CN115138494B - Device and method for actively controlling cavitation water jet to strengthen inner surface of micro hole - Google Patents
Device and method for actively controlling cavitation water jet to strengthen inner surface of micro hole Download PDFInfo
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- CN115138494B CN115138494B CN202210972594.7A CN202210972594A CN115138494B CN 115138494 B CN115138494 B CN 115138494B CN 202210972594 A CN202210972594 A CN 202210972594A CN 115138494 B CN115138494 B CN 115138494B
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 114
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 5
- 238000007789 sealing Methods 0.000 claims abstract description 4
- 238000005728 strengthening Methods 0.000 claims description 32
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- 230000002035 prolonged effect Effects 0.000 claims description 5
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- 230000001105 regulatory effect Effects 0.000 abstract description 3
- 239000007788 liquid Substances 0.000 description 16
- 230000018109 developmental process Effects 0.000 description 6
- 238000003754 machining Methods 0.000 description 6
- 238000005498 polishing Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
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- 230000004323 axial length Effects 0.000 description 2
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/0018—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas with devices for making foam
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
- B05B1/34—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to influence the nature of flow of the liquid or other fluent material, e.g. to produce swirl
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/02—Spray pistols; Apparatus for discharge
- B05B7/10—Spray pistols; Apparatus for discharge producing a swirling discharge
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Abstract
The invention discloses a device and a method for actively controlling cavitation water jet to strengthen the inner surface of a micro hole, wherein the device consists of a nozzle main body and a cross cylinder, the cross cylinder consists of a cross cylinder body and four pistons, a through cross through hole is formed in the cross cylinder body, a control cavity is formed in the right middle of the cross through hole, a piston which is in sealing connection with the inner wall of the through hole and can move back and forth is arranged in each section of through hole of the cross through hole, an outlet of the nozzle main body is fixedly connected with an inlet of the control cavity, and the outlet of the control cavity is tightly adhered to the front end surface of a part to be processed with the micro hole; the volume of the control cavity and the distance from the axis of the water outlet are regulated by independently controlling the reciprocating motion of the pistons in different directions, so that different space sizes and shapes of the control cavity are formed, different pressure areas are formed on the surface areas in different positions and directions, which are required to be reinforced, in the micro hole, and the aim of reinforcing and processing the whole area of the inner surface of the micro hole is fulfilled.
Description
Technical Field
The invention relates to the field of strengthening treatment of the inner surface of a micro-hole, in particular to a processing technology for strengthening the inner surface of the micro-hole by adopting cavitation water jet.
Background
With the increasing demands of machine parts on precision and strength, especially in terms of micro holes and micro deep holes. Micropores refer to a pore diameter of less than 2nm, as defined by the International Union of Pure and Applied Chemistry (IUPAC). In the micromachining, it is considered that holes having a diameter of less than 0.1mm are micropores, and holes having a ratio of a depth of the holes to a diameter of more than 10 are deep holes. At present, in the advanced products and new products of various precision industries such as military industry, machinery, photoelectricity, instruments and meters, the application of micro holes and micro deep holes is becoming wider, for example: oil pump, oil nozzle, water jet, mold, etc. The requirements on the machining precision and the roughness of the micro holes are also higher and higher, the structural characteristics of the micro holes and the deep holes make the machining of the inner surfaces of the micro holes difficult, and the existing strengthening machining method cannot accurately control the strengthening machining of different parts of the inner surfaces of the micro holes.
The surface strengthening treatment is to artificially form a surface layer with different mechanical, physical and chemical properties from a matrix on the surface of a base material, so as to meet various strengthening function requirements of improving the corrosion resistance, the wear resistance, the heat resistance and the like of a workpiece. Work piece surfaces are typically strengthened by polishing, shot blasting, surface coating, anodic oxidation, and the like. The polishing depends on the grinding and rolling action of the fine polishing powder on the polishing wheel, at least the inner diameter of the polishing wheel needs to be accommodated, and the polishing wheel is not applicable to the inner surface of the micro hole; the sand blasting strengthening is to spray a large amount of high-speed moving shots onto the surface of a part, and the surface of the part is deformed by a certain attribute by utilizing the kinetic energy generated by the high-speed moving shots so as to achieve the purpose of strengthening. For strengthening the inner surface of the micro hole, the diameter of the shot to be used is too small, which is time-consuming and labor-consuming; the surface coating is to coat one or more layers of materials with better wear resistance, corrosion resistance and heat resistance on the surface of the workpiece so as to meet the requirement of strengthening the surface of the workpiece, however, the surface coating is difficult to control and coat to a large uniform degree for the micro-holes, and the precision of the micro-holes is very easy to influence.
