Study On Micro Scale Discharge Mode In Pin-to-Plan DBD

Dielectric barrier discharge (DBD), is a typical non-equilibrium AC gas discharge, and is an effective means of producing non-equilibrium plasma in atmospheric pressure, which has become one of the hot plasma of subjects. However, dielectric barrier discharge has a highly complex system and discharge phenomenon. The scale of discharge device is enlarged simply, that will drop the discharge performance. This thesis combines with "National Natural Science Foundation" (No.50877005), and focuses on the research of pin-to-plan electrode DBD in micro scale.The main DBD discharge mode in the industrial applications is micro-discharge, which is the discharge unit in the DBD. In order to observe the micro-discharge, the device of pin-to-plan DBD was schemed out. Discharge morphology of micro-discharge was collected used the method of CCD camera, the whole process of evolution of micro-discharge was validated in experiment. It was found that, as the role of the deposited charge, discharge channel curved in the discharge process of development. Three parameters were quoted for describing the space morphology of micro-streamer discharge. Applied voltage and the dielectric layer thickness have a greater influence to these three parameters than discharge gap.It was found, in the discharge gap of pin-to-plan DBD device, when the applied voltage reached a certain value, a new discharge mode which is similar to the low pressure glow discharge (we called it micro-glow discharge) was acquired, not only micro-discharge. The micro-glow discharge and micro-discharge happen in different discharge half-cycle when the applied voltage is higher. Discharge morphology of micro-glow discharge and low pressure glow discharge is very similar. The discharge current pulses of the micro-discharge are wide (25us), and only one in a discharge cycle. Lissajous graph also shows several charge transition. Thus, the micro-glow discharge is different discharge form.Additionally, numerical model of micro-discharge was established on the basis of diffusion-drift fluid model in this paper. Three kinds of particle, electron, positive and negative ions, were regarded in this numerical model, and Particle diffusion, drift, synthesis and decomposition process were also regarded. Boundary and initial conditions of continuity equation and Poisson equation were ascertained. Various factors in the value equation were identified too. That lay the foundation for future work of numerical simulation.