Exploitation of Hypervelocity liquid jet generator by using Neumann effect

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High speed liquid jets have been intensively applied to the process of fuel sprays in diesel engines and also water jet cutting technology. However, their peak speed ranges up to 1 km/s. Today neither the method of generating high speed liquid jets nor its underatanding have not yet been technically well developed. Previously the chief investigator of this project has developed atechnology in which by using a single stage gas gun the impact of a flat headed high speed projectile of 1-2 km/s on a liquid container created high speed jets of 3-4 km/s. However, this method required a very elaborately designed non-reusable type nozzle so that it can never be practical. It is well known that in pyro-engineering a reverse cone shaped charge, once detonated, produced a very high speed debris jet along its axis, whose principle is called the von Neumann effect. High speed liquid jets can be readily produced by following the von Neumann effect when a reverse cone shaped water container was impin … More ged by a high speed flat headed piston. This project aims to simulate numerically the generation high speed liquid jets and based upon the numerical result to construct a compact facility which can generate high speed liquid jets as an extension of the von Neumann effect. Results obtained are summarized as following :(1) Numerical simulation revealed that the gain in jet speeds was over 50 % of piston speeds.(2) The apex angle of reverse cone shapes was approximately 22 degree and the resulting jet speed ranged from 3 to 6 km/s.(3) A single stage gas sun of 15 mm bore was manufactured which drove projectiles with muzzle speed of 0.6 to 1.5km/s for the amount of smokeless powder of 0.5 to 1.5 gr.(4) Holographic interferometric observations have been successfully carried out to visualize the formation and fragmentation of liquid jets.(5) The flight and fragmentation of liquid droplets have been clarified and their results revealed that it is technically possible to obtain a high speed water jet exceeding over 6 km/s. Less