Deflection composite cavitation nozzle for water jet surface treatment

Abstract

The invention discloses a deflection composite cavitation nozzle for water jet surface treatment, and relates to the technical field of cavitation jet nozzles and jet surface treatment.The deflection composite cavitation nozzle comprises a nozzle inner pipe, a nozzle outer pipe and a deflection piece, the nozzle outer pipe is arranged outside the nozzle inner pipe in a sleeving mode, and a common flow cavity is formed between the nozzle outer pipe and the nozzle inner pipe; an inner cavity of the nozzle inner pipe is a high-pressure water flow channel, a high-pressure water flow inlet is formed in one end of the high-pressure water flow channel, the other end of the high-pressure water flow channel is blocked by a deflection piece, and a scaling outlet is formed in the position, close to the deflection piece, of the high-pressure water flow channel in the radial direction and communicated with the co-flow cavity. A high-pressure water and low-pressure water co-flow area is formed in the space between the scaling outlet and the outer nozzle outlet, and a low-pressure water flow inlet communicated with the co-flow cavity is formed in the side wall, away from the outer nozzle outlet, of the nozzle outer pipe. The cavitation rate can be greatly improved, the cavitation effect is better, and the treatment effect of cavitation jet flow is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cavitation jet nozzles and jet surface treatment, in particular to a deflection composite cavitation nozzle for water jet surface treatment. Background Art

[0002] In 2000, Soyama of Tohoku University in Japan first proposed the concept of cavitation water jet shot peening, and used this technology to significantly improve the fatigue strength of the alloy. The basic principle is that under the drive of the incident pressure, the water flow forms a high-speed jet with cavitation after passing through the cavitation nozzle, and shears with the static water body in the external flow field to form a low-pressure vortex structure. When the pressure is lower than the saturated vapor pressure of the liquid, a large number of cavitation nuclei sucked into the vortex structure become bubbles after primary birth and development. The bubbles move downstream with the high-speed jet to form a cavitation cloud. When the pressure around the cavitation cloud is restored, the cavitation group will collapse in a concentrated manner and impact the surface of the sample at a very high speed, changing the surface properties of the metal material. Compared with traditional mechanical shot peening, cavitation water jet shot peening has higher accessibility when processing confined structures and less improvement in the surface roughness of the material. Therefore, it has attracted the attention of many scholars at home and abroad in recent years. In addition, the structure and size of the cavitation nozzle have an important influence on the cavitation effect. At present, the shear type and oscillation type nozzles have better effects. The shearing nozzle uses the shear layer formed by high-speed fluid and low-speed fluid to produce cavitation. The oscillating cavitation nozzle uses resonance to produce cavitation by selecting the appropriate nozzle size to make the standing wave frequency generated by the high-pressure jet consistent with the natural frequency in the resonant cavity.

[0003] Deflected nozzles are mainly used for surface treatment in narrow corners and deep grooves. However, compared with other shearing nozzles, the shearing effect of deflected nozzles on the jet is weaker, making it difficult for high-speed jets to form shear layers and vortices. When used for surface treatment, the cavitation effect is poor, and cavitation collapse cannot be used to achieve an ideal treatment effect on the material surface. Therefore, a deflected composite cavitation nozzle is designed to increase its cavitation rate to achieve a better surface treatment effect. Summary of the invention

