碩士生: 張家瑋
畢業年月: 2023年7月
論文名稱: 回流區特性對斜向噴流燃燒器中粉煤燃燒效率的影響分析 / Analysis of the effect of recirculation zone characteristics on the combustion efficiency of pulverized coal in inclined jet burner
中文摘要:
本研究提出結合雙斜向甲烷／空氣預混噴流與粉煤噴流的撞擊式燃燒器，期望實現潔淨高效燃燒。實驗以粒子圖像測速、氣體分析儀、熱電偶與掃描電鏡，探討預混當量比、氣體流速、偏轉角與粉煤／空氣流速的影響。兩股噴流撞擊後形成碰撞區與回流區：前者增強動量傳遞與混合，後者使粉煤滯留並發生熱解，大顆粒因熱應力破碎，釋出的甲烷與一氧化碳等揮發分在下游對衝火焰中燃燒。SEM證實顆粒因熱解而縮小，高溫更促進裂解與燃盡。提高甲烷／空氣流速與中心流速可顯著提升粉煤燃盡率，顯示此燃燒器能促進氣固混合並支持穩定潔淨燃燒。
英文摘要:
This thesis proposes an oblique jet impinging burner composed of two methane/air premixed jets and a pulverized coal jet for clean and efficient combustion. Particle image velocimetry, gas analysis, thermocouples, and SEM were used to examine the effects of equivalence ratio, gas velocity, deflection angle, and coal/air feed rate. The colliding jets form a collision zone that enhances momentum transfer and mixing, and a recirculation zone that holds coal particles long enough to pyrolyze; thermal stress fragments the particles and releases volatiles such as methane and carbon monoxide that burn in the downstream counterflow flame. SEM confirmed particle size reduction, and high temperature favored stronger decomposition and burnout. Raising the methane/air velocity and the central flow velocity significantly improved coal burnout, showing that the burner promotes gas-solid mixing and stable, clean combustion.
