Detailed numerical simulations of the multistage self-ignition process of n-heptane, isolated droplets and their verification by comparison with microgravity experiments

摘要: Detailed understanding of the basic physical and chemical processes self-ignition phenomena for technical fuel sprays is required many combustion applications. Because single droplets as elements allow study fundamental ignition behavior, this work focuses on multistage behavior Φ 0.7 mm n -heptane in air. The investigated ambient conditions are temperatures from 580 to 1000 K pressures 0.3 1 MPa. A substantial model developed detailed numerical simulation. reaction mechanism consists a 62-step kinetic with special consideration low-temperature branch. program was validated by comparison results microgravity experiments at Drop Tower Bremen, which clarification process free natural convection. Cool flame hot appearances were obtained non-intrusive interferometric measurement well-tested experimental setup. calculated delays resulting temperature gradient criteria, respectively, compared these results. Furthermore, cool measured K-type thermocouple 25 μ m place its appearance also simulations. quantitative good agreement first total well could be achieved. With model, analyzed, criteria employed measurement, gradient, confirmed.