The liquid generally contains microscopic bubbles that are invisible to the human eye. When the high-speed jet flows through the nozzle, the pressure at the outlet of the nozzle is suddenly reduced and is lower than the saturated vapor pressure of the fluid medium, so that a large amount of cavitation nuclei are generated, enter static water together with the high-speed jet and are strongly sheared with the static water, a local area in a flow field is instable, low-pressure vortex is generated, more cavitation nuclei are further inoculated by the low-pressure vortex, cavitation nuclei generated by the cavitation nuclei and the high-speed jet flow move downstream under the driving of the high-speed jet flow and are gathered to form cavitation bubble cloud, and when the ambient pressure is higher than the bubble internal pressure, the cavitation bubble cloud is intensively collapsed. The collapse process is very short and only between microseconds, but local high-temperature and high-pressure points can be generated, and meanwhile, shock waves and microjet with huge energy are generated, the speed of the microjet is more than 1500m/s, hot spots are formed in the environment, namely cavitation water jet, and the phenomenon that bubbles are generated and develop to collapse is called cavitation effect. And a great amount of heat energy and kinetic energy can be generated when the bubbles collapse, so that the bubble can be applied to the material strengthening processing. The fluidity and low density of the liquid make the liquid have the advantages of controllability, low cost, strong adaptability and the like when the inner surface of the hole is reinforced.
The cavitation jet nozzle structure disclosed in the Chinese patent publication No. CN110420792B and named as a cavitation jet nozzle structure capable of realizing the surface machining in the slot hole comprises a liquid inlet part, a resonant cavity part and a liquid outlet part. The main liquid inlet pipe and the auxiliary liquid inlet pipe of the liquid inlet part are combined to act together to generate high-speed jet flow and low-speed jet flow, the high-speed jet flow and the low-speed jet flow pass through the resonant cavity part, the resonant cavity part is matched with the ultrasonic amplitude transformer to generate micro-cavitation in the resonant cavity, the micro-cavitation is generated and grows up through the resonant cavity, then the micro-cavitation is driven by concentric jet flow to be ejected from the nozzle head, a large amount of cavitation generated by the concentric jet flow and conveyed by the resonant cavity impacts the inner wall surface of the slot hole at a small angle, and the micro-jet flow and the impact wave generated by the collapse of the high-speed impact wall surface of the cavitation are utilized to realize the processing of the inner surface of the slot hole and the irregular part. The whole nozzle structure can realize the strengthening processing of the inner surface of the narrow and small hole by using a cavitation mode. However, this nozzle structure has problems in that: the depth and each part of the processing of the inner surface of the micro hole cannot be actively controlled, and the final processing precision of the inner surface is affected. The strengthening device proposed in the document with the publication number of CN110106332A and the name of 'a swinging volume alternating micropore inner surface strengthening device' utilizes the alternation of a closed volume to change the pressure of liquid in the volume to generate cavitation effect, and causes an air cannon to collapse on the micropore inner wall to generate stress, thereby achieving the purpose of strengthening the micropore inner surface. However, the structure of the device is complex, and the whole of the inner surface of the micropore can only be systematically reinforced, so that the processing direction and the processing position of the inner surface can not be actively controlled. The cavitation shot blasting equipment and the method disclosed in the Chinese patent publication No. CN110129537 entitled "pressure alternating type micropore inner surface cavitation shot blasting equipment and working method" are characterized in that the internal pressure of a closed chamber is controlled by controlling the rotation of a motor to change the liquid volume of the closed chamber, so that the cavitation effect and the collapse of air bubbles are controlled, and the aim of strengthening the processing of the micropore inner surface is achieved, however, the device cannot actively control the pressure direction of water jet flow and the collapse position of the air bubbles.
Disclosure of Invention
The invention aims to solve the problems that the reinforcement processing of the inner surface of the existing micro-hole is limited by the aspect ratio of the micro-hole, the depth, the direction and the position of the energy generated by bubble collapse can not be actively controlled, the processing surface precision is low and the like, and provides a device for actively controlling cavitation jet flow to reinforce the inner surface of the micro-hole.
In order to achieve the above purpose, the technical scheme adopted by the device for actively controlling cavitation water jet to strengthen the inner surface of the micro hole is as follows: the cross cylinder consists of a cross cylinder body and four pistons, a through cross through hole is formed in the cross cylinder body, a control cavity is formed in a cavity in the middle of the cross through hole, each section of through hole of the cross through hole is internally provided with a piston which is connected with the inner wall of the through hole in a sealing way and can move back and forth, and the four pistons respectively and independently move; the four pistons are identical in structure, are respectively arranged in pairs, the central axes of the two opposite pistons are collinear, and the central axes of the two pairs of pistons are perpendicular to the central axis of the control cavity and intersect at the center of the control cavity; the outlet of the nozzle main body is fixedly connected with the inlet of the control cavity, and the outlet of the control cavity is tightly attached to the front end face of the part to be processed with the micro hole.
