A positive pressure air sandblasting nozzle

Abstract

The present application belongs to the field of sand swallowing test of aircraft engines, and particularly relates to a positive pressure air sandblasting nozzle. It comprises: a shell, a mandrel, a bushing and a guide cone. A housing cavity is arranged inside the shell, an outlet connected to the housing cavity is arranged at the front end of the shell, a mounting hole is arranged at the rear end, and a sand-gas mixing inlet and a compressed air inlet are respectively arranged on the side wall of the shell; the mandrel is installed in the housing cavity of the shell from the outlet, and the rear end of the mandrel passes through the mounting hole and is fixedly connected to the shell with a locking nut; the bushing is sleeved on the outside of the mandrel and is fixedly connected to the shell, an annular inner flow channel is formed between the bushing and the mandrel, and the inner flow channel is connected to the compressed air inlet, and an annular outer flow channel is formed between the bushing and the shell, and the outer flow channel is respectively connected to the sand-gas mixing inlet and the compressed air inlet; the guide cone is sleeved on the front end of the mandrel and is fixed with a locking nut. The present application can achieve uniform distribution of sand and dust weight, composition and particles in the entire intake cross section.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine sand swallowing test, and in particular relates to a positive-pressure air sandblasting nozzle. Background Art

[0002] Military aircraft often encounter severe sand and dust weather when taking off, landing, flying close to the ground or passing through desert areas. The engine often inhales sand or dust raised by natural wind, aircraft wake or floating in the air. The engine parts are affected by sand and dust erosion, which is prone to wear, rust or even damage, causing the actual working characteristics of the engine to deviate, seriously affecting the technical and tactical performance and safety of the engine. Experience has shown that after the engine inhales a large amount of sand and dust, the engine thrust is reduced, the fuel consumption rate is increased, the blades of various components are worn and even the aerodynamic surface changes.

[0003] According to the requirements of the "Engine Sand Swallowing Test" in the "General Specifications for Aviation Turboprop and Turboshaft Engines" (GJB 241A-2010) and the "General Specifications for Aviation Turboprop and Turboshaft Engines" (GJB242A-2018), in order to verify the working ability of the engine after swallowing sand and dust, the sand swallowing test is listed as one of the assessment items for military engine status appraisal. It stipulates that "the engine, including all accessories, should be able to work satisfactorily within the entire working range under ground environmental conditions with an air sand and dust concentration of 0.053g / m3." During the sand swallowing test of an aviation engine, sand and dust that meet the standard requirements and specifications need to be sprayed at the front end of the engine to simulate sand and dust conditions. When the engine is running, the sand and dust enter the flow channel together with the intake air, thereby assessing the environmental adaptability of the engine. In order to fully assess the sand swallowing ability of the engine's inner and outer linings, the sprayed sand and dust should be evenly distributed in the engine intake section.

[0004] At present, my country has carried out a lot of technical research and test verification work on turboshaft and turboprop engines, but has almost never carried out sand swallowing verification on turbojets and turbofan engines. In addition, the research on sand swallowing tests mainly focuses on the impact of sand and dust particles on engine performance, and there is little research on sand swallowing test equipment. As the core component of the sand swallowing test device, the sandblasting nozzle of the existing equipment mainly adopts a form similar to that used in the shot peening process. In order to achieve the uniform distribution requirements, multiple nozzles are evenly distributed along the circumference, and the sand and dust are ejected linearly from multiple nozzles at the same time and sucked into the engine. The nozzle structure of this structural form is simple and can ensure the smoothness of sand blasting, but the spray uniformity is poor, resulting in limited actual sand blasting coverage area when used for sand swallowing tests.