[0004] The purpose of the present invention is to provide a deflected composite cavitation nozzle for water jet surface treatment to solve the problems existing in the above-mentioned prior art, which can greatly improve the cavitation rate, make the cavitation effect better, and improve the treatment effect of the cavitation jet.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a deflected composite cavitation nozzle for water jet surface treatment, comprising a nozzle inner tube, a nozzle outer tube and a deflection member, wherein the nozzle outer tube is sleeved outside the nozzle inner tube, a co-flow cavity is formed between the nozzle outer tube and the nozzle inner tube, the inner cavity of the nozzle inner tube is a high-pressure water flow channel, a high-pressure water flow inlet is arranged at one end of the high-pressure water flow channel, and the other end is blocked by the deflection member, a zoom outlet is radially arranged near the deflection member on the high-pressure water flow channel, the zoom outlet is connected to the co-flow cavity, an outer nozzle outlet directly opposite to the zoom outlet is arranged on the side wall of the nozzle outer tube, the space between the zoom outlet and the outer nozzle outlet forms a co-flow area of ​​high-pressure water and low-pressure water, and a low-pressure water flow inlet connected to the co-flow cavity is arranged on the side wall of the nozzle outer tube away from the outer nozzle outlet.

[0007] Preferably, the nozzle inner tube is connected to the nozzle outer tube by a snap-fit ​​connection.

[0008] Preferably, two low-pressure water flow inlets are provided, and the two low-pressure water flow inlets are symmetrically arranged on both sides of the nozzle outer tube.

[0009] Preferably, the axis of the low-pressure water flow inlet is perpendicular to the axis of the nozzle inner tube.

[0010] Preferably, the low-pressure water flow inlet is arranged at a distance of 4 to 5 mm from the end surface of the nozzle outer tube away from the outer nozzle outlet.

[0011] Preferably, the convergent and multi-diameter outlet comprises a contraction section, a constant diameter section and a flare section which are arranged in sequence, the contraction section is connected to the high-pressure water flow channel, and the flare section is connected to the common flow cavity.

[0012] Preferably, the inlet diameter of the contraction section is 1.54 mm, and the contraction angle is 20°; the length of the equal diameter section is 1.5 mm, and the diameter is 1 mm; the length of the expansion section is 1.27 mm, and the expansion angle is 40° to 60°.

[0013] Preferably, the convergent outlet is arranged at a distance of 4 to 5 mm from the end surface of the nozzle inner tube on which the deflector is mounted.

[0014] Preferably, the inner diameter of the nozzle outer tube is 1-2 mm larger than the outer diameter of the nozzle inner tube, and the nozzle outer tube and the nozzle inner tube are coaxially arranged.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] The deflected composite cavitation nozzle for water jet surface treatment provided by the present invention provides a zoom structure (zoom outlet) at the outlet section of the inner tube of the nozzle, so that the high-speed jet has a stronger shearing effect, which can effectively enhance the cavitation effect generated after the jet is deflected. In addition, the low-pressure water jet enters the co-flow channel from the low-pressure water flow inlet of the outer tube of the nozzle, and finally meets the high-pressure water jet ejected from the zoom outlet. The two fluids with different flow rates form shear-type cavitation, which further promotes the growth of cavitation bubbles, increases the amount of bubbles transported to the impact surface, enhances the treatment effect of the cavitation jet, and maximizes the cavitation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic structural diagram of a deflected composite cavitation nozzle for water jet surface treatment in an embodiment of the present invention;

[0019] Figure 2 It is a front view of a deflected composite cavitation nozzle for water jet surface treatment in an embodiment of the present invention;

[0020] Figure 3 for Figure 2 Middle AA section view;

[0021] Figure 4 for Figure 2 Middle BB section view;

[0022] Figure 5 It is a velocity cloud diagram of a composite cavitation nozzle in an embodiment of the present invention;

[0023] Figure 6 This is a cavitation volume cloud diagram of the composite cavitation nozzle in an embodiment of the present invention.

