Abstract Flame propagation behaviours in 40 nm titanium, aluminium and iron dust clouds were investigated by high-speed photography. 40 nm titanium, aluminium and iron dust flames were all characterized by discrete single glowing burning particles with smoothly spherical front. “Micro explosions” caused by the fragment ejection occurred in both 40 nm titanium and aluminium particles burning processes. At nano scales, the heat and mass transfer regimes were absolutely different with micro particles, which resulted in different propagation velocities. The average pulsating flame propagation velocities of 40 nm titanium, aluminium and iron dust clouds were 0.565 m/s, 0.189 m/s and 0.035 m/s, respectively. From SEM analysis, it was inferred that 40 nm titanium, aluminium and iron particles were burnt in liquid, gas, and solid-phase, respectively. From XPS analysis, it was found that N 2 played a significant role in titanium particles combustion. 40 nm titanium combustion products contained 43% TiO 2 (Ti 4 + ), 27% Ti 2 O 3 (Ti 3 + ), 21% TiO (Ti 2 + ) and 9% TiN (Ti 3 + ). While 40 nm aluminium combustion products just contained 100% Al 2 O 3 (Al 3 + ), and 40 nm iron combustion products contained 49% Fe 2 O 3 (Fe 3 + ), 26% Fe 3 O 4 (Fe 3 + /Fe 2 + ), 15% FeO (Fe 2 + ) and 10% iron nonoxides. Inerted by nitrogen for preventing nano‑titanium dust explosions was inadvisable.

中文翻译：

---

纳米金属粉尘爆炸中的火焰传播行为

摘要 通过高速摄影研究了40 nm钛、铝和铁粉尘云中的火焰传播行为。40 nm 钛、铝和铁粉尘火焰的特征都是离散的单个发光燃烧颗粒，具有光滑的球形前沿。40 nm 钛和铝颗粒燃烧过程中都发生了由碎片喷射引起的“微爆炸”。在纳米尺度上，微颗粒的传热和传质机制完全不同，这导致了不同的传播速度。40 nm 钛、铝和铁粉尘云的平均脉动火焰传播速度分别为 0.565 m/s、0.189 m/s 和 0.035 m/s。从 SEM 分析推断，40 nm 的钛、铝和铁颗粒分别在液相、气相和固相中燃烧。从XPS分析发现N 2 在钛颗粒燃烧中起重要作用。40nm钛燃烧产物包含43% TiO 2 (Ti 4 + )、27% Ti 2 O 3 (Ti 3 + )、21% TiO (Ti 2 + )和9% TiN (Ti 3 + )。而 40 nm 铝燃烧产物仅包含 100% Al 2 O 3 (Al 3 + )，而 40 nm 铁燃烧产物包含 49% Fe 2 O 3 (Fe 3 + )、26% Fe 3 O 4 (Fe 3 + / Fe 2 + )、15% FeO (Fe 2 + ) 和 10% 非氧化物铁。为防止纳米钛粉尘爆炸而用氮气惰性化是不可取的。40 nm 铁燃烧产物含有 49% Fe 2 O 3 (Fe 3 + )、26% Fe 3 O 4 (Fe 3 + /Fe 2 + )、15% FeO (Fe 2 + ) 和 10% 非氧化物铁。为防止纳米钛粉尘爆炸而用氮气惰性化是不可取的。40nm铁燃烧产物含有49% Fe 2 O 3 (Fe 3 + )、26% Fe 3 O 4 (Fe 3 + /Fe 2 + )、15% FeO (Fe 2 + )和10%非氧化铁。为防止纳米钛粉尘爆炸而用氮气惰性化是不可取的。