碩士生: 多亞立 Aris Purwanto
畢業年分: 2021年10月
論文名稱: 微米及鐵顆粒在甲烷/空氣預混火焰之微爆現象研究(中文) / Study of microexplosion mechanism of iron microparticles in premixed methane/air flames(英文)
中文摘要:
金屬顆粒高體積能量密度的特性，有利於添加至固體推進劑中以增加整體能量輸出，或在燃煤爐中用金屬顆粒代替煤粉；相較於氣態碳氫化合物火焰，金屬混合火焰具有更高的能量、更高的火焰溫度。本研究旨在探討鐵混合燃燒粒徑對金屬顆粒微爆炸的潛在影響。本實驗使用四種不同的粒徑：2-10μm、50μm、100μm和150μm。預混錐形甲烷-空氣火焰在固定化學計量的條件下，以不同的進料速率摻入鐵顆粒。關於顆粒微爆炸機制，則係氧化劑擴散至鐵顆粒中，並在薄殼中生成氧化鐵。然而，有限的氧在鐵顆粒表面發生異質反應，從而在鐵顆粒表面產生中間產物氧化鐵 (FeO)。氧化鐵的形成，促使鐵顆粒在燃燒過程中有閃爍和收縮的現象。隨後，本研究於實驗中添加一氧化碳 (CO)，使一氧化碳穿透至氧化物殼層內部，並與殼層內之四氧化三鐵 (Fe2O3) 反應。四氧化三鐵將產生氣泡，並促成五羰基鐵 (Fe(CO)5)的形成。在氣泡凝聚過程中，鐵顆粒會逐漸膨脹，終將形成空心的球形顆粒。然而，在某些特殊條件下，五羰基鐵可能會引起鐵顆粒的微爆炸。
英文摘要:
The high volumetric energy density of metal particles is advantageous for adding to solid propellants to increase overall energy output or for replacing coal dust in coal-fired furnaces. Compared to gaseous hydrocarbon flames, metal-mixed flames possess higher energy and higher flame temperatures. This study aims to investigate the potential impact of iron particle size on the micro-explosion of metal particles during combustion.
The experiment utilized four different particle sizes: 2-10 μm, 50 μm, 100 μm, and 150 μm. Iron particles were incorporated into a stoichiometrically fixed premixed methane-air conical flame at various feed rates. Regarding the micro-explosion mechanism of the particles, the oxidizer diffuses into the iron particles, forming iron oxide in a thin shell. However, limited oxygen undergoes heterogeneous reactions on the iron particle surface, generating intermediate iron oxide (FeO). The formation of iron oxide causes flickering and contraction of the iron particles during combustion. Subsequently, carbon monoxide (CO) was introduced in the experiment, allowing CO to penetrate the oxide shell and react with the ferric oxide (Fe₂O₃) inside the shell. This reaction produces bubbles and facilitates the formation of iron pentacarbonyl (Fe(CO)₅). During bubble coalescence, the iron particles gradually expand, eventually forming hollow spherical particles. However, under certain conditions, iron pentacarbonyl can trigger the micro-explosion of iron particles.