The nozzle body is sequentially provided with an inlet cavity, a resonant cavity and a water outlet from an inlet to an outlet, the water outlet is fixedly connected with the cross cylinder body, and the inner diameters of the inlet cavity, the resonant cavity and the water outlet are sequentially reduced.
The technical scheme of the method for actively controlling cavitation water jet by adopting the device for strengthening the inner surface of the micro hole is as follows:
the four pistons move until the end surfaces of the four pistons are flush with the inner wall of the outlet of the nozzle main body;
high-pressure water flows through the nozzle body to generate a bubble water jet flow, and flows into the control cavity;
the different distances between the four pistons and the center of the control cavity are controlled, so that the control cavity forms different working volumes and shapes, and the front and rear half section center areas and the different radial areas of the surface in the micro hole are respectively reinforced and processed.
Further, when the front half section of the micro hole is reinforced, the distance between the pair of pistons is enlarged, the working volume of the control cavity is increased, the travel of cavitation water jet is shortened, cavitation collapses in the front half section of the micro hole, and the central area of the front half section of the micro hole is reinforced.
Further, when the latter half of the micro hole is reinforced, the distance between the pair of pistons is reduced, so that the working volume of the control cavity is reduced, the travel of cavitation water jet is prolonged, cavitation is collapsed again in the latter half of the micro hole, and the central area of the latter half of the micro hole is reinforced.
Further, the other pair of pistons are controlled to work simultaneously, one piston of the other pair of pistons is far away from the center of the control cavity, the other piston is close to the center of the control cavity, the direction of the cavitation water jet is changed, the cavitation water jet obliquely enters the micro hole, and the first half semicircular cambered surface area is impacted.
Further, the other pair of pistons are controlled to work simultaneously, one piston of the other pair of pistons is far away from the center of the control cavity, the other piston is close to the center of the control cavity, the direction of the cavitation water jet is changed, the cavitation water jet obliquely enters the micro hole, and the second half semicircular cambered surface area is impacted.
Compared with the prior art, the invention has the following outstanding beneficial effects:
(1) According to the invention, the water outlet of the nozzle is connected with the cross-shaped cylinder to control cavitation water jet, the piston in different directions is independently controlled to reciprocate, the volume of the control cavity and the distance away from the axis of the water outlet are regulated, different space sizes and shapes of the control cavity are formed to control the variable cross section of the water jet outlet carrying cavitation water jet, so that vortex and negative pressure are generated, the pressure and the flow direction of the water jet carrying cavitation water are influenced, the size and the direction of the water pressure of the water outlet are controlled, different pressure areas are formed in surface areas of different positions and directions needing strengthening in the micro-hole, the pressure size of the water jet and the pressure values of different areas in the micro-hole are controllably regulated, and the stroke and the direction of cavitation in the water jet in the stage of initiation, development, falling and collapse are actively controlled. When the pressure of the inner surface of the micro hole reaches the collapse pressure of the cavitation, the cavitation collapses, and the high-temperature high-pressure deformation of the inner surface of the micro hole is released. The depth and the direction of collapse of cavitation bubbles on the inner surface of the micro hole are controlled by controlling the travel length of the water pressure of the water outlet to be reduced to collapse pressure of cavitation bubbles, the water flow direction of cavitation bubbles carried by the water outlet is controlled, different radial areas of the inner surface of the micro hole are reinforced, and the aim of reinforcing and processing the whole area of the inner surface of the micro hole is fulfilled.
(2) According to the invention, the liquid volume and the shape of the closed chamber are actively controlled by controlling the closing degree of the piston in different directions, and finally, the collapse positions of cavitation bubbles at different radial positions and different axial positions on the inner surface of the micro hole are controlled, so that the problem that cavitation water jet can only singly strengthen a certain area of the inner surface of the micro hole is solved, the strengthening treatment of each depth of the inner surface of the micro hole in the radial and axial directions is realized, and the strengthening uniformity, the continuity and the strengthening efficiency of the inner surface of the micro hole are improved.
(3) The invention uses cavitation impact generated when cavitation effect hollow bubbles collapse to flexibly hammer the inner surface of the micro-hole, achieves the effect of strengthening the inner surface of the micro-hole, can realize different strength of strengthening the inner surface of the micro-hole by changing the size of the nozzle and adjusting the cooperation between the water flow pressure and the cross-shaped cylinder, strengthens the inner surfaces of the micro-holes with different apertures, the inner surfaces of the micro-holes with different lengths, the micro-holes with different shapes and the micro-holes with different materials, improves the strengthening uniformity, the continuity and the strengthening efficiency of the inner surface of the micro-hole, and has the advantages of simple structure, low processing cost, low operation difficulty, high processing efficiency and the like.