[0005] The sand swallowing test device in the prior art also has the following defects: in terms of technology, a) the sand used in the sand swallowing test is made of sand dust with various particle sizes. Since the test sand has many components, the density of each component varies greatly and the particle size span is large, during the storage and use of the sand dust, under the action of gravity, the larger and heavier particles are easy to settle at the bottom. Before the nozzle is sprayed, the sand dust and the compressed air are simply mixed once, and then quickly sprayed in a straight line, resulting in uneven radial distribution of the total amount of sand dust in the engine intake section and uneven distribution of sand dust particles with different particle sizes and components in the intake section; b) Most of the existing nozzle structures adopt the direct injection form, and the coverage area of ​​the sprayed sand dust is limited. When the engine is tested, the sand dust cannot evenly cover the engine intake section; c) when multiple groups of multiple nozzles are arranged along the circumferential direction, the sand dust is still unevenly distributed in the intake section due to the limitation of the number of nozzles. At the same time, too many nozzles are prone to produce intake distortion at the engine inlet, affecting the working stability of the engine. In terms of cost, the existing nozzles are assembled from multiple groups of nozzles, which increases the cost of production, installation, and maintenance. Therefore, on the premise of meeting the functions, it is necessary to take into account the economic requirements and reduce the additional costs caused by changes and maintenance. In terms of efficiency, the existing nozzles are greatly affected by the actual size of the test engine. Since the test engine's external dimensions are different from the intake cross-sectional diameter; the existing non-universal nozzles are difficult to meet the actual installation, testing, maintenance and other requirements, and the applicability is not high; therefore, when adapting the nozzle to the engine, it is necessary to configure multiple groups and sizes of nozzles. In addition, a special installation structure is required. The installation and debugging of the nozzle requires a lot of time, manpower and material resources, resulting in a long test implementation and maintenance cycle and low efficiency.

[0006] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0007] The purpose of the present application is to provide a positive pressure air sandblasting nozzle to solve at least one problem existing in the prior art.

[0008] The technical solution of this application is:

[0009] A positive pressure air sandblasting nozzle, comprising:

[0010] A shell, wherein a receiving cavity is arranged inside the shell, an outlet communicating with the receiving cavity is arranged at the front end of the shell, a mounting hole is arranged at the rear end, and a sand-air mixing inlet and a compressed air inlet are respectively arranged on the side wall of the shell;

[0011] A mandrel, the mandrel is installed in the accommodating cavity of the shell through the outlet, and the rear end of the mandrel passes through the mounting hole and is fixedly connected to the shell in cooperation with a locking nut;

[0012] A bushing, wherein the bushing is sleeved on the outer side of the mandrel and fixedly connected to the housing, an annular inner flow channel is formed between the bushing and the mandrel, the inner flow channel is communicated with the compressed air inlet, and an annular outer flow channel is formed between the bushing and the housing, the outer flow channel is communicated with the sand-air mixing inlet and the compressed air inlet respectively;

[0013] A guide cone is sleeved on the front end of the core shaft and fixed with a locking nut.

[0014] In at least one embodiment of the present application, a spiral guide vane is further included, and the spiral guide vane includes a first spiral guide vane arranged in the inner flow channel.

[0015] In at least one embodiment of the present application, the spiral guide vane includes a second spiral guide vane disposed in the outer flow channel.

[0016] In at least one embodiment of the present application, the spiral guide vane includes an inner ring, and a plurality of blades are evenly arranged on the outer side of the inner ring along the circumferential direction, and the angle between the blades and the axis is 45°.

[0017] In at least one embodiment of the present application, an adjustment gasket is provided between the guide cone and the core shaft.

[0018] In at least one embodiment of the present application, the guide cone includes multiple specifications, and the guide cones of various specifications have different tapers.

[0019] The invention has at least the following beneficial technical effects:

[0020] The positive pressure air sandblasting nozzle of the present application adopts multiple mixing, dual flow channels, guide cone and other designs to solve the problem of limited sandblasting coverage area. The total amount of sandblasting is evenly distributed, sand and dust of different particle sizes are evenly distributed, and the sand and dust sprayed from the nozzle are evenly distributed in the air intake section, and the sand and dust coverage area can be adjusted. The present application can effectively provide a uniform distribution environment, and the weight, composition, and particles of the sand and dust are evenly distributed in the entire air intake section. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of a positive pressure air sandblasting nozzle according to one embodiment of the present application;

[0022] Figure 2 is a schematic diagram of a spiral guide vane according to an embodiment of the present application;

[0023] Figure 3 It is a schematic diagram of a guide cone according to an embodiment of the present application.

[0024] in:

[0025] 1-housing; 2-core shaft; 3-bushing; 4-inner flow channel; 5-outer flow channel; 6-guide cone; 7-spiral guide vane; 71-inner ring; 72-blade; 8-adjusting gasket. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0027] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0028] The following is combined with Figures 1 to 3 This application is described in further detail.

