The Measurement on Micro-Jet Impulse Based on Laser Interferometer Available to Purchase

In the paper the heterodyne laser vibrometer combined with torsion pendulum system is employed to measure contactless the oscillating velocity of the horizontal target struck by pulse hydrone micro-jet in the experimental platform, which has the feature of measuring precisely impulse (measurement error ≤ 0.618%). The oscillating velocities of pulse micro-jet from converging-diverging, converging and cylindrical nozzles striking on horizontal target are measured respectively in normal atmosphere, and the values of the impulses are calculated by employing the dynamic character equation of force acted by pulse micro-jet. The result of experiment show that the impulse of converging nozzle with the ratio of sectional area of exit to that of inlet (Aexit/Ainlet) being 0.1 is 65% of that of cylindrical nozzle, and is 26.8% of that of converging-diverging nozzle with the ratio of sectional area of throat to that of inlet (Athroat/Ainlet) being 0.1145. Converging-diverging nozzle has obvious gaining on the impulse of hydrone propellant.