烃类燃料的燃烧使火焰中含有带电粒子,因此通过外加电场可以实现对微小尺度下液体燃料的燃烧控制。采用液体乙醇为燃料,内径0.9 mm不锈钢管为喷管,外加高压直流电场,得到小尺度扩散火焰伏安特性曲线。将燃烧系统等效成电路模型,根据电路理论得到火焰等效电阻变化规律。产生的离子电流作为被调量,运用简单的经典PID闭环控制,实现了对火焰的控制。仿真结果表明,设计的控制系统具有较好的抗干扰能力,为微型燃烧器的控制和稳定运行提供理论指导和参考依据。
Charged particles in the flame produced by combustion of hydrocarbon fuels provided an alternative control option via external electric fields.The liquid ethanol was used as fuel.A stainless steel tube with an inner diameter of 0.9 mm was used as the nozzle and an external direct-current electric field was applied.The voltage-current characteristics of a small scale diffusion flames under the electric field were identified.The combustion system can be assumed as an equivalent circuit model.According to the theory of circuit,the change rules of flame equivalent resistance were obtained.The ion production was used as a sensor and a classical simple PID closed control method was used to adjust the flame.The simulation results showed that the system designed in present paper had well anti-jamming capability.The present study can supply some certain guidelines for the control and stable operation of microscale combustor.