Drawings
The invention is described in further detail below with reference to the attached drawings and detailed description:
FIG. 1 is a schematic diagram of a three-dimensional structure of an apparatus for actively controlling cavitation water jet to strengthen the inner surface of a micro-hole;
FIG. 2 is a schematic cross-sectional view of the device for actively controlling cavitation water jet to strengthen the inner surface of a micro-hole.
FIG. 3 is a schematic diagram of the operation of the apparatus of FIG. 2 to strengthen the front half area of the interior surface of a micro-hole;
FIG. 4 is a schematic diagram of the operation of the first half of the semi-arc surface for strengthening the inner surface of the micro-hole based on FIG. 3;
FIG. 5 is a schematic diagram of the operation of the apparatus of FIG. 2 to strengthen the second half of the interior surface of the micro-hole;
fig. 6 is a schematic diagram of the operation of the second half of the semi-arc surface of the inner surface of the reinforced micro-hole based on fig. 5.
Reference numerals illustrate: 1. a nozzle body; 2. a cross-shaped cylinder; 3. a first piston; 4. a second piston; 5. a third piston; 6. a piston IV; 7. a part to be processed; 8. an inlet chamber; 9. an inlet constriction face; 10. a resonant cavity; 11. an outlet constriction surface; 12. a thread; 13. a water outlet; 14. a control chamber; 15. a micro hole; 16. cavitation; 17. a first half-section of semicircular cambered surface; 18. a second half-section of semicircular cambered surface; 19. a first semicircular cambered surface at the rear half section; 20. and the second half section is a semicircular cambered surface.
Detailed Description
The device for actively controlling cavitation jet flow to strengthen the inner surface of a micro hole comprises a nozzle main body 1 and a cross-shaped air cylinder 2, wherein the outlet of the nozzle main body 1 is fixedly connected with the inlet of the cross-shaped air cylinder 2, and the outlet of the cross-shaped air cylinder 2 is opposite to a part 7 to be processed with the micro hole 15. The center axis of the nozzle body 1 is collinear with the center axis of the cross cylinder 2 in the inlet-outlet direction and the center axis of the minute hole 15, and is the X-axis direction in fig. 1.
The cross cylinder 2 is composed of a cross cylinder body and four pistons, a through cross through hole is formed in the cross cylinder body, and a control cavity 14 is formed in the middle of the cross through hole, so that the inlet and the outlet of the cross cylinder 2 are also the inlet and the outlet of the control cavity 14, and the center of the control cavity 14 is the origin O in FIG. 1 and is also the center of the cross cylinder 2. The central axis of the through hole of the cross-shaped through hole is perpendicular to the central axis of the cross-shaped cylinder 2 in the direction from the inlet to the outlet, and the directions of the central axes of the two through holes are the Y-axis direction and the Z-axis direction in FIG. 1 respectively.
There is a piston in each section of the cross-shaped through hole, so there are four pistons, namely piston one 3, piston two 4, piston three 5 and piston four 6. The four pistons enclose the control chamber 14 as a closed volume, each piston being sealed from the corresponding through-hole wall and being movable back and forth along the through-hole wall, closer to or further from the centre of the control chamber 14, resulting in a reduced or increased working volume of the control chamber 14. The piston can extend into the control chamber 14 when it is close to the centre of the control chamber 14, decreasing the working volume of the control chamber 14, and increasing the working volume of the control chamber 14 when it is far from the centre of the control chamber 14.
The four pistons are identical in structure, are arranged two by two respectively, the central axes of the two opposite pistons are collinear, and the central axes of the two pairs of pistons are perpendicularly intersected at the center of the control cavity 14. Namely: piston one 3 is opposite to piston three 5 and the central axis is collinear (Y direction), and piston two 4 is opposite to piston three 5 and the central axis is collinear (Z direction). The central axes of the first piston 3 and the third piston 5 and the central axes of the second piston 4 and the third piston 5 are perpendicular to the central axis of the control chamber 14 and perpendicularly intersect at the center O of the control chamber 14.
The four pistons are independently controlled by an external controller (the controller is omitted in the figure), and the controller independently controls the four pistons to move respectively.
