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.
Claims20
Apparatus for producing a pulsed liquid jet exiting through an exit nozzle for eroding a solid surface, comprising:
- (a) means for forming a high velocity liquid jet;
- (b) acoustic-hydrodynamic oscillator means for oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2;
- and
- (c) means for amplifying the jet velocity oscilations, said means for amplifying said oscillations including said exit nozzle, wherein the internal contour of said exit nozzle is adapted to provide feedback of the velocity oscillations in the jet to said oscillator means.
Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising:
- (a) a liquid jet nozzle for discharging a liquid jet, said liquid jet nozzle having a housing for receiving a liquid, said housing having an interior chamber contracting to a narrower outlet orifice;
- (b) a Helmholtz oscillator chamber situated in tandem with the liquid jet nozzle for oscillating the liquid jet at a Strouhal number within the range of from about 0.2 to 1.2, said outlet orifice of the liquid jet nozzle comprising the inlet to the Helmholtz oscillator chamber and said Helmholtz oscillator chamber having a discharge orifice;
- and
- (c) a diffusion chamber situated in tandem with the Helmholtz oscillator chamber, said discharge orifice of the Helmholtz oscillator chamber comprising the inlet to the diffuser chamber, said diffusion chamber contacting to a narrower jet-forming orifice and smoothing the inflow to the jet-forming orifice.
Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comrising:
- a hydro-acoustic organ pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a portion with a curved contour followed by a portion with a substantially straight contour, said straight contour 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, the tangent to said curved portion at the junction of said curved portion and said straight portion defining an exit angle, measured in reference to the longitudinal centerline of the nozzle, said exit angle being less than about 30.degree., wherein the junction of said curved portion and said straight portion defines an abrupt discontinuity in slope, in the form of a step, said step being sufficiently large and said straight contour portion extending for a sufficient length to provide feedback of the velocity oscillations in the jet to the oscillator chamber.
Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising:
- a hydro-acoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a portion with a curved contour followed by a substantially frusto-conical portion having its upstream end adjacent to said curved portion, the junction of said curved portion and said frusto-conical portion forming sharp edge, said frusto-conical 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, said edge being formed sufficiently sharp and said frusto-conical portion extending sufficiently long to provided feedback of the velocity oscillations in the jet to the oscillator chamber, wherein the resonant frequency of the chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.8.
Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising:
- a hydro-acoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a first portion having 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 being followed immediately by a curved surface tangent to the downstream end of said cylindrical portion and further tangent to an imaginary surfac defining the outer envelope of the developing ring vortex flow, wherein said sharp edge, said cylindrical portion and said curved surface are adapted to provide feedback of the velocity oscillations in the jet to the oscillator chamber, and wherein the resonant frequency of the chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.8.
Dependencies are inferred from the claim text.