Enhancing liquid jet erosion
AssigneeHydronautics, Incorporated
InventorVirgil E. Johnson, Jr.
Life of this patent
Estimating the term…
Abstract
Process and apparatus for enhancing the erosive intensity of a high velocity liquid jet when the jet is impacted against a surface for cutting, cleaning, drilling or otherwise acting on the surface. A preferred method comprises the steps of forming a high velocity liquid jet, oscillating the velocity of the jet at a preferred Strouhal number, and impinging the pulsed jet against a solid surface to be eroded. Typically the liquid jet is pulsed by oscillating the velocity of the jet mechanically or by hydrodynamic and acoustic interactions. The invention may be applied to enhance cavitation erosion in a cavitating liquid jet, or to modulate the velocity of a liquid jet exiting in a gas, causing it to form into discrete slugs, thereby producing an intermittent percussive effect.
Claims31
A method of eroding a solid surface with a high velocity liquid jet, comprising the steps of:
- (a) forming a high velocity liquid jet;
- (b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2;
- and
- (c) impinging the pulsed jet against the solid surface.
A method of eroding a submerged solid surface with a liquid jet, comprising the steps of:
- (a) forming a liquid jet by passing a liquid through a hydro-acoustic oscillator having a submerged nozzle;
- (b) oscillating the velocity of the jet at the resonant frequency of said oscillator, said frequency corresponding to a Strouhal number within the range of from about 0.2 to about 1.2;
- (c) amplifying the jet velocity oscillations by providing the exit nozzle with a contour adapted to provide feedback of the velocity oscillations in the jet to the oscillator;
- and
- (d) impinging the pulsed jet against the submerged solid surface.
A method of eroding a submerged solid surface with a liquid jet, comprising the steps of:
- (a) forming a liquid jet structured into discrete, spaced apart vortices by passing a liquid through a hydroacoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a first portion with a contraction contour followed by a substantially cylindrical portion having its upstream end adjacent to said first portion, the junction of said first portion and said cylindrical portion forming a sharp edge, said cylindrical portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow;
- (b) oscillating the velocity of the jet at the resonant frequency of said chamber, said frequency corresponding to a Strouhal number within the range of from about 0.2 to about 1.2;
- (c) amplifying the jet velocity oscillations by providing feedback of the velocity oscillations in the jet to the oscillator chamber;
- and
- (d) impinging the pulsed jet against the submerged solid surface.
A method of oscillating the instantaneous boundary pressure at a submerged surface, comprising the steps of:
- (a) forming a high velocity, submerged liquid jet;
- (b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the jet forms into discrete, spaced apart vortices;
- (c) impinging the discrete vortices against the submerged surface, whereby the instantaneous boundary pressure is reduced during each discrete time interval that one of the vortices passes adjacent said surface.
A method of removing the chips created at a submerged surface by a mechanical rotating roller bit drill, comprising the steps of:
- (a) contacting the submerged surface with said drill, whereby at least a portion of the surface is fragmented into chips;
- (b) forming a high velocity, submerged liquid jet;
- (c) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the jet forms into discrete, spaced apart vortices;
- and
- (d) impinging the discrete vortices against said portion of the surface.
Dependencies are inferred from the claim text.