Repetition Frequency Of The High-power Gas Spark Switch Theory And Experimental Research

In this paper, some theoretical and experimental researches of high-power repetitive gas spark switches are introduced. To find the ways to increase repetition rates and lifetime of the switches, mechanisms of two physical processes which determine repetition rates and lifetime of the switches ,dielectric recovery and electrode erosion, were studied in theory, and a serial of high-energy high-coulomb repetitive experiments were performed with two different three-electrode gas spark switches designed by ourselves.In the studying of the dielectric recovery mechanism, the dielectric process of high-power repetitive gas switches was analyzed theoretically, the conditions of full recovery of dielectric capability, and some qualitative results were obtained. Then, a dynamic mathematical model of the dielectric recovery process was made, and a group of equations ,including mass conservation equation, momentum conservation equation, energy conservation equation and state equation, were built. Also, a mathematical model of the dielectric recovery process of a axially-blown gas spark gap, and a group of simplified hydromechanical equations were made.The basic physical mechanisms of the electrode erosion process of high power gas switches were also studied. According to energy conservation equation and fusion and evaporation characteristics of electrode materials, a simplified one-dimension mathematical model was made and numerically solved by means of FDTD (finite - Difference Time-Domain). By the numerical results basic physical processes of electrode erosion are investigated, the relations between eroded volume of electrodes and some characteristic parameters of electrode materials such as heat conductance, specific heat, melting point, boiling point and so on were obtained, and erosion-resistant capabilities of copper, tungsten and aluminum were compared.With an experimental system built and two different switches designed by ourselves, a serial of high-energy high-coulomb repetitive experiments were performed at voltage up to 100kV, peak current up to 85kA, charge transfer up to about 0.6C per pulse, repetition rate up to 10Hz, and single shot energy up to 5kJ. These experimental results indicated that several factors such as gas velocity, electrode erosion, insulator envelope pollution and so on limited the repetitive operating capability of the switches.