A helicopter engine air inlet sand removal device for preventing axial fan blades from wearing out

Abstract

A helicopter engine air inlet sand removal device with wear-resistant axial fan blades includes a sand and dust separation device and a sand and dust discharge device. The sand and dust separation device includes a panel assembly and a vortex tube separator. The panel assembly forms a sand collection box and an air collection box. The vortex tube separator is arranged in the sand collection box. The sand collection box is provided with an air inlet and an exhaust hole. The tube body of the vortex tube separator is provided with a sand discharge channel connected to the sand collection box. Sand-laden air enters the vortex tube separator through the air inlet, and clean air enters the air collection box through the exhaust hole. The sand and dust discharge device includes an ejector sand discharge pipe, an air bleed pipe, an axial flow fan, a main air outlet pipe, and a cyclone separator. The ejector sand discharge pipe is connected to the sand collection box. A bypass port is provided on the side of the ejector sand discharge pipe and is connected to the air collection box through the air bleed pipe. The axial flow fan is installed in the air bleed pipe. A cyclone separator is provided between the axial flow fan and the air collection box. The air collection box is provided with a main air outlet. The present invention can prevent sand particles from wearing the fan and improve sand removal efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter engine air intake, and in particular relates to a helicopter engine air intake sand removal device for preventing axial flow fan blades from abrasion. Background Art

[0002] Due to their specialized uses and small size, helicopters are often used for fast, short-distance flights, with minimal requirements for flight sites. Helicopters frequently land in the wild and take off and land in diverse climates. These unique terrain and environments necessitate the installation of sand control devices at the engine inlet. These devices purify the air, reduce the sand content of the air entering the engine, and prevent sand particles from abrading the blades. Depending on the sand removal principle and location, they are generally categorized as vortex tube separators, integral particle separators, and barrier particle separators. Both vortex tube separators and integral particle separators utilize the principles of inertia, relying on gravity and centrifugal force to separate gas and solids. Vortex tube separators are separate components installed in front of the helicopter engine air intake, while integral particle separators are integral to the engine. Barrier particle separators differ from the previous two in that they utilize a fiber mesh material to bind airborne particles. Currently, the vortex tube separator is the most commonly used. As a separate device, it is easily disassembled and replaced, offers high separation efficiency, and is lightweight.

[0003] In addition to the air-solid separation mechanism, the sand removal system also includes a sand and dust discharge device. Currently, most helicopters use axial-flow fans. The rotating blades create a pressure differential to expel sand from the sand box to the outside. The axial-flow fan is located at the sand box outlet. Exhausting sand wears the blades, shortening the fan's lifespan and requiring regular replacement. Summary of the Invention

[0004] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a helicopter engine air inlet sand removal device with anti-wear axial fan blades, thereby avoiding the wear of sand particles on the fan, improving the sand removal efficiency, reducing the number of times the fan is replaced, and saving economic costs.

[0005] In order to achieve the above object, the present invention has the following technical solutions:

[0006] A helicopter engine air inlet sand removal device for preventing axial fan blade wear comprises a sand and dust separation device and a sand and dust discharge device; the sand and dust separation device comprises a panel assembly and a vortex tube separator, wherein the panel assembly forms a sand collection box and an air collection box separated from each other; the vortex tube separator is arranged in the sand collection box, and the sand collection box is provided with an air inlet and an exhaust hole; the tube body of the vortex tube separator is provided with a sand discharge channel connected to the sand collection box; sand-laden air is passed into the vortex tube separator through the air inlet, and clean air separated by the vortex tube separator is passed into the air collection box through the exhaust hole;

[0007] The sand and dust discharge device includes an ejector sand discharge pipe, an air bleed pipe, an axial flow fan, a main air outlet pipe and a cyclone separator. The ejector sand discharge pipe is connected to the sand collecting box. A bypass port is provided on the side of the ejector sand discharge pipe and is connected to the air collecting box through the air bleed pipe. The axial flow fan is installed in the air bleed pipe. A cyclone separator is provided between the axial flow fan and the air collecting box. A main air outlet is provided on the air collecting box, and the main air outlet of the air collecting box is connected to the air inlet of the helicopter engine through the main air outlet pipe.

[0008] Preferably, the panel assembly includes an upper panel, a middle partition panel, a lower panel and a peripheral side panel. The upper panel has several circular holes as air inlet holes, and the middle partition panel has several circular holes as air exhaust holes. The upper panel, the middle partition panel and the peripheral side panel form a sand collecting box, and the middle partition panel, the lower panel and the peripheral side panel form an air box.