[0024] In the figure: 1-nozzle inner tube, 2-nozzle outer tube, 3-deflection member, 4-co-flow chamber, 5-high-pressure water flow channel, 6-high-pressure water flow inlet, 7-zoom outlet, 8-outer nozzle outlet, 9-co-flow area, 10-low-pressure water flow inlet, 11-snap buckle. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a deflected composite cavitation nozzle for water jet surface treatment to solve the problems existing in the prior art, which can greatly improve the cavitation rate, make the cavitation effect better, and improve the treatment effect of the cavitation jet.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1-Figure 4 As shown, the present embodiment provides a deflected composite cavitation nozzle for water jet surface treatment, comprising a nozzle inner tube 1, a nozzle outer tube 2 and a deflection member 3, the nozzle outer tube 2 is sleeved outside the nozzle inner tube 1, a co-flow cavity 4 is formed between the nozzle outer tube 2 and the nozzle inner tube 1, the inner cavity of the nozzle inner tube 1 is a high-pressure water flow channel 5, a high-pressure water flow inlet 6 is arranged at one end of the high-pressure water flow channel 5, and the other end is blocked by the deflection member 3, a zoom outlet 7 is radially arranged near the deflection member 3 of the high-pressure water flow channel 5, the zoom outlet 7 is connected to the co-flow cavity 4, an outer nozzle outlet 8 is arranged on the side wall of the nozzle outer tube 2 opposite to the zoom outlet 7, the space between the zoom outlet 7 and the outer nozzle outlet 8 forms a co-flow area 9 of high-pressure water and low-pressure water, and a low-pressure water flow inlet 10 connected to the co-flow cavity 4 is arranged on the side wall of the nozzle outer tube 2 away from the outer nozzle outlet 8.

[0029] High-pressure water is injected into the nozzle inner tube 1 from the high-pressure water flow inlet 6, and the high-speed jet is deflected by the deflection member 3 at the bottom of the nozzle inner tube 1 to form a shear layer and produce cavitation. The cavitation jet formed by the deflection member 3 enters the internal zoom outlet 7. The zoom structure is used to make the high-speed jet have a stronger shear effect, which can effectively enhance the cavitation effect produced after the jet is deflected, so that the cavitation effect is strengthened. At the same time, low-pressure water flows from the low-pressure water flow inlet 10 into the co-flow cavity 4 between the nozzle outer tube 2 and the nozzle inner tube 1, and meets the high-pressure cavitation jet ejected from the zoom outlet 7 to form a high- and low-speed flow shear zone. The high- and low-speed jets form shear-type cavitation in the co-flow zone 9, which further promotes the growth of cavitation bubbles, greatly improves the cavitation rate, increases the amount of bubbles transported to the impact surface, and improves the treatment effect of the cavitation jet. The sample to be treated is placed downstream of the outer nozzle outlet 8 for treatment.

[0030] In this embodiment, the nozzle inner tube 1 and the nozzle outer tube 2 are connected via a buckle 11 .

[0031] In this embodiment, two low-pressure water inlets 10 are provided, and the two low-pressure water inlets 10 are symmetrically arranged on both sides of the nozzle outer tube 2. The axis of the low-pressure water inlet 10 is perpendicular to the axis of the nozzle inner tube 1. The low-pressure water inlet 10 is arranged at a distance of 4 to 5 mm from the end surface of the nozzle outer tube 2 away from the outer nozzle outlet 8.

[0032] In this embodiment, the zoom outlet 7 includes a shrinking section, a constant diameter section and a flaring section arranged in sequence, the shrinking section is connected to the high-pressure water flow channel 5, and the flaring section is connected to the common flow cavity 4. The inlet end diameter of the shrinking section is 1.54 mm, and the shrinking angle is 20°; the length of the constant diameter section is 1.5 mm, and the diameter is 1 mm; the length of the flaring section is 1.27 mm, and the expansion angle is 40° to 60°.

[0033] In this embodiment, the convergent outlet 7 is arranged at a distance of 4 to 5 mm from the end surface of the nozzle inner tube 1 on which the deflection member 3 is installed.

[0034] In this embodiment, the inner diameter of the nozzle outer tube 2 is 1-2 mm larger than the outer diameter of the nozzle inner tube 1 , and the nozzle outer tube 2 and the nozzle inner tube 1 are coaxially arranged.

