Improvement of a “mini” two-stage light-gas gun for hypervelocity impact experiments: Technical devices to accelerate and detect a “minute” projectile efficiently

Abstract

A gas-gun system was improved and optimized in order to obtain higher projectile velocity. The gas gun used in this study was a “mini” two-stage light-gas gun suitable for the acceleration of a “minute” projectile. As a major improvement in the mini gun, the high-pressure coupler was divided into two parts. One part was a generation section of the hot and high-pressure working gas by compression with a piston, and the other was a flow rate control section of the working gas. The mini gun, after installing the improved high-pressure coupler, showed an increase not only in the projectile velocity but also in the energy efficiency converting the combustion energy to the projectile kinetic energy, compared with the conventional mini gun. In the firing test using hydrogen as a working gas, a projectile velocity of 5.91km∕s was achieved by the use of the improved mini gun, as compared with a velocity of 4.70km∕s before the improvements were made. The modifications to the mini-gun system and their effects on the performance of the mini gun are discussed.