The outlet end of the nozzle body 1 is fixedly connected with a cross cylinder body through a thread 12 and is connected with the inlet of the control cavity 14, the inlet of the nozzle body 1 and the inlet of the control cavity 14 are sealed by a sealing ring, and the tightness of the inner cavity of the nozzle body 1 and the control cavity 14 is kept. During the strengthening processing, the outlet of the control cavity 14 is closely attached to the front end surface of the part 7 to be processed, so that the control cavity 14 and the micro holes 15 are sealed, and the nozzle main body 1, the control cavity 14 and the micro holes 15 are communicated and sealed.
The nozzle main body 1 is provided with an inlet cavity 8, a resonant cavity 10 and a water outlet 13 from the inlet to the outlet, and the water outlet 13 is connected with the cross cylinder body through threads 12. The inner diameters of the inlet chamber 8, the resonant cavity 10 and the water outlet 13 are sequentially reduced, so that the transition surface between the inlet chamber 8 and the resonant cavity 10 forms an inlet contraction surface 9, and the transition surface between the resonant cavity 10 and the water outlet section 13 forms an outlet contraction surface 11. The axial length of the resonant cavity 10 is greater than the axial length of the inlet cavity 8 and the water outlet 13.
In the invention, the radial sectional area of the water outlet 13 is the same as the radial sectional area of the control cavity 14 and is smaller than the radial sectional area of the micro hole 15.
As shown in fig. 3, 4, 5 and 6, the water pressure of the input nozzle main body 1 is at least 25MPa, high-pressure water flows into the resonant cavity 10 through the inlet cavity 8, and due to the existence of the inlet contraction surface 9, the liquid inside the two cavities of the inlet cavity 8 and the resonant cavity 10 has a velocity gradient, cavitation occurs and starts at the inner wall of the inlet contraction surface 9, and cavitation bubbles 16 grow and grow along with the flowing of the liquid. Thus, the nozzle body 1 can accumulate the pressure of the high-pressure liquid flow and convert it into fluid kinetic energy, and the pressure difference of the section determines the velocity of the water jet, so that the cavitation liquid in the resonant cavity 10 can entrain a large amount of cavitation bubbles 16 and flow into the control cavity 14. The volume of the control cavity 14 is changed to control the liquid pressure in the control cavity 14 through the movement of the four pistons, and the strokes and directions of cavitation bubbles in the water jet flow in the stages of initiation, development, falling and collapse are actively controlled. When the pressure in the micro holes 15 of the part 7 to be processed reaches the collapse pressure of the cavitation bubbles 16, the cavitation bubbles 16 collapse, when the pressure is smaller than the collapse pressure of the cavitation bubbles 16, the cavitation bubbles 16 continue to advance in the micro holes 15 along with water flow, when the pressure reaches the collapse pressure, the cavitation bubbles 16 collapse, and the purpose of strengthening different depths of the inner surfaces of the micro holes 15 is achieved by controlling the collapse pressure of the cavitation bubbles 16 in water jet. The size of the outlet section of the water outlet 13 can be restrained by independently controlling the position of the piston extending into the control cavity 14, the outflow direction of the water jet carrying the cavitation bubbles 16 is changed, the cavitation bubbles 16 generated by cavitation continuously develop along with the movement of the water jet, the pressure of the inner surface of the micro holes 15 is reduced to the collapse pressure of the cavitation bubbles 16, the collapse pressure of the cavitation bubbles 16 reaches different parts of the inner surface of the micro holes 15, very high pressure pulses and micro jet flows are generated, and the inner surface of the micro holes 15 is continuously subjected to reinforced impact.
Along the length direction of the central axis of the micro-hole 15, the micro-hole 15 may be divided into a front half section and a rear half section, wherein the front half section is close to the control chamber 14, and the rear half section is far from the control chamber 14. The inner surfaces of the front half section and the rear half section of the micro-hole 15 can be regarded as surfaces formed by seamless connection of two identical semi-arc surfaces along the circumferential direction, the front half section is formed by seamless connection of a first semi-arc surface 17 of the front half section and a second semi-arc surface 18 of the front half section, and the rear half section is formed by seamless connection of a first semi-arc surface 19 of the rear half section and a second semi-arc surface 20 of the rear half section. The two semi-arc surfaces of the front half section and the rear half section should be opposite to the two pistons opposite to each other in the axial direction.
In the initial position of the invention, the four pistons are all moved to the same distance between the end surfaces of the four pistons and the center of the control cavity 14, the end surfaces of the four pistons are flush with the outlet of the nozzle main body 1, namely the inner wall of the water outlet 13, the distance between the two opposite pistons is equal to the inner diameter of the water outlet 13, as shown in fig. 2, at the moment, the pistons do not extend into the control cavity 14, and the working volume of the control cavity 14 is the original size.