[0009] Preferably, the upper panel has 9×9 evenly distributed circular holes as air inlet holes, the middle partition panel has 9×9 evenly distributed circular holes as exhaust holes at the air inlet hole positions corresponding to the upper panel, the number of the vortex tube separators is set to 9×9, and a vortex tube separator is connected between each pair of air inlet holes and exhaust holes.

[0010] Preferably, the panels of the sand collecting box and the air collecting box each extend forward and converge, and only leave a circular opening at the convergent end, which serves as a sand discharge port and a main air outlet, respectively; the ejector sand discharge pipe is connected to the circular opening of the sand collecting box, and the main air outlet pipe is connected to the circular opening of the air collecting box. A bypass port is provided on the side of the main air outlet pipe, and the air duct is connected between the main air outlet pipe and the bypass port of the ejector sand discharge pipe.

[0011] Preferably, the vortex tube separator consists of a vortex tube and a separation section; the vortex tube includes a swirl blade arranged inside a circular tube and a blade center body on which the swirl blade is installed, and the air inlet is above the swirl blade; the separation section is a trumpet-shaped diffuser main pipe, the diameter of which gradually increases from the air inlet to the exhaust, and there is a section of constant diameter at the exhaust; the inner diameter of the vortex tube is larger than the outer diameter at the air inlet of the separation section; the vortex tube is sleeved on the outside of the separation section, and the gap between the two forms a sand discharge channel; the center line of the vortex tube and the center line of the separation section are on the same straight line.

[0012] Preferably, both ends of the vortex tube and the separation section of the vortex tube separator are tightly connected to the air inlet and the exhaust hole of the sand collecting box respectively, and the vortex tube separator and the air inlet and the exhaust hole are on the same central axis.

[0013] Preferably, the ejector sand discharge pipe is a hollow structure, consisting of an inner tube and an outer tube, the inner tube is connected to the sand collecting box, the outer tube is connected to the panel of the sand collecting box, and an annular wind ring is provided in the gap between the inner tube and the outer tube; the length of the outer tube is greater than that of the inner tube, and the head of the outer tube extends from the head of the inner tube; a slit air outlet is provided in the middle of the inner tube; a Coanda surface is provided at a position close to the slit air outlet; and the bypass port is provided on the lower side of the outer tube.

[0014] Preferably, the cyclone separator is installed in the air duct; the air inlet pipe of the cyclone separator faces the inside of the air collecting box, the ash discharge pipe leads to the sand collecting box, and the exhaust pipe faces the axial flow fan.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects:

[0016] When a helicopter flies in an environment with a lot of sand and dust, sand-laden air is passed through the air inlet of the sand collecting box into the vortex tube separator, where the vortex tube separator separates the air from the sand and dust. The sand and dust enter the sand collecting box through the sand discharge channel of the vortex tube separator, and the clean air separated by the vortex tube separator enters the air collecting box through the exhaust hole of the sand collecting box. Under the action of the axial flow fan, a small amount of gas in the air collecting box is sucked into the air bleed pipe, and then enters the ejector sand discharge pipe after secondary filtration by the cyclone separator. According to the Bernoulli principle, the pressure difference generated will cause the sand and dust to be discharged through the ejector sand discharge pipe; the clean air is discharged from the main air outlet pipe for use by the helicopter engine. The sand discharge device of the present invention can reduce most of the sand and dust in the engine intake air, send the clean air into the helicopter engine, reduce the damage of the sand and dust to the engine, and extend the service life of the engine. The application of the bladeless fan principle of the present invention moves the centrifugal fan or axial flow fan located at the outlet of the sand discharge box in the traditional sand discharge device into the air intake duct. In addition, a cyclone separator is installed in front of the axial flow fan, which greatly reduces the wear of sand and dust on the fan blades, avoids frequent replacement of the fan, ensures the stability of the use of the device, and saves economic costs to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the external structure of a helicopter engine air inlet sand removal device for preventing axial fan blade wear according to an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the internal structure of a helicopter engine air inlet sand removal device for preventing axial fan blade wear according to an embodiment of the present invention;

[0019] Figure 3 A schematic cross-sectional view of a vortex tube separator according to an embodiment of the present invention.