[0029] The present application provides a positive pressure air sandblasting nozzle, comprising: a housing 1 , a core shaft 2 , a bushing 3 and a guide cone 6 .

[0030] Specifically, Figure 1As shown, the shell 1 is the main load-bearing structure of the nozzle and the installation base of other parts. It is mainly used to fix the core shaft 2 and the bushing 3 and constitute the outer wall of the nozzle. A accommodating cavity is arranged inside the shell 1. The front end of the shell 1 is provided with an outlet connected to the accommodating cavity, and the rear end is provided with a mounting hole. The side walls of the shell 1 are respectively provided with a sand-gas mixing inlet and a compressed air inlet, wherein the sand-gas mixing inlet and the compressed air inlet are arranged directly above the nozzle shell 1, the sand-gas mixing inlet is located in front of the compressed air inlet, and the outlet connected to the accommodating cavity is arranged directly in front of the nozzle shell 1 as a sandblasting outlet. The core shaft 2 is installed in the accommodating chamber of the shell 1 from the outlet, and the rear end of the core shaft 2 passes through the mounting hole and is fixedly connected to the shell 1 with a locking nut; the bushing 3 is sleeved on the outer side of the core shaft 2 and is fixedly connected to the mounting portion arranged inside the shell 1; the shell 1, the core shaft 2 and the bushing 3 divide the accommodating chamber inside the shell 1 into two inner and outer medium flow areas, wherein an annular inner flow channel 4 is formed between the bushing 3 and the core shaft 2, and the inner flow channel 4 is connected to the compressed air inlet, and an annular outer flow channel 5 is formed between the bushing 3 and the shell 1, and the outer flow channel 5 is respectively connected to the sand-gas mixing inlet and the compressed air inlet; the guide cone 6 is sleeved on the front end of the core shaft 2 and is fixed with a locking nut.

[0031] In the preferred embodiment of the present application, a spiral guide vane 7 is fixed in each of the inner flow channel 4 and the outer flow channel 5 to control the flow field direction of the inner and outer flow channels. The spiral guide vanes 7 include a first spiral guide vane arranged in the inner flow channel 4 and a second spiral guide vane arranged in the outer flow channel 5. The first spiral guide vane is integrally sleeved on the core shaft 2 and fixed by welding, and the second spiral guide vane is integrally sleeved on the bushing 3 and fixed by welding. Figure 2 As shown, the spiral guide vane 7 includes an inner ring 71, and a plurality of blades 72 are evenly arranged on the outer side of the inner ring 71 along the circumferential direction. The angle between the blades 72 and the axis of the spiral guide vane 7 is 45°, and a spiral flow field channel is formed between adjacent blades.

[0032] In the preferred embodiment of the present application, a guide cone 6 structure is provided at the outlet of the nozzle, such as Figure 3 As shown, the guide cone 6 is installed on the mandrel 2, and an adjustment gasket 8 is provided between the guide cone 6 and the mandrel 2. The axial positioning of the guide cone 6 is adjusted by the adjustment gasket 8 and fixed by a locking nut, so that the guide cone 6 is easy to adjust and install. Advantageously, in this embodiment, the guide cone 6 includes multiple specifications, and the guide cone 6 of each specification has a different taper. In actual use, the appropriate guide cone 6 can be selected by air pressure to control the actual sandblasting distribution.

[0033] The positive pressure air sandblasting nozzle of the present application is provided with a sand-gas mixing inlet and a separate compressed air inlet, and the compressed air is a stable air source with adjustable pressure. Part of the air entering from the separate compressed air inlet enters the inner flow channel 4, and part enters the outer flow channel 5. The inner and outer flow channels adopt an annular structure, and the air generates a circumferential flow field in the inner and outer flow channels. Then, the air flows through the spiral guide vane 7, which can rectify the flow field and change the direction of the flow field at the same time, so that the inner and outer flow channels generate a uniform spiral flow field. In the sand-gas mixing inlet, one branch is a sand and dust branch, and one branch is a compressed air branch. The sand and dust are mixed with the compressed air for the first time at the nozzle inlet. After the first mixing, the sand and dust enter the outer flow channel 5 of the nozzle. Affected by the spiral airflow of the outer flow channel, the sand and dust are mixed for the second time, and sand and dust particles of different particle sizes are fully mixed in the annular outer flow channel 5, which solves the problem that large particles of sand and dust are deposited downward, resulting in uneven distribution of sand and dust particle sizes. The sand and dust are affected by the spiral flow field in the outer flow channel, filling the annular outer flow channel 5. At the nozzle outlet, the sand and dust are affected by the spiral flow field of the inner flow channel 4, and are uniformly ejected outward. The sand and dust are evenly distributed in the air intake section. The nozzle outlet is a guide cone 6 structure. Under the action of compressed air, the sand and dust flow along the cone surface and diffuse outward over a large area, greatly increasing the coverage area of ​​the sand and dust ejected from a single nozzle. The coverage area of ​​the ejected sand and dust can be changed by controlling the pressure of the compressed air and the angle of the guide cone, realizing stepless regulation and wide applicability.