When the micro hole 15 is machined in an intensified manner, four pistons work and are responsible for four areas of the semi-circular arc surfaces of the front half section and the rear half section of the micro hole 15, the diameter and the pressure of the closed chamber in the control cavity 14 are changed through the reciprocating motion of the pistons, the burst area of the air bubble 16 is controlled, and the intensified machining of different areas and directions of the inner surface of the micro hole 15 is actively controlled. By controlling different distances between the two pairs of pistons and the center of the control cavity 14, the control cavity 14 forms different effective working volumes and shapes, the water flow direction of cavitation carried by the outlet of the control cavity 14 is changed, the pressure of water flow is rapidly reduced to cavitation collapse pressure, so that cavitation collapses in different directions on the front half section and the rear half section of the inner surface of the micro hole 15, and different radial areas on the front half section and the rear half section of the inner surface of the micro hole 15 are reinforced. When the inner surface of the front half section of the micro hole 15 needs to be reinforced, the distance between the two coaxially opposite pistons is enlarged, so that the working volume of the control cavity 14 is enlarged, the pressure in the control cavity 14 is smaller than the pressure at the water outlet 13, the strokes of cavitation bubble primary, development, falling and collapse stages are shortened, the pressure of water flow is quickly reduced to the collapse pressure of the cavitation bubble 16, the cavitation bubble 16 collapses in the front half section of the inner surface of the micro hole 15, and the reinforcement of the inner surface of the front half section of the micro hole 15 is realized. When the inner surface of the second half of the micro hole 15 needs to be reinforced, the distance between a pair of pistons is reduced, so that the volume of the control cavity 14 is reduced, the pressure in the control cavity 14 is larger than the pressure at the water outlet 13, the strokes of cavitation bubble primary, development, falling and collapse stages are prolonged, the pressure of water flow is slowly reduced to the cavitation bubble collapse pressure, and the water jet flow carrying the cavitation bubbles 16 is prolonged, so that the cavitation bubbles 16 collapse again in the second half of the micro hole 15. The water flow direction carrying the cavitation bubbles 16 from the water outlet 13 is changed by controlling the different distances between the other pair of two opposite pistons and the center of the control cavity 14, so that the cavitation bubbles 16 collapse in different directions on the inner surfaces of the front half section and the rear half section of the micro holes 15, and different radial areas of the front half section and the rear half section of the inner surfaces of the micro holes 15 are reinforced, namely the semicircular cambered surfaces of the front half section and the rear half section of the micro holes 15 are reinforced. The method comprises the following steps:
as shown in fig. 3, the high-pressure water jet flows through the nozzle body 1, from the inlet chamber 8, the resonant chamber 10, the water outlet section 13 into the control chamber 14 of the cavitation jet control device. The piston two 4 and the piston four 6 move the same distance away from the center of the control cavity 14 at the same time, the working volume of the control cavity 14 is increased, the pressure in the control cavity 14 is naturally smaller than the pressure at the water outlet 13, the strokes of cavitation bubbles 16 in water jet flow in the primary, development, falling and collapse stages are shortened, and the water flow can only enter the first half section of the micro hole 15. When the water flow enters the front half section of the micro-hole 15, the pressure is reduced to the collapse pressure of the cavitation bubbles 16 in a short distance, that is, the collapse stroke of the cavitation bubbles 16 from the collapse is shortened, and therefore, the collapse of the cavitation bubbles 16 strengthens the middle area of the front half section of the inner surface of the micro-hole 15.
As shown in fig. 4, when the first half arc surface 17 of the inner surface of the minute hole 15 needs to be reinforced, the first half arc surface 17 is positioned to face the third piston 5 in the axial direction. In the state that the positions of the piston two 4 and the piston four 6 shown in fig. 3 are unchanged, the control piston one 3 and the control piston three 5 work simultaneously, the piston one 3 is far away from the center of the control cavity 14, the piston three 5 is close to the control cavity 14 and stretches into the control cavity 14, and basically the piston three 5 extrudes water jet in the direction of the piston one 3, so that the direction of the water jet is changed. At this time, the direction of cavitation bubbles 16 in the water jet is changed in the stage of initiation, development, falling and collapse, so that the high-pressure water flow carrying the cavitation bubbles 16 flows along the arrow direction of fig. 4, the high-pressure water flow avoids the piston three 5, and after passing through the working chamber of the control chamber 14, the hydraulic pressure in the first half arc surface area 17 reaches the collapse pressure of the cavitation bubble 16, so that the first half arc surface area 17 is strengthened.
