Tandem counterflow grid device

Abstract

A tandem counter-flow grid device is formed by arranging a plurality of tandem counter-flow grid units in a circumferential direction, each of the plurality of tandem counter-flow grid units including a plurality of grid inlet ribs located on an inlet side of the tandem counter-flow grid unit, and a plurality of grid outlet ribs located on an outlet side of the tandem counter-flow grid unit, an outlet end surface of the plurality of grid inlet ribs and an inlet end surface of the plurality of grid outlet ribs being spaced apart in a flow passage height direction and having a width in a reference line direction. With the tandem counter-flow grid device, a boundary layer separation phenomenon at the time of airflow deflection can be improved.

Description

Technical Field

[0001] This invention relates to a tandem thrust reverser grid device, and more specifically, to a tandem thrust reverser grid device applicable to the field of engine nacelle thrust reverser design for aircraft engines to provide reverse thrust during aircraft landing. Background Technology

[0002] Currently, most airline passenger aircraft use equal-thickness grid-type thrust reversers to achieve thrust reversal, thereby shortening landing distance. Generally speaking, thrust reversers, within the confined space of the engine nacelle, force a significant airflow deflection, which can easily lead to large-scale boundary layer separation within the flow channel. This results in substantial flow losses and channel blockage, ultimately reducing the aerodynamic performance of the thrust reversers.

[0003] When a fluid flows over the wall of an object, due to the influence of the fluid and viscosity on the wall, a thin layer with a gradually increasing velocity along the normal direction of the object's surface will appear close to the wall. This thin layer with a velocity from 0 to 99% of the mainstream velocity is generally called the boundary layer.

[0004] Furthermore, the distance from the surface of the object to the boundary layer boundary along the normal direction is called the boundary layer thickness. This boundary layer thickness gradually increases as the fluid flows a distance across the object's surface. This is because the fluid layer immediately adhering to the boundary layer is affected by the viscosity of the fluid within the boundary layer, gradually slowing down and becoming part of the boundary layer fluid.

[0005] Boundary layer separation refers to the phenomenon where fluid within the boundary layer flows backward and detaches from the surface of an object. The internal cause of this separation is fluid viscosity, while the external cause is the adverse pressure gradient that occurs when flowing along a curved surface.

[0006] Within the compressive gradient section, the viscosity within the boundary layer slows down the fluid, but the compressive effect accelerates the fluid within the boundary layer, resulting in an overall accelerated fluid movement within the boundary layer.

[0007] Within the adverse pressure gradient section, the fluid slows down due to the combined effects of the viscosity of the boundary layer and the adverse pressure. The velocity of the bottom layer of the boundary layer decreases rapidly. After the boundary layer separation point, the fluid at the bottom layer of the boundary layer flows backward under the adverse pressure. The fluid flowing backward meets the fluid flowing downstream at the boundary layer separation point, causing the boundary layer to arch up and detach from the object surface. It is then swept away by the mainstream, forming a large number of vortices, thus forming fluid boundary layer separation.

[0008] If boundary layer separation occurs, the airflow becomes unstable and blocks the flow channels, reducing the effective flow area and consequently decreasing the engine's intake air volume. Furthermore, boundary layer separation exacerbates flow non-uniformity, increasing losses within the channels and reducing engine performance.

[0009] Therefore, in general, by improving the aerodynamic shape design of the grille or by adopting flow control measures to control boundary layer separation, flow losses can be reduced, the aerodynamic performance of the thrust reverser grille can be improved, and thrust reverser efficiency can be increased. This helps the engine achieve the required thrust reverser force at lower speeds, thereby improving fuel economy.

[0010] In the past, methods such as extending the channel length, adding flow guiding devices, and adding deformation adjustment devices were commonly used to control grid flow separation. For example, Boeing's patent document US1471824 proposed adding a retractable flow guiding device to the leading edge of the grid to improve grid separation.

[0011] Specifically, the aircraft thrust reverser system disclosed in patent document US1471824 includes a fan duct with a leading edge, a grid positioned to guide gas outward from the fan duct to generate reverse thrust, and flow separation suppressor blades positioned within the fan duct near the leading edge, wherein the flow separation suppressor blades guide gas toward the grid. When the thrust reverser is engaged, the grid extends, positioning the flow separation suppressor blades near the leading edge upstream of the grid, guiding airflow through the flow separation suppressor blades into the grid.

[0012] However, existing methods for improving flow separation, such as extending the channel length, adding flow guiding devices, and adding deformation adjustment devices, all lead to more complex structures and increased weight, which in turn reduces the aerodynamic performance of the aircraft.

