氩气氛围下微波辅助点火机理  

Mechanism of Microwave-Assisted Ignition in Argon Atmosphere

作　　者：王兆文[1] 刘超辉 吴慧珉 许景星 成晓北[1] Wang Zhaowen;Liu Chaohui;Wu Huimin;Xu Jingxing;Cheng Xiaobei(Department of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学能源与动力工程学院,湖北武汉430074

出　　处：《内燃机学报》2024年第2期114-123,共10页Transactions of Csice

基　　金：国家自然科学基金资助项目(51576083).

摘　　要：基于自行搭建的微波辅助点火(MAI)试验台架,引入高时间分辨率的电气诊断系统,对比了N_(2)氛围和Ar氛围对微波辅助点火核心发展的影响,并从微波等离子体形成和放电电流演变等方面探究了MAI点火核心发展的内在机制.结果表明:当量比为0.80时,N_(2)氛围和Ar氛围中的微波增强作用均与微波等离子体的强度明显相关,但二者等离子体生成特征存在明显区别,Ar氛围中微波等离子体的生成阈值更低.将Ar氛围的当量比降低至0.65时,微波等离子体的生成特征与当量比为0.80的Ar氛围中基本一致,与当量比为0.80的N_(2)氛围存在显著差异,故微波等离子体的生成特征主要由工质氛围决定.用电气诊断系统得到的微波辅助放电窗口能定量表征微波等离子体的强度,同时,微波等离子体强度与微波对点火核心的增强效果呈线性相关.最终明确了微波辅助点火存在两个作用窗口,分别是增强火花放电的微波辅助放电窗口和增强点火核心的微波辅助点火窗口,二者共同作用决定着微波增强的最终效果.The effects of N_(2) atmosphere and Ar atmosphere on the core development of microwave-assisted ignition(MAI)were comparatively studied on a self-built MAI experimental bench with a high time resolution electrical diagnosis system.From the origin of microwave plasma formation and discharge current evolution,the internal mechanism of MAI core development was explored.The result shows that,when the equivalent ratio is 0.80,the enhancement effect of microwave in N_(2) atmosphere and Ar atmosphere is significantly correlated with the intensity of microwave plasma.However,the plasma generation characteristics of the two atmospheres are significantly different,and the generation threshold of microwave plasma in Ar atmosphere is lower.When the equivalent ratio of Ar atmosphere is reduced to 0.65,the generation characteristics of microwave plasma are basically the same as that of Ar atmosphere with equivalent ratio of 0.80,but are significantly different from that of N_(2) atmosphere with equivalent ratio of 0.80.Therefore,the generation characteristics of microwave plasma are mainly determined by the working atmosphere.The microwave-assisted discharge window obtained by the electrical diagnostic system can quantitatively characterize the intensity of the microwave plasma.At the same time,the intensity of the microwave plasma is linearly related to the enhancement effect of the microwave on the ignition core.Finally,it is clarified that there are two effect windows for MAI,namely,the microwave-assisted discharge window for enhanced spark discharge and the microwave-assisted ignition window for enhanced ignition core,both of which work together to determine the ultimate effect of microwave enhancement.

关 键 词：微波辅助点火 氩气氛围 等离子体 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]