[0035] In order to verify the feasibility of the composite cavitation nozzle of the present invention, flow field simulation and cavitation behavior simulation of the composite cavitation nozzle of this embodiment were performed based on the Mixture model and ZGB model of ANSYS FLUENT software.

[0036] Firstly, the composite cavitation nozzle model is meshed by ANSYS Meshing; secondly, the parameters are set by FLUENT. The pressure of the high-pressure water inlet 6 is set to 40MPa, and the pressure of the low-pressure water inlet 10 on both sides is set to 0.5MPa.

[0037] The speed cloud diagram of the simulation results is as follows Figure 5 As shown, the maximum velocity occurs in the internal convergent outlet 7, which can reach 328 m / s. After flowing out of the convergent outlet 7, there is a certain loss in velocity, and the maximum velocity is about 290 m / s.

[0038] The simulation results of the cavitation volume cloud diagram are as follows Figure 6 As shown, the maximum cavitation volume fraction is 0.978, the cavitation effect is obvious, and the maximum action distance can reach 40 mm.

[0039] Combined with the simulation results, it can be explained that the deflected composite cavitation jet nozzle of the embodiment of the present invention can effectively improve the cavitation rate by utilizing the co-flow cavitation energy. At the same time, the zoom outlet 7 of the nozzle inner tube 1 can effectively enhance the cavitation effect and improve the cavitation jet treatment effect.

[0040] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A deflected composite cavitation nozzle for water jet surface treatment, characterized in that: The utility model comprises a nozzle inner tube, a nozzle outer tube and a deflection member, wherein the nozzle outer tube is sleeved outside the nozzle inner tube, and a co-flow cavity is formed between the nozzle outer tube and the nozzle inner tube, the inner cavity of the nozzle inner tube is a high-pressure water flow channel, a high-pressure water flow inlet is arranged at one end of the high-pressure water flow channel, and the other end is blocked by the deflection member, a zoom outlet is radially arranged near the deflection member on the high-pressure water flow channel, and the zoom outlet is connected to the co-flow cavity, an outer nozzle outlet directly opposite to the zoom outlet is arranged on the side wall of the nozzle outer tube, and the space between the zoom outlet and the outer nozzle outlet forms a co-flow area of ​​high-pressure water and low-pressure water, and a low-pressure water flow inlet connected to the co-flow cavity is arranged on the side wall of the nozzle outer tube away from the outer nozzle outlet.

2. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The nozzle inner tube is connected to the nozzle outer tube via a buckle.

3. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The low-pressure water flow inlets are provided with two, and the two low-pressure water flow inlets are symmetrically arranged on both sides of the nozzle outer tube.

4. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The axis of the low-pressure water flow inlet is perpendicular to the axis of the nozzle inner tube.

5. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The low-pressure water flow inlet is arranged at a distance of 4 to 5 mm from the end surface of the nozzle outer tube away from the outer nozzle outlet.

6. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The convergent and contracting outlet includes a shrinking section, a constant diameter section and a flaring section which are arranged in sequence, the shrinking section is connected to the high-pressure water flow channel, and the flaring section is connected to the common flow cavity.

7. The deflected composite cavitation nozzle for water jet surface treatment according to claim 6, characterized in that: The inlet end diameter of the shrinking section is 1.54 mm, and the shrinkage angle is 20°; the length of the equal diameter section is 1.5 mm, and the diameter is 1 mm; the length of the expanding section is 1.27 mm, and the expansion angle is 40° to 60°.

8. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The convergent outlet is arranged at a distance of 4 to 5 mm from the end surface of the nozzle inner tube on which the deflection member is installed.

9. The deflected composite cavitation nozzle for water jet surface treatment according to claim 1, characterized in that: The inner diameter of the nozzle outer tube is 1 to 2 mm larger than the outer diameter of the nozzle inner tube, and the nozzle outer tube and the nozzle inner tube are coaxially arranged.

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