Volumetric Image Analysis Of Pulsed Non-Thermal Plasma Produced By Microwave

Abstract

We have been developing microwave pulsed mode ignition system using 2.45 GHz microwaves. This technology has shown improvements in the lean combustion limit and fuel efficiency using a real engine with propane using a microwave discharged igniter (MDI). However, the MDI’s expensive parts are a major drawback when compared to common igniters. For practicality, we shifted to a more economical flat spiral igniter to generate plasma enabling stable and sustained non-equilibrium plasma in the atmosphere. Incorporating semiconductor elements, we miniaturized the microwave generator system, enhancing compactness and increasing its efficiency. Initial plasma was generated by the partial energy from the microwaves (1 mJ) and the sustained plasma was maintained in the atmosphere by the rest of the microwave’s energy. We varied long to short-pulsed modes, changed microwave pulse widths, increasing repetition rates which affecting plasma volume and stability. Our findings highlight the significance of microwave input patterns and the transition from thermal to non-equilibrium plasma. Future discussions should focus on the ignition mechanisms of various fuels and the transition from plasma source to initialization region. Our work contributes to the understanding and practical application of non-thermal plasma in combustion systems.