[0034] The positive pressure air sandblasting nozzle of this application,

[0035] (a) Two inner and outer annular flow channels are designed inside the nozzle, and a spiral guide vane structure is used to control the direction of the compressed air flow field to form a spiral airflow, so that the sand and dust are ejected evenly along the circumferential direction, achieving uniform distribution of sand and dust in the air intake section;

[0036] (b) The sand and dust are mixed with compressed air for the first time at the nozzle inlet and for the second time in the annular outer flow channel, so that sand and dust particles of various sizes are fully mixed, and the problem of large-size sand and dust being deposited at the bottom, resulting in uneven distribution of sand and dust particle sizes in the air intake section, is solved;

[0037] (c) A guide cone structure is designed at the nozzle. The sand and dust are diffused and sprayed outward along the cone surface under the action of compressed air. The coverage cross-sectional diameter is large. A single nozzle can achieve large-area coverage of sand and dust. The actual sandblasting distribution is controlled by changing the guide cone angle and matching the air pressure. An adjustment gasket is installed between the guide cone and the mandrel. The sandblasting outlet area is controlled by changing the thickness of the gasket to achieve the purpose of adjusting the sand and dust coverage area.

[0038] (d) The coverage area of ​​the sprayed sand and dust can be changed by controlling the pressure of the compressed air and the angle of the guide cone, thereby achieving stepless regulation of the coverage area of ​​the sand and dust. This allows sand swallowing tests to be carried out on various types of aircraft engines, and has a wide range of applicability.

[0039] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A positive pressure air blasting nozzle, characterized in that: include: A shell (1), wherein a receiving cavity is arranged inside the shell (1), an outlet communicating with the receiving cavity is provided at the front end of the shell (1), a mounting hole is provided at the rear end, and a sand-air mixing inlet and a compressed air inlet are respectively provided on the side wall of the shell (1); A core shaft (2), the core shaft (2) being installed in the accommodating cavity of the shell (1) through the outlet, and the rear end of the core shaft (2) passing through the installation hole and then being fixedly connected to the shell (1) in cooperation with a locking nut; A bushing (3), the bushing (3) is sleeved on the outer side of the core shaft (2) and is fixedly connected to the housing (1), an annular inner flow channel (4) is formed between the bushing (3) and the core shaft (2), the inner flow channel (4) is communicated with the compressed air inlet, and an annular outer flow channel (5) is formed between the bushing (3) and the housing (1), the outer flow channel (5) is respectively communicated with the sand-air mixing inlet and the compressed air inlet; A guide cone (6) is sleeved on the front end of the core shaft (2) and fixed with a locking nut.

2. The positive pressure air sandblasting nozzle according to claim 1, characterized in that: It also comprises a spiral guide vane (7), wherein the spiral guide vane (7) comprises a first spiral guide vane arranged in the inner flow channel (4).

3. The positive pressure air blasting nozzle according to claim 2, characterized in that: The spiral guide vane (7) comprises a second spiral guide vane arranged in the outer flow channel (5).

4. The positive pressure air blasting nozzle according to claim 3, characterized in that: The spiral guide vane (7) comprises an inner ring (71), a plurality of blades (72) are evenly arranged along the circumferential direction on the outer side of the inner ring (71), and the angle between the blades (72) and the axis is 45°.

5. The positive pressure air sandblasting nozzle according to claim 1, characterized in that: An adjusting gasket (8) is provided between the guide cone (6) and the core shaft (2).

6. The positive pressure air sandblasting nozzle according to claim 4, characterized in that: The guide cone (6) includes multiple specifications, and the guide cone (6) of each specification has a different taper.

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