Similarly, when the first half arc surface second 18 of the inner surface of the micro hole 15 is reinforced, the first half arc surface second 18 and the first half arc surface first 17 form the entire first half of the micro hole 15, and the first half arc surface second 18 faces the first cylinder 2 and the first piston 3 in the axial direction. In the state that the positions of the piston two 4 and the piston four 6 are kept unchanged, the piston one 3 and the piston three 5 return to the initial positions firstly, then the piston one 3 is close to the center of the control cavity 14 and stretches into the control cavity 14, the piston three 5 is far away from the center of the control cavity 14, the piston one 3 stretches inwards into the control cavity 14 to squeeze water jet to change the direction of the water jet, so that high-pressure water flow carrying cavitation bubbles 16 avoids the piston one 3, and after passing through the working containing cavity of the control cavity 14, the water jet obliquely enters the micro hole 15 towards the piston three 5, namely impacts against the semicircular cambered surface two 18 of the first half section to strengthen.
As shown in fig. 5, the high-pressure water jet flows through the inlet chamber 8, the resonant chamber 10, the water outlet section 13 and into the control chamber 14. The piston two 4 and the piston four 6 move from the initial position simultaneously by the same distance towards the centre of the control chamber 14, reducing the working volume of the control chamber 14. At this time, the water pressure in the control chamber 14 is greater than the collapse pressure of the cavitation bubbles 16, and the water jet enters the second half of the micro holes 15, strengthening the middle area of the second half of the micro holes 15.
As shown in fig. 6, when the second half-arc surface 20 of the minute hole 15 needs to be reinforced, the first half-arc surface 20 is positioned to face the first piston 3 in the axial direction. In the state of fig. 5, the second piston 4 and the fourth piston 6 still keep still, the third piston 5 moves towards the direction away from the center of the control cavity 14, the first piston 3 stretches inwards into the control cavity 14 to squeeze the water jet to change the direction of the water jet, the water flow continues to be pressurized after passing through the water outlet 13, and the pressure is larger than the collapse pressure of cavitation bubbles, so that the stroke from cavitation bubbles inoculation to collapse is prolonged. The high-pressure water flow carrying the cavitation bubbles 16 avoids the first piston 3, flows along the arrow direction of fig. 6 after passing through the control cavity 14 with the changed shape and volume, enters the micro holes 15 obliquely towards the third piston 5, reduces the pressure, and collapses at the second half-section half-arc surface 20 when the cavitation collapse pressure is reached, and strengthens the second half-section half-arc surface 20.
Similarly, when the first half-arc surface 19 of the micro hole 15 needs to be reinforced, the first half-arc surface 19 of the second half-arc surface is positioned to face the third piston 5 in the axial direction. The second piston 4 and the fourth piston 6 still remain motionless, and contrary to the method shown in fig. 5, the first piston 3 moves away from the center of the control chamber 14, the third piston 5 stretches into the control chamber 14 to squeeze the water jet to change the direction, the high-pressure water flow obliquely enters the micro hole 15 towards the first piston 3, and the second half semicircular arc surface 19 is reinforced.
Claims (10)
1. An active control cavitation water jet reinforced micro-hole inner surface device is characterized in that: the device consists of a nozzle main body (1) and a cross-shaped air cylinder (2), wherein the cross-shaped air cylinder (2) consists of a cross-shaped cylinder body and four pistons, a through cross-shaped through hole is formed in the cross-shaped cylinder body, a control cavity (14) is formed in a cavity in the middle of the cross-shaped through hole, a piston which is in sealing connection with the inner wall of the through hole and can move back and forth is arranged in each section of through hole of the cross-shaped through hole, and the four pistons respectively and independently move; the four pistons have the same structure, are respectively arranged in pairs, the central axes of the two opposite pistons are collinear, and the central axes of the two pairs of pistons are perpendicular to the central axis of the control cavity (14) and intersect at the center of the control cavity (14); the outlet of the nozzle main body (1) is fixedly connected with the inlet of the control cavity (14), and the outlet of the control cavity (14) is tightly attached to the front end surface of the part (7) to be processed with the micro hole (15).
2. The device for actively controlling cavitation water jet to strengthen the inner surface of a micro-hole according to claim 1, which is characterized in that: the nozzle main body (1) comprises an inlet cavity (8), a resonant cavity (10) and a water outlet (13) from an inlet to an outlet, the water outlet (13) is fixedly connected to the cross cylinder body, and the inner diameters of the inlet cavity (8), the resonant cavity (10) and the water outlet (13) are sequentially reduced.
3. The device for actively controlling cavitation water jet to strengthen the inner surface of a micro-hole according to claim 2, which is characterized in that: the radial sectional area of the water outlet (13) is the same as the radial sectional area of the control cavity (14) and is smaller than the radial sectional area of the micro hole (15).
4. The device for actively controlling cavitation water jet to strengthen the inner surface of a micro-hole according to claim 1, which is characterized in that: the central axes of the nozzle body (1), the control chamber (14) and the micro-holes (15) are collinear.