[0020] In the accompanying drawings: 1-sand and dust separation device; 2-sand and dust discharge device; 11-panel assembly; 12-vortex tube separator; 21-injection sand discharge pipe; 22-air duct; 23-axial flow fan; 24-main air outlet pipe; 25-cyclone separator; 111-upper panel; 112-middle partition panel; 113-lower panel; 114-side panel; 115-sand collecting box; 116-air collecting box; 121-vortex tube; 122-separation section; 1211-swirl blade; 1212-blade center body; 1221-diffuser main flow pipe; 1222-sand discharge channel; 211-inner pipe; 212-outer pipe; 213-annular wind ring; 214-slit air outlet. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only applicable to the explanation of the present invention, and are not used to limit the scope of protection requested by the present invention.

[0022] like Figure 1 and Figure 2 As shown, an embodiment of the present invention shows a helicopter engine air inlet sand removal device for preventing axial fan blade wear, comprising a sand and dust separation device 1 and a sand and dust discharge device 2. The sand and dust separation device 1 comprises a panel assembly 11 and a vortex tube separator 12; the sand and dust discharge device 2 comprises an ejector sand discharge pipe 21, an air bleed pipe 22, an axial fan 23, a main air outlet pipe 24, and a cyclone separator 25. In one possible embodiment, the panel assembly 11 comprises an upper panel 111, an intermediate partition panel 112, a lower panel 113, and a peripheral panel 114. The upper panel 111 is provided with 9×9 evenly distributed circular holes for air intake by the vortex tube separator 12; the intermediate partition panel 113 is also provided with 9×9 evenly distributed circular holes for air exhaust by the vortex tube separator 12; and the intermediate partition panel 112 separates clean air from sand and dust. In this embodiment, a sand collecting box 115 is formed by the upper panel 111, the middle partition panel 112 and the peripheral side panels 114; and an air collecting box 116 is formed by the middle partition panel 112, the lower panel 113 and the peripheral side panels 114; and the air collecting box 116 is located below the sand collecting box 115.

[0023] The panels of the sand collecting box 115 and the air collecting box 116 of the embodiment of the present invention each extend forward and converge, leaving only one circular opening for each, which is used to discharge sand or exhaust respectively; the sand discharge device of the present invention has different structural shapes and different air intake directions according to the different air intake volumes of the engine. The circular opening can be set at the bottom of the sand collecting box 115, and the sand particles flow to the sand discharge port along the inclined surface of the convergent part due to the action of gravity. The vortex tube separator 12 is set between the upper panel 111 and the middle partition panel 112, and mainly consists of two parts: the vortex tube 121 and the separation section 122. Figure 3 As shown, the vortex tube 121 of this embodiment includes a swirl blade 1211 and a blade center body 1212 arranged in a circular tube at one end, and the upper channel of the swirl blade 1211 has an air inlet; the separation section 122 is a trumpet-shaped diffuser main pipe 1221, whose diameter gradually increases from the air inlet to the exhaust, and there is a section of constant diameter at the exhaust; the inner diameter of the vortex tube 121 is larger than the outer diameter of the separation section 122 at the air inlet; the vortex tube 121 is sleeved on the outside of the separation section 122, and the gap between the two forms a sand discharge channel 1222; the center line of the vortex tube 121 and the center line of the separation section 122 are on the same straight line. Sand-laden air enters the vortex tube 121 through the air inlet. Under the guidance of the swirl blades 1211, a rotating flow field is generated inside the vortex tube 121. Sand and dust with a density greater than that of the gas are thrown toward the wall of the vortex tube 121 by the inertial force in the rotating flow field, and collide with the wall, losing their original speed of movement. They spiral downward along with the airflow near the wall, pass through the sand discharge channel 1222, and enter the sand collecting box 115. Clean air enters the air collecting box 116 through the central diffuser main pipe 1221. In this embodiment, the number of vortex tube separators 12 is equal to the number of circular holes in the upper panel 111 and the middle partition panel 112; the diffuser main pipe 1221 is tightly connected to the circular holes in the middle partition panel 112 to prevent sand and dust in the sand collecting box 115 from entering the air collecting box 116 and affecting the separation efficiency.

[0024] The design of the ejector sand discharge pipe 21 in the embodiment of the present invention draws on the principle of a bladeless fan. It has a hollow structure and consists of an inner tube 211 and an outer tube 212. The inner tube 211 is connected to the circular opening of the sand collecting box 115, and the outer tube 212 is welded to the panel of the sand collecting box. The gap between the inner tube 211 and the outer tube 212 forms an annular wind circle 213; sand and dust can enter the sand discharge channel in the middle of the ejector sand discharge pipe 21 from the sand collecting box 115; an annular slit air outlet 214 is provided in the middle of the inner tube 211 of the ejector sand discharge pipe 21; a Coanda surface is provided close to the air outlet; and a bypass port is provided on the lower side of the outer tube 212 of the ejector sand discharge pipe 21.