[0013] Therefore, how to provide a device that can improve flow separation without increasing structural complexity or weight has become an urgent technical problem to be solved. Summary of the Invention

[0014] This disclosure is made to solve the above-mentioned technical problems, and its purpose is to provide a tandem push bar grid device that can effectively control boundary layer separation with a simple structure.

[0015] To achieve the purpose of this disclosure, a tandem push-back grid device is provided, wherein the tandem push-back grid device is composed of a plurality of tandem push-back grid units arranged in a circumferential direction, wherein each of the plurality of tandem push-back grid units includes: a plurality of grid inlet ribs located on the inlet side of the tandem push-back grid unit; and a plurality of grid outlet ribs located on the outlet side of the tandem push-back grid unit, wherein the outlet end faces of the plurality of grid inlet ribs and the inlet end faces of the plurality of grid outlet ribs are spaced apart in the flow channel height direction and have a width in the baseline direction.

[0016] Based on the configuration described above, by dividing the grid ribs that guide the airflow in the tandem reverse-thrust grid unit into two ribs, namely the grid inlet rib and the grid outlet rib, the boundary layer separation phenomenon caused by the previous large deflection of airflow achieved by a single grid rib can be improved.

[0017] Preferably, each of the plurality of tandem push-back grid units further includes a grid unit side plate, which spacees the plurality of tandem push-back grid units apart from each other and provides mounting space for the plurality of grid inlet ribs and the plurality of grid outlet ribs.

[0018] Preferably, each of the plurality of tandem reverse-push grid units further includes a grid unit front plate and a grid unit tail plate, wherein the plurality of grid inlet ribs and the plurality of grid outlet ribs are located between the grid unit front plate and the grid unit tail plate.

[0019] As described above, by arranging multiple grid inlet ribs and multiple grid outlet ribs between the front plate and the rear plate of the grid unit and installing them on the side plate of the grid unit, the tandem reverse-push grid units can be formed into a whole, thereby facilitating the manufacture and installation of the tandem reverse-push grid device.

[0020] Preferably, the plurality of grille inlet ribs, the plurality of grille outlet ribs, the grille unit front plate, and the grille unit tail plate are formed in an airfoil shape.

[0021] Based on the above-described configuration, by designing it in an airfoil shape, it is easy to guide the airflow, thereby making the deflection of the airflow easier.

[0022] Preferably, the plurality of grille inlet ribs and the plurality of grille outlet ribs are arranged at equal intervals between the front plate of the grille unit and the tail plate of the grille unit.

[0023] Preferably, the inlet faces of the plurality of grille inlet ribs, the front plate of the grille unit, and the tail plate of the grille unit are located on the same straight line, and the outlet faces of the plurality of grille outlet ribs, the front plate of the grille unit, and the tail plate of the grille unit are located on the same straight line.

[0024] Based on the configuration described above, the manufacture of the tandem reverse-pushing grid unit is facilitated, and the operation is simple and convenient.

[0025] Preferably, the plurality of grille inlet ribs are arranged such that the inlet end face has an air intake angle relative to the inlet side baseline, and the plurality of grille outlet ribs are arranged such that the outlet end face has an air outlet angle relative to the outlet side baseline.

[0026] Preferably, the aforementioned air intake angle and air outlet angle are obtuse angles.

[0027] According to the configuration described above, by designing the aforementioned air inlet angle and air outlet angle as obtuse angles, it is more conducive to the flow of air into the tandem thrust grid unit and the flow of air out of the tandem thrust grid unit.

[0028] Preferably, the inlet ribs of the grille are arranged such that the angle at the outlet end face is the outflow angle, and the outlet ribs of the grille are arranged such that the angle at the inlet end face is the inflow angle.

[0029] Preferably, the outflow angle and the inflow angle are acute angles.

[0030] As described above, by designing the outflow angle and the inflow angle as acute angles, it is possible for the airflow to continue flowing along the grid outlet rib after passing through the grid inlet rib, thereby facilitating the deflection of the airflow.

[0031] Preferably, the gas from the engine enters the tandem thrust reverser grid unit through the grid unit inlet, and after passing through the plurality of grid inlet ribs and the plurality of grid outlet ribs in sequence, flows out of the tandem thrust reverser grid unit through the grid unit outlet.

[0032] Based on the above configuration, by passing the airflow sequentially through the grid inlet rib and the grid outlet rib, the airflow is deflected through two layers of grid ribs, which can improve the boundary layer separation phenomenon caused by the previous method of deflecting the airflow with a single layer of grid ribs.

