高温下正十二烷喷雾及燃烧数值模拟研究

耦合RANS湍流模型、KH-RT破碎模型及SAGE燃烧模型,运用CFD数值模拟平台,对正十二烷在高温定容状态下的喷雾及燃烧现象进行研究。首先进行喷雾模型的标定与验证,确定了适合模拟的最小网格尺寸,然后分析若干边界条件对于正十二烷喷雾着火的影响规律。结果表明,环境压力对正十二烷喷雾尖端平均推进速率的影响程度不大;随着环境温度的升高,正十二烷喷雾的气相贯穿距不断增大,液相贯穿距呈现下降趋势,但变化并不明显;随着环境温度、环境氧浓度的升高,正十二烷喷雾滞燃期在不断地缩短,着火位置越来越靠近喷嘴。

Numerical simulation of n-dodecane spray and combustion at high temperature

Coupled with RANS turbulence model, KH-RT break-up model and SAGE combustion model, CFD numerical simulation platform was used to study the spray and combustion of n-dodecane at high temperatures and constant volume. Firstly, the spray model was calibrated and verified to determine the minimum mesh size suitable for simulation. Then the influences of several boundary conditions on n-dodecane spray and ignition were analyzed. The results show that ambient pressure has slight effect on the average advancing velocity of n-dodecane spray tip. With the rise in ambient temperature, the gas penetration length of n-dodecane spray increases, while its liquid penetration length decreases even though the change is not obvious. As the ambient temperature and oxygen concentration increase, ignition delay period of n-dodecane spray is continuously shortened, and the ignition location is closer and closer to the nozzle.