Enhancing liquid jet erosion

Claim 2

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.

Claim 3

Apparatus as claimed in claim 1, wherein the oscillator comprises an organ-pipe oscillator.

Claim 4

Apparatus as claimed in claim 1, wherein the oscillator comprises a Helmholtz oscillator.

Claim 5

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.

Claim 6

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.

Claim 7

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°, 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.

Claim 8

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°, 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.

Claim 9

Apparatus as claimed in claim 5, wherein said imaginary surface is defined by the equation Y=As n X, whose origin is located in the plane extending through said junction at a distance from the axis of the nozzle equal to the contracted radius of the jet, wherein X and Y are the Cartesian coordinates and the Y axis passes through said origin and is normal to the axis of the nozzle, S is the critical Strouhal number, and A and n are constants determined by the fluid properties of the liquid.

Claim 10

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.

Claim 11

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.

Claim 12

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.

Claim 13

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.

Claim 14

Apparatus as claimed in claim 7, wherein the tangent to said curved portion of the exit nozzle at the junction of said curved portion and said frusto-conical portion defines the exit angle, measured in reference to the longitudinal centerline of the nozzle, and said exit angle is at least 30°, and wherein said imaginary surface is defined by the equation Y=As n X, whose origin is located in the plane extending through said junction at a distance from the axis of the nozzle equal to the contracted radius of the jet, wherein X and Y are the Cartesian coordinates and the Y axis passes through said origin and is normal to the axis of the nozzle, S is the critical Strouhal number, and A and n are constants determined by the fluid properties of the liquid.

Claim 15

Apparatus as claimed in claim 8, wherein said imaginary surface is defined by the equation Y=AS n X, whose origin is located in the plane extending through said sharp edge at a distance from the axis of the nozzle equal to the contracted radius of the jet, wherein X and Y are the Cartesian coordinates and the Y axis passes through said origin and is normal to the axis of the nozzle, S is the critical Strouhal number, and A and n are constants determined by the fluid properties of the liquid.

Claim 16

Apparatus as claimed in claim 10, wherein A=1.15 and n=3/2 for water, at a Reynolds number on the order of about 7×10 5 .

Claim 17

Apparatus as claimed in claim 8, wherein said curved surface is defined by a circular arc whose radius is determined by said two points of tangency.

Claim 18

Apparatus as claimed in claims 7 or 12, wherein the overall length of the organ-pipe oscillator chamber lies within the range of from about ##EQU38## to about (N/2)·(D/MS), where N is the resonant mode number, D is the diameter of the frusto-conical portion at its upstream end, M is the Mach number of the jet, and S is the Strouhal number, and wherein S is within the range of from about 0.3 to about 0.8.

Claim 19

Apparatus as claimed in claims 7 or 12, wherein at least two nozzles supplied from the same plenum are provided, at least one of said nozzles being larger than the other, and wherein the sizes of the nozzles are selected to supply a preselected total discharge, with the larger nozzle exciting a lower organ-pipe mode than the smaller nozzle.

Claim 20

Apparatus as claimed in claim 8, wherein the length of said substantially cylindrical portion is about 60% of the distance between said sharp edge and the point of intersection of the imaginary extension of said cylindrical portion with said imaginary surface.

Claim 21

Apparatus as claimed in claim 15, wherein the distance along said imaginary surface between the point of tangency of the curved surface with said imaginary surface and said point of intersection is equal to about 40% of the distance between said sharp edge and said point of intersection.

Claim 22

Apparatus as claimed in claim 8 or 16, wherein said curved surface extends beyond said point of tangency with said imaginary surface a distance equal to about 10% to about 20% of the diameter of the nozzle at said sharp edge.

Claim 23

Apparatus as claimed in claim 8, wherein the tangent to said contraction contour at said sharp edge defines an exit angle, measured in reference to the longitudinal centerline of the nozzle, said exit angle being less than about 30°, and wherein said sharp edge defines an abrupt discontinuity in slope, in the form of a step, whereby the diameter of said cylindrical portion is larger than the nozzle diameter at said sharp edge.

Claim 24

Apparatus as claimed in claims 7 or 8, wherein the resonant frequency of said chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.4 and the resonant mode number of the chamber is 1.

Claim 25

Apparatus as claimed in claims 7 or 8, wherein the value of the resonant mode number of the chamber is selected such that the Strouhal number is at its minimum value, provided it is not less than about 0.3.