The effects of electrode divergence angle and mean gap velocity on the performance of gas-blown spark gap switches



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Texas Tech University


The effects of fluid velocity and electrode divergence angle on the performance of a gas-blown spark gap switch operating in a self-breakdown mode are presented. The switch was contained in a two-dimensional, axially blown, diverging wind tunnel with an aspect ratio of 40:1. The mean gap velocities, the mean flow velocities in the plane of the minimum separation point, ranged from 4 to 17 m/s. The divergence angles studied were 5.0, 7.5, and 10.0 degrees. The flushing gas used was instrument grade dry air ( < 10 ppm H20 ), and the electrode material was 304 stainless steel. High-speed interferograms were used to verify the data reduction program and to identify all events.

The relationship between the minimum mean gap velocity, Ūth, and divergence angle, 0, required for a predetermined failure rate was determined in this study. This relationship is of the form, Ūth = A*e-(b0)+B, which illustrates the importance of the divergence angle on the flow rate required for successful switch operation.