[0033] Preferably, after the gas from the engine flows to the outlet end face via the front and rear blade profiles of the grille inlet rib, a small portion of the airflow flows out through the gap between the grille inlet rib and the grille outlet rib, while most of the airflow flows out along the front and rear blade profiles of the grille outlet rib.

[0034] As described above, by forming a channel for airflow between the grid inlet rib and the grid outlet rib, the reverse airflow flowing through the channel can be accelerated, thereby reducing the boundary layer thickness and slowing down separation. Attached Figure Description

[0035] In view of the above objectives, the technical features of the present invention are clearly described in the following technical solutions, and its advantages are apparent from the following detailed description with reference to the accompanying drawings, which illustrate preferred embodiments of the invention by way of example, without limiting the scope of the inventive concept.

[0036] Figure 1 This is a schematic diagram of the overall structure of an engine nacelle equipped with the tandem thrust reverser grid device of the present invention.

[0037] Figure 2 This is a schematic diagram of the arrangement of an engine nacelle equipped with the tandem thrust reverser grid device of the present invention on an aircraft.

[0038] Figure 3A This is a front view of the tandem reverse-thrust grid device of the present invention. Figure 3B The present invention relates to a tandem reverse-thrust grid device. Figure 3A A cross-sectional view at line AA. Figure 3C The tandem reverse-thrust grid device of the present invention Figure 3A An enlarged view of the rectangular frame portion.

[0039] Figure 4 It is Figure 3C An enlarged schematic diagram showing a portion of the tandem reverse-propagation grid unit.

[0040] Figure 5 This is a comparison diagram of the external appearance of the tandem thrust grid device of the present invention and a conventional thrust reverser device.

[0041] Figure 6A This is a Mach number cloud diagram of the tandem reverse-thrust grid device of the present invention. Figure 6B This is a Mach number cloud map of a previous thrust reverser device.

[0042] Figure 7 This is a performance comparison diagram between the tandem thrust grid device of the present invention and conventional thrust reverser devices. Symbol Explanation

[0043] 1. Tandem reverse-thrust grid device; 11 tandem thrust grid units; 11a grille inlet ribs; 11b grille outlet rib; 11c grille unit front panel; 11d grille unit tailgate; 11e grille unit side panel; 111. Grid unit entrance; 112 Grille unit outlet; 11a1, 11b1, 11c1, 11d1 inlet faces; 11a2, 11b2, 11c2, 11d2 outlet faces; 11a3, 11b3, 11c3, 11d3 front blade profiles; 11a4, 11b4, 11c4, 11d4 rear blade profiles; H-channel height; L-pitch; β1 intake angle; β2 exhaust angle; β12 outflow angle; β 21 Inflow angle; d x width; d h interval; 2. Engine nacelle; 3. Hanging components; 4. Wings; 5. Fuselage. Detailed Implementation

[0044] Various embodiments of the invention will now be described in detail, examples of which are illustrated in the accompanying drawings. Although the invention has been described in conjunction with exemplary embodiments, it should be understood that this specification is not intended to limit the invention to the exemplary embodiments described below. Rather, the invention is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0045] The following is for reference Figure 1 and Figure 2 The arrangement of the tandem reverse-push grid device 1 of the present invention will be described. Figure 1 This is a schematic diagram showing the overall structure of the engine nacelle 2 equipped with the tandem thrust reverser grid device 1 of the present invention. Figure 2 This is a schematic diagram of the arrangement of the engine nacelle 2 equipped with the tandem thrust reverser grid device 1 of the present invention on an aircraft.

[0046] like Figure 1 As shown, the tandem thrust reverser grid device 1 of the present invention is integrated inside the outer casing of the engine nacelle 2 and is installed together with the engine nacelle 2 below the sling 3, and the sling 3 is connected to the wing 4 of the aircraft as a whole, thereby installing the engine nacelle 2 equipped with the tandem thrust reverser grid device 1 below the wing 4 of the aircraft.

[0047] The aforementioned tandem thrust reverser grid device 1 is embedded inside the outer casing of the aircraft's engine nacelle 2, and more specifically, is arranged behind the aircraft's engine fan. Therefore, air from the outside enters the engine through the suction effect of the fan, and is then discharged to the outside environment through the aforementioned tandem thrust reverser grid device 1.

[0048] During the landing process, the thrust reverser integrated in the nacelle 2 is opened, and the blocker door blocks the bypass flow passage, so that the airflow passing through the fan is ejected obliquely forward from the thrust reverser grille, generating reverse thrust that helps the aircraft decelerate and stop. Moreover, since the aforementioned airflow is discharged to the outside through the tandem thrust reverser grille device 1, the occurrence of boundary layer separation can be suppressed through the tandem thrust reverser grille device 1, flow passage loss is reduced, and thrust reverser efficiency is improved.