5. A method of strengthening the interior surface of a micro-hole using the apparatus of claim 2, comprising:
the four pistons move to the end surfaces of the four pistons to be flush with the inner wall of the outlet of the nozzle main body (1);
the high-pressure water flows through the nozzle main body (1) to generate a bubble water jet flow, and flows into the control cavity (14);
the different distances between the four pistons and the center of the control cavity (14) are controlled, so that the control cavity (14) forms different working volumes and shapes, and the central areas of the front and rear half sections and the different radial areas of the inner surface of the micro hole (15) are respectively reinforced.
6. The method for reinforcing an inner surface of a micro-hole according to claim 5, wherein: when the front half section of the micro hole (15) is reinforced, the distance between a pair of pistons in the four pistons is enlarged, so that the working volume of the control cavity (14) is increased, the travel of cavitation water jet is shortened, cavitation is collapsed in the front half section of the micro hole (15), and the central area of the front half section of the micro hole (15) is reinforced.
7. The method for reinforcing an inner surface of a micro-hole according to claim 5, wherein: when the second half section of the micro hole (15) is reinforced, the distance between a pair of pistons in the four pistons is reduced, so that the working volume of the control cavity (14) is reduced, the travel of cavitation water jet is prolonged, cavitation is collapsed again in the second half section of the micro hole (15), and the central area of the second half section of the micro hole (15) is reinforced.
8. The method for reinforcing an inner surface of a micro-hole according to claim 6, wherein: when the first half of the semicircular cambered surface on the inner surface of the micro hole (15) needs to be reinforced, the position of the first half of the semicircular cambered surface faces to a piston III (5) in the four pistons in the axial direction, a piston II (4) and a piston IV (6) which are opposite in position in the four pistons are kept motionless, the piston I (3) and a piston III (5) which is opposite to the piston I (3) are controlled to work simultaneously, the piston I (3) is far away from the center of the control cavity (14), the piston III (5) is close to the center of the control cavity (14), the direction of the cavitation water jet is changed, so that the cavitation water jet obliquely enters the micro hole (15) to impact the first half of the semicircular cambered surface area.
9. The method for strengthening the inner surface of a micro-hole according to claim 7, wherein: when the second half of the semicircular cambered surface on the inner surface of the micro hole (15) needs to be reinforced, the second half of the semicircular cambered surface is axially opposite to the first piston (3) of the four pistons, the second piston (4) and the fourth piston (6) which are opposite to each other in the four pistons are kept motionless, the third piston (5) which is opposite to the first piston (3) moves in the central direction away from the control cavity (14), the first piston (3) stretches into the control cavity (14) to extrude the water jet to change the direction of the water jet, so that the cavitation water jet obliquely enters the micro hole (15) to impact the second half of the semicircular cambered surface area.
10. The method for strengthening the inner surface of a micro-hole according to claim 7, wherein: the water pressure of the high-pressure water flow input into the nozzle body (1) is at least 25MPa.
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| CN202210972594.7A CN115138494B (en) | 2022-08-15 | 2022-08-15 | Device and method for actively controlling cavitation water jet to strengthen inner surface of micro hole |
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| GB1081699A (en) * | 1964-12-17 | 1967-08-31 | Maurice Jerry Finn | Spray-producing nozzles and apparatus embodying such nozzles |
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| CN204338357U (en) * | 2014-10-23 | 2015-05-20 | 西华大学 | A kind of centralized rotation Cavitation jet nozzle |
| JP2017203392A (en) * | 2016-05-10 | 2017-11-16 | 株式会社スギノマシン | Reciprocating pump |
| CN110055390A (en) * | 2019-04-28 | 2019-07-26 | 江苏大学 | A kind of pressure alternation immersion bore area intensifying device and method |
| CN216936545U (en) * | 2022-03-10 | 2022-07-12 | 天津捷强动力装备股份有限公司 | Non-submerged cavitation jet nozzle |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1081699A (en) * | 1964-12-17 | 1967-08-31 | Maurice Jerry Finn | Spray-producing nozzles and apparatus embodying such nozzles |
| CN102513237A (en) * | 2011-12-28 | 2012-06-27 | 天津海源流体工程技术有限公司 | Cavitation type ultrahigh pressure water hammer type water gun sprayer |
| CN204338357U (en) * | 2014-10-23 | 2015-05-20 | 西华大学 | A kind of centralized rotation Cavitation jet nozzle |
| JP2017203392A (en) * | 2016-05-10 | 2017-11-16 | 株式会社スギノマシン | Reciprocating pump |
| CN110055390A (en) * | 2019-04-28 | 2019-07-26 | 江苏大学 | A kind of pressure alternation immersion bore area intensifying device and method |
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