CN112974004A

CN112974004A - Jet nozzle for strengthening surface of limited part of aviation component

Info

Publication number: CN112974004A
Application number: CN202110181631.8A
Authority: CN
Inventors: 张显程; 张平; 韩晓宁; 涂善东; 李志强
Original assignee: East China University of Science and Technology; AVIC Beijing Aeronautical Manufacturing Technology Research Institute
Current assignee: East China University of Science and Technology; AVIC Beijing Aeronautical Manufacturing Technology Research Institute
Priority date: 2021-02-09
Filing date: 2021-02-09
Publication date: 2021-06-18
Anticipated expiration: 2041-02-09
Also published as: CN112974004B; WO2022170696A1

Abstract

The invention relates to a jet nozzle for strengthening the surface of a limited part of an aviation component, which comprises: the incidence structure is provided with an incidence port, an incidence cavity and a primary throat pipe which are sequentially communicated along the axial direction; the exit structure is provided with a secondary throat pipe and an exit port which are sequentially communicated along the axial direction; and the sleeve is positioned between the incident structure and the emergent structure and is provided with a self-oscillation cavity which is respectively communicated with the primary throat pipe and the secondary throat pipe. The jet nozzle for strengthening the surface of the limited part of the aviation component can effectively improve the cavitation effect of water jet by arranging the incident cavity, the primary throat pipe, the self-excited oscillation cavity and the bipolar oscillation and bipolar contraction cavity of the secondary throat pipe, thereby improving the residual compressive stress of the surface layer and prolonging the fatigue life.

Description

Jet nozzle for strengthening surface of limited part of aviation component

Technical Field

The invention relates to the field of cavitation jet flow strengthening, in particular to a jet flow nozzle for strengthening the surface of a limited part of an aviation component.

Background

Inside the liquid, the process of cavitation formation, development and collapse is called cavitation. The liquid generally contains tiny bubbles which can not be seen by human eyes, when the liquid flows through a low-pressure area, the tiny bubbles expand rapidly, then tiny vacuoles are formed at the tiny bubbles, and the liquid cavitated in the low-pressure area flows to a high-pressure area along with a large amount of bubbles to form two-phase flow movement. The cavitation bubble moves along with the mainstream in the liquid, and the cavitation bubble volume will reduce when the surrounding liquid pressure increases, and then lead to the cavitation bubble to take place to burst, and the process of bursting out is very short, only between the microsecond, but can produce local high temperature high pressure point, simultaneously along with producing huge shock wave of energy and microjet, the speed of microjet is greater than 1500m/s, can form "hot spot" under this kind of environment, and then causes the cavitation erosion to the material surface. With the further understanding of cavitation phenomena and the development of cavitation theory, people find that cavitation is not completely harmful, and the method has high application value in the fields of chemical engineering, medical engineering, marine military and the like.

The cavitation water jet has the advantages of high efficiency, environmental protection, easy operation and the like, so that the cavitation water jet is widely applied to various occasions, such as industries of material cutting and crushing, petroleum mine exploitation, degradation of organic pollutants in water and the like, and has high economic value, and the performance of submerging the water jet cavitation strengthening material is one of successful applications of cavitation phenomena. To date, cavitation water jets are increasingly being used to alter the surface properties of materials. The surface performance of the material is strengthened by utilizing the high-speed water jet, and the key point is that the surface of the material is subjected to plastic deformation below the recrystallization temperature, so that residual stress is introduced into the surface layer of the material, and an ideal tissue structure is obtained. Because the surface residual stress can increase the surface hardness, the initiation of a fatigue crack source and the propagation of cracks can be effectively controlled, and the purpose of prolonging the fatigue life of the material is achieved.

Jet cavitation is generally achieved by a jet nozzle, and liquid such as high-pressure water enters the nozzle to generate cavitation, and then is ejected out of the nozzle, so that the surface of a material is strengthened. Most of the existing jet nozzles are of fan-shaped and angular structures, and the cavitation effect is poor.

Disclosure of Invention

The invention aims to provide a jet nozzle for strengthening the surface of a limited part of an aviation component, so as to improve the jet cavitation rate and further improve the jet strengthening effect.

The invention provides a jet nozzle for strengthening the surface of a limited part of an aviation component, which comprises:

the incidence structure is provided with an incidence port, an incidence cavity and a primary throat pipe which are sequentially communicated along the axial direction;

the exit structure is provided with a secondary throat pipe and an exit port which are sequentially communicated along the axial direction;

and the sleeve is positioned between the incident structure and the emergent structure and is provided with a self-oscillation cavity which is respectively communicated with the primary throat pipe and the secondary throat pipe.

