH+O） generated considerable irreversibility in all conditions. The irreversibility caused by each chemical reaction should not only consider the reaction rate but ponder the chemical potential. Finally, two empirical formulas were proposed in the present study. The overall total irreversibility can be estimated based on the flame thickness, and the chemical-induced irreversibility can be obtained according to the flame velocity.

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