[0025] In this embodiment of the present invention, one end of the bleed air duct 22 is connected to the bypass port of the ejector sand removal pipe 21, and the other end is connected to the air collection box 116. A cyclone separator 25 and an axial flow fan 23 are installed in the bleed air duct 22. The air inlet pipe of the cyclone separator 25 faces the entrance of the bleed air duct 22, the dust discharge pipe leads to the sand collection box 115, and the exhaust pipe faces the axial flow fan 23. The cyclone separator 25 can perform a secondary filtration on the gas about to flow through the axial flow fan 23, reducing wear on the fan blades. The filtered gas enters the annular air ring 213 of the ejector sand removal pipe 21, while the sand enters the sand collection box 115 through the dust discharge pipe. One end of the main air outlet pipe 24 is connected to the circular opening of the air collection box 116, and the other end is connected to the diffuser at the air intake of the helicopter engine.

[0026] The working process of the helicopter engine air inlet sand removal device for preventing axial fan blade wear according to the embodiment of the present invention is as follows:

[0027] When a helicopter flies in an environment with a high dust content, the engine suction forces the sand-laden gas to pass through the circular holes in the upper panel 111 and into the 9×9 evenly distributed vortex tube separators 12. The flow-guiding action of the swirl blades 1211 creates a rotating flow field inside the vortex tube 121. In this rotating flow field, the swirl blades 1211 cause the sand-laden gas to have both radial and tangential velocities. Sand particles, which have a density greater than that of air, gradually move toward the wall of the vortex tube 121 under the action of centrifugal force. After the sand particles collide with the wall of the vortex tube 121, they are unable to maintain their original velocity and therefore move downward under the action of gravity, entering the sand collecting box 115 through the sand discharge channel 1222. Clean air, on the other hand, enters the air collecting box 116 through the central diffuser main pipe 1221, thus completing the separation of gas and dust.

[0028] Under the action of the axial flow fan 23, a small portion of the clean air in the air collection box 116 that has undergone the first filtration is sucked into the air intake pipe 22. After completing the second filtration in the cyclone separator 25, it enters the annular air ring 213 between the inner tube 211 and the outer tube 212 of the ejector sand discharge pipe 21. This airflow is forced to be ejected at high speed from the slit air outlet 214 of the inner tube. Due to the presence of a Coanda surface near the air outlet, more surrounding air is driven toward the opening of the slit air outlet 214 (i.e., away from the sand collection box 115). The air radially outside the slit air outlet 214 is driven by the airflow at the air outlet to move away from the sand collection box 115, forming a negative pressure area in the sand discharge channel in the middle of the sand discharge pipe (based on the Bernoulli principle). As a result, the sand and dust in the sand collection box 115 are sucked into the sand discharge channel and discharged. Most of the clean gas in the gas collecting box 116 is transported to the engine for use after passing through the main gas outlet pipe 24.

[0029] The use of the helicopter engine air inlet sand removal device of the present invention can reduce most of the sand and dust in the inhaled gas, send clean gas into the helicopter engine, reduce the damage of sand and dust to the engine, and extend the life of the engine; based on the application of the bladeless fan principle, the centrifugal fan or axial flow fan located at the outlet of the sand discharge box in the traditional sand removal device is moved to the air bleed pipe 22, and a cyclone separator 25 is installed in front of the axial flow fan 23, which greatly reduces the wear of the fan blades by sand and dust, avoids frequent replacement of the fan, ensures the stability of the use of the device, and saves economic costs to a certain extent.

