点火器冷却气流对点火过程影响的实验研究

In order to improve the operational reliability and service life of the multi-channel plasma igniter，and solve the problem of ablation failure of igniter end face caused by the instantaneous high temperature triggered by the large discharge energy and the long-term high temperature of the working environment，a cooled multi-channel plasma igniter is designed and developed based on the embedded multi-channel plasma ignition gun and forced convection heat transfer in this paper. A single-head swirl spray basic combustion chamber experimental system is established，and an experimental study on the ignition characteristics of the cooled multi-channel plasma igniter was carried out. Using the CH* self-luminous signal diagnosis system combined with the numerical image processing method，the effects of the number of discharge channels，cooling airflow and incoming flow on the ignition process were analyzed，and the lean ignition boundary under different conditions was compared. The results show that the cooling airflow increases the lean ignition limit equivalence ratio and ignition delay time. Under the condition of 400SLM incoming flow and 50SLM cooling airflow，the ignition limit equivalence ratio of the multi-channel plasma igniter is 0.304，and the ignition delay time is 37.4ms，which are both larger than those without cooling airflow. Compared with the single-channel igniter，the multi-channel plasma igniter can significantly broaden the lean ignition boundary and is less affected by the cooling airflow. Under the condition of 400SLM incoming flow and no cooling airflow，the multi-channel plasma igniter can expand the ignition boundary by 3.2%，while the broadening effect reaches 3.7% with 50SLM cooling airflow.