Further, the incident cavity is in a horn shape with a tapered diameter.

Further, the primary throat and the secondary throat are both slender cylinders.

Further, the axial length ratio of the primary throat to the secondary throat is 8: 1.

Furthermore, the incident structure sequentially comprises an inlet section, an incident section and a throat section along the axial direction, the incident port is located in the inlet section, the incident cavity is located in the incident section, and the primary throat is located in the throat section.

Further, the sleeve is sleeved on the outer side of the throat pipe section and clings to the incidence section.

Further, a gasket is arranged between the sleeve and the incident section.

Further, the incident section, the sleeve and the exit structure are fastened and connected by bolts.

Further, the exit structure has a conical protrusion on an end thereof adjacent to the sleeve.

Further, the exit port is hemispherical.

The jet nozzle for strengthening the surface of the limited part of the aviation component can effectively improve the cavitation effect of water jet by arranging the incident cavity, the primary throat pipe, the self-excited oscillation cavity and the bipolar oscillation and bipolar contraction cavity of the secondary throat pipe, thereby improving the residual compressive stress of the surface layer and prolonging the fatigue life.

Drawings

FIG. 1 is a side view of a jet nozzle for surface strengthening of restricted areas of aerospace components provided by embodiments of the invention;

FIG. 2 is a cross-sectional view C-C of FIG. 1;

FIG. 3 is a schematic diagram of an incident structure of a jet nozzle for surface strengthening of a restricted portion of an aerospace component according to an embodiment of the invention;

FIG. 4 is a half sectional view of FIG. 3;

fig. 5A and 5B show the residual stress distribution of different experimental protocols of the present invention and the control group, respectively.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1 and fig. 2, an embodiment of the present invention provides a jet nozzle for reinforcing the surface of a restricted portion of an aircraft component, comprising an incident structure 1, a sleeve 2 and an exit structure 3 which are sequentially connected in an axial direction, wherein the incident structure 1 has an incident port 111, an incident cavity 121 and a primary throat 131 which are sequentially connected in the axial direction, the sleeve 2 has a self-oscillating cavity 21 which has a V-shaped wall surface and generates vortex vibration when a jet flows to the V-shaped wall surface, thereby realizing self-oscillation, the exit structure 3 has a secondary throat 31 and an exit port 32 which are sequentially connected in the axial direction, the self-oscillating cavity 21 is respectively communicated with the primary throat 131 and the secondary throat 31, so that the incident port 111, the incident cavity 121, the primary throat 131, the self-oscillating cavity 21, the secondary throat 31 and the exit port 32 form a system which is sequentially connected in the axial direction, and high-pressure water enters the jet nozzle from the incident port 111, the jet flow passes through the incident cavity 121, the primary throat pipe 131, the self-oscillation cavity 21, the secondary throat pipe 31 and the exit port 32 in sequence, and is ejected out from the exit port 32 to the surface of a workpiece to be machined after cavitation is realized, so that jet flow strengthening of the workpiece to be machined is realized, the surface residual stress of the workpiece is improved, and the fatigue life of the workpiece is prolonged.

The incident cavity 121 is a resonant cavity, which may be a horn-shaped cavity with a tapered diameter, and the diameter of the entrance of the cavity is smaller than that of the entrance port 111, and the high-pressure water in the entrance port 111 passes through the incident cavity 121 with a smaller diameter and exits from the entrance cavity 121 from the end with the smaller diameter, so that resonance may be generated, thereby increasing the cavitation rate.

The primary throat pipe 131 and the secondary throat pipe 31 are both in a slender cylinder shape, the diameters of the incidence cavity 121 and the self-excited oscillation cavity 21 are far larger than the diameters of the primary throat pipe 131 and the secondary throat pipe 31, so that two contraction structures from the incidence cavity 121 to the primary throat pipe 131 and from the self-excited oscillation cavity 21 to the secondary throat pipe 31 can be formed, the contraction of the secondary throat pipe can accelerate the air solubility of jet media, and the cavitation efficiency of the water jet is higher.

Preferably, the length ratio of the primary throat 131 to the secondary throat 31 in the axial direction is 8:1, so that the oscillation action of the incident cavity 121 and the self-oscillation cavity can be improved, thereby improving the cavitation rate.

The exit port 32 may be a hemispherical structure, which may reduce the area of the jet-enhanced region of influence, thereby increasing the enhancement effect.