[0030] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A helicopter engine air inlet sand removal device for preventing axial fan blade wear, characterized by: The invention comprises a sand dust separation device (1) and a sand dust discharge device (2); the sand dust separation device (1) comprises a panel assembly (11) and a vortex tube separator (12); a sand collecting box (115) and an air collecting box (116) are formed by the panel assembly (11); the vortex tube separator (12) is arranged in the sand collecting box (115); an air inlet and an air outlet are provided on the sand collecting box (115); a tube body of the vortex tube separator (12) is provided with a sand discharge channel (1222) communicating with the sand collecting box (115); sand-containing air is passed into the vortex tube separator (12) through the air inlet; and clean air separated by the vortex tube separator (12) is passed into the air collecting box (116) through the air outlet. The sand and dust discharge device (2) comprises an ejector sand discharge pipe (21), an air bleed pipe (22), an axial flow fan (23), a main air outlet pipe (24) and a cyclone separator (25). The ejector sand discharge pipe (21) is connected to the sand collecting box (115). A bypass port is provided on the side of the ejector sand discharge pipe (21) and is connected to the air collecting box (116) through the air bleed pipe (22). The axial flow fan (23) is installed in the air bleed pipe (22). A cyclone separator (25) is provided between the axial flow fan (23) and the air collecting box (116). A main air outlet is provided on the air collecting box (116), and the main air outlet of the air collecting box (116) is connected to the air inlet of the helicopter engine through the main air outlet pipe (24).

2. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 1 is characterized by: The panel assembly (11) comprises an upper panel (111), a middle partition panel (112), a lower panel (113) and a peripheral side panel (114); the upper panel (111) is provided with a plurality of circular holes as air inlets, the middle partition panel (112) is provided with a plurality of circular holes as air outlets, the upper panel (111), the middle partition panel (112) and the peripheral side panel (114) form a sand collecting box (115), and the middle partition panel (112), the lower panel (113) and the peripheral side panel (114) form an air box (116).

3. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 2 is characterized by: The upper panel (111) is provided with 9×9 evenly distributed circular holes as air inlet holes, and the middle partition panel (112) is provided with 9×9 evenly distributed circular holes as air outlet holes at positions corresponding to the air inlet holes of the upper panel (111). The number of vortex tube separators (12) is set to 9×9, and a vortex tube separator (12) is connected between each pair of air inlet holes and air outlet holes.

4. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 1, characterized in that: The panels of the sand collecting box (115) and the air collecting box (116) respectively extend forward and converge, and only one circular opening is left at the convergent end, which serves as a sand discharge port and a main air outlet, respectively; the ejector sand discharge pipe (21) is connected to the circular opening of the sand collecting box (115), the main air outlet pipe (24) is connected to the circular opening of the air collecting box (116), a bypass port is opened on the side of the main air outlet pipe (24), and the air duct (22) is connected between the main air outlet pipe (24) and the bypass port of the ejector sand discharge pipe (21).

5. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 1 is characterized by: The vortex tube separator (12) consists of a vortex tube (121) and a separation section (122); the vortex tube (121) comprises a swirl blade (1211) arranged inside a section of a circular tube and a blade center body (1212) on which the swirl blade (1211) is installed, and the upper part of the swirl blade (1211) is an air inlet; the separation section (122) is a trumpet-shaped expansion main flow pipe (1221), the diameter of which gradually increases from the air inlet to the exhaust, and there is a section of constant diameter at the exhaust; the inner diameter of the vortex tube (121) is larger than the outer diameter of the separation section (122) at the air inlet; the vortex tube (121) is sleeved on the outside of the separation section (122), and the gap between the two forms a sand discharge channel (1222); the center line of the vortex tube (121) and the center line of the separation section (122) are on the same straight line.

6. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 5, characterized in that: The vortex tube (121) and the separation section (122) of the vortex tube separator (12) are tightly connected to the air inlet and the exhaust hole of the sand collecting box (115) respectively, and the vortex tube separator (12) and the air inlet and the exhaust hole are on the same central axis.

7. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 1, characterized in that: The ejector sand discharge pipe (21) is a hollow structure, consisting of an inner pipe (211) and an outer pipe (212); the inner pipe (211) is communicated with the sand collecting box (115); the outer pipe (212) is connected to the panel of the sand collecting box (115); an annular air ring (213) is provided in the gap between the inner pipe (211) and the outer pipe (212); the outer pipe (212) is longer than the inner pipe (211); the head of the outer pipe (212) extends from the head of the inner pipe (211); a slit air outlet (214) is provided in the inner pipe (211); a Coanda surface is provided at a position close to the slit air outlet (214); and the bypass port is provided on the lower side of the outer pipe (212).

8. The helicopter engine air inlet sand removal device for preventing axial fan blade wear according to claim 1, characterized in that: The cyclone separator (25) is installed in the air duct (22); the air inlet pipe of the cyclone separator (25) faces the inside of the air collecting box (116), the ash discharge pipe leads to the sand collecting box (115), and the exhaust pipe faces the axial flow fan (23).

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