本研究採用數值模擬方法，探討甲烷預混二甲醚於對稱對沖流預混火焰中的燃燒行為，利用CHEMKIN-PRO軟體建立一維對沖流火焰模型，在常壓、常溫條件下，系統性分析不同二甲醚體積比例（30%、50%、80%）及不同當量比（ϕ = 0.8、1.0、1.2）對火焰結構與燃燒特性之影響，研究內容包含火焰溫度分佈、主要與次要物種濃度、中間產物生成率、反應路徑分析、熱釋放率以及靈敏度分析，以深入探討混合燃料之燃燒機制。
數值結果顯示，隨著二甲醚比例增加，火焰反應性明顯提升，峰值火焰溫度上升，反應區域趨於集中，且關鍵自由基（H、O、OH）之生成量顯著增加，有效促進甲烷之氧化反應，進而提升火焰穩定性與抗拉伸能力；在當量比為1.0時，火焰呈現最佳燃燒表現，而在貧燃與富燃條件下，燃燒特性則受到自由基生成行為及中間產物反應路徑變化之影響。反應路徑與靈敏度分析結果進一步顯示，二甲醚可透過其快速分解所產生之中間物種，強化甲烷燃燒反應鏈，對整體熱釋放與燃燒效率具有關鍵影響。

This study presents a numerical investigation of opposed-flow premixed flames of methane (CH₄) blended with dimethyl ether (DME) under atmospheric pressure. With increasing concerns regarding carbon emissions and environmental sustainability, alternative clean fuels and fuel blending strategies have received growing attention. Dimethyl ether is regarded as a promising alternative fuel due to its high cetane number, oxygenated molecular structure, soot-free combustion characteristics, and compatibility with existing liquefied petroleum gas infrastructure. Methane, the primary component of natural gas, exhibits relatively clean combustion but suffers from low flame speed and limited flammability under stretched conditions. The present study aims to examine whether premixing DME with methane can enhance flame stability and combustion performance.
Numerical simulations were performed using the CHEMKIN-PRO software with an opposed-flow premixed flame configuration. Flame structures, temperature distributions, major and minor species concentrations, reaction pathways, heat release rates, and sensitivity coefficients were systematically analyzed under various equivalence ratios and fuel blending ratios. The results indicate that increasing the DME fraction significantly enhances flame reactivity, raises peak flame temperature, accelerates radical production, and improves resistance to flame stretch. These findings provide mechanistic insights into methane–DME blended combustion and support the potential application of DME as a combustion enhancer in clean energy systems.

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