As shown in fig. 3 and 4, the incident structure 1 includes an entrance section 11, an incident section 12, and a throat section 13 in sequence along the axial direction, wherein the incident section 12 is a disc-shaped structure, and the diameter thereof is much larger than the diameters of the entrance section 11 and the throat section 13. The entrance port 111, the entrance cavity 121 and the primary throat 131 are opened on the entrance section 11, the entrance section 12 and the throat section 13, respectively.

The sleeve 2 is sleeved on the outer side of the throat pipe section 13, one end of the sleeve 2 is tightly attached to the incident section 12, the emergent structure 3 is tightly attached to the other end of the sleeve 2, and the incident section 12, the sleeve 2 and the emergent structure 3 are fastened and connected together through the bolt 4, so that an integral structure of the jet nozzle for strengthening the surface of the limited part of the aviation component is formed.

A gasket 5 may be provided between the entrance section 12 and the sleeve 2 to provide a seal, and similarly, between the sleeve 2 and the exit structure 3.

The end of the exit structure 3 close to the sleeve 2 is provided with a conical protrusion 33, the space between the conical protrusion 33 and the throat section 13 is the self-oscillation cavity 21, and the conical protrusion 33 can change the flowing state of the jet medium in the self-oscillation cavity 21, so that the self-oscillation effect is improved.

According to the jet nozzle for strengthening the surface of the limited part of the aviation component, provided by the embodiment of the invention, the incident cavity 121, the primary throat 131, the self-excited oscillation cavity 21 and the bipolar oscillation and bipolar contraction cavity of the secondary throat 31 are arranged, so that the water jet cavitation effect can be effectively improved, the residual compressive stress on the surface layer is further improved, and the fatigue life is prolonged.

In this embodiment, 2219 aluminum alloy is taken as a research object, a water jet strengthening experimental scheme based on different jet parameters is formulated by using the jet nozzle for strengthening the surface of the limited part of the aviation component, as shown in table 1, the jet angles are 0 °, 10 ° and 20 °, and then the experiments with the jet pressure of 25MPa, 50MPa and 75MPa are performed at each jet angle. In order to prove the beneficial effect of the jet nozzle for strengthening the surface of the limited part of the aviation component, the result of jet strengthening by the angular nozzle is selected as a comparison group, and in each scheme, the jet parameters of the comparison group are the same as those of the jet nozzle.

TABLE 1 Water jet strengthening Experimental protocol

Fig. 5A and 5B show the residual stress distribution of different experimental schemes of the present invention and the control group, respectively, and it can be seen from the figure that the layer depth of the residual compressive stress and the residual compressive stress of the present invention are larger than that of the control group under the same water jet parameters. For example, when the jet angle is 20 degrees and the jet pressure is 50MPa, the residual compressive stress of the jet nozzle is about-180 MPa, the residual compressive stress of the control group is about-110 MPa, and the residual compressive stress of the jet nozzle is about 1.6 times of that of the control group, so that the strengthening effect of the jet nozzle for strengthening the surface of the limited part of the aviation component is better.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.

Claims

1. A jet nozzle for surface strengthening of a restricted area of an aerospace component, comprising:

2. The jet nozzle for aerospace component restricted surface peening of claim 1, wherein the entrance cavity is flared with a tapered diameter.

3. The jet nozzle for aerospace component restricted surface peening of claim 1, wherein the primary and secondary throats are each elongated cylindrical.

4. The jet nozzle for aerospace component restricted area surface peening of claim 3, wherein the primary throat and the secondary throat have an axial length ratio of 8: 1.

5. The jet nozzle for surface strengthening of restricted areas of aerospace components of claim 1, wherein the entrance structure comprises an entrance section, an entrance section and a throat section in sequence along an axial direction, the entrance port is located at the entrance section, the entrance cavity is located at the entrance section, and the primary throat is located at the throat section.

6. The jet nozzle for aircraft component restricted area surface peening of claim 5, wherein said sleeve is sleeved outside said throat section and in close proximity to said entrance section.

7. The jet nozzle for aerospace component restricted surface peening of claim 6, wherein a shim is disposed between the sleeve and the incident section.

8. The jet nozzle for aerospace component restricted area surface peening of claim 5, wherein the entrance section, the sleeve and the exit structure are bolted together.

9. The jet nozzle for aerospace component restricted surface peening of claim 1, wherein the exit structure has a conical protrusion on an end proximate the sleeve.

10. The jet nozzle for aerospace component restricted surface peening of claim 1, wherein the exit port is hemispherical.