[0049] In addition, as shown in Figure 2 , the aforementioned wing 4 is mounted on the fuselage 5 of the aircraft, so that the nacelle 2 equipped with the tandem thrust reverser grille device 1 is mounted on the fuselage 5 of the aircraft.

[0050] More specifically, two aforementioned nacelles 2 are symmetrically arranged on both sides of the fuselage 5 of the aircraft, and the nacelles 2 are used for integrating the engine and connecting to the aircraft, so as to more desirably provide the thrust for propelling the aircraft forward and the reverse thrust for stopping the aircraft.

[0051] Hereinafter, referring to Figures 3A-3C , the overall structure of the tandem thrust reverser grille device 1 of the present invention will be described.

[0052] Figure 3A is a front view of the tandem thrust reverser grille device 1 of the present invention, Figure 3B is a view of the tandem thrust reverser grille device 1 of the present invention Figure 3A a cross-sectional view taken along line AA, Figure 3C is an enlarged schematic view of the rectangular frame portion of the Figure 3A tandem thrust reverser grille device 1 of the present invention.

[0053] As shown in Figure 3A , the tandem thrust reverser grille device 1 of the present invention is composed of a plurality of layers of tandem thrust reverser grille units 11.

[0054] More specifically, as shown in Figure 3B , the aforementioned plurality of layers of tandem thrust reverser grille units 11 are arranged circumferentially along the nacelle 2, thereby constituting the tandem thrust reverser grille device 1 of the present invention.

[0055] In addition, with reference to Figure 3C , it can be seen that each of the aforementioned plurality of layers of tandem thrust reverser grille units 11 includes a plurality of grille inlet ribs 11a, a plurality of grille outlet ribs 11b, a grille unit front plate 11c, a grille unit tail plate 11d, and a grille unit side plate 11e.

[0056] In the tandem reverse-push grid unit 11, the plurality of grid inlet ribs 11a and the plurality of grid outlet ribs 11b are arranged between the front plate 11c and the rear plate 11d of the grid unit, and the plurality of grid inlet ribs 11a, the plurality of grid outlet ribs 11b, the front plate 11c and the rear plate 11d of the grid unit are all mounted on the side plate 11e of the grid unit.

[0057] like Figure 3C As shown, the plurality of grille inlet ribs 11a respectively include an inlet end face 11a1, an outlet end face 11a2, a front blade profile 11a3, and a rear blade profile 11a4; the plurality of grille outlet ribs 11b respectively include an inlet end face 11b1, an outlet end face 11b2, a front blade profile 11b3, and a rear blade profile 11b4; the grille unit front plate 11c includes an inlet end face 11c1, an outlet end face 11c2, a front blade profile 11c3, and a rear blade profile 11c4; and the grille unit tail plate 11d includes an inlet end face 11d1, an outlet end face 11d2, a front blade profile 11d3, and a rear blade profile 11d4.

[0058] exist Figure 3C In the example shown, the front plate 11c and the rear plate 11d of the grille unit are formed with the same airfoil shape, the plurality of grille inlet ribs 11a and the plurality of grille outlet ribs 11b are also formed with the same airfoil shape, and the grille inlet ribs 11a and the grille outlet ribs 11b have the same deflection angle relative to the axial direction.

[0059] However, the present invention is not limited thereto. The airfoil shapes of the front plate 11c and the tail plate 11d of the above-mentioned grid unit may also be different. The airfoil shapes of the plurality of grid inlet ribs 11a and the plurality of grid outlet ribs 11b may also be different. Furthermore, the deflection angles of the grid inlet ribs 11a and the grid outlet ribs 11b relative to the axial direction may also be different, as long as they are suitable for suppressing boundary layer separation.

[0060] Here, "airfoil shape" is a common term in the aviation field, indicating that the surface of the object can be an arc shape with curvature, a straight shape with zero curvature, or a shape composed of arc-shaped and straight segments.

[0061] The grid inlet rib 11a and grid outlet rib 11b of each of the above-mentioned multiple tandem reverse-push grid units 11 may be arranged in the same or different positions relative to the grid unit side plate 11e.

[0062] When the grid inlet rib 11a and grid outlet rib 11b of each of the above-mentioned multiple tandem reverse grid units 11 are arranged in a staggered manner relative to the grid unit side plate 11e, boundary layer separation can be suppressed more effectively.

[0063] Here, the connecting line between the inlet end face 11c1 of the front plate 11c of the above-mentioned grille unit and the inlet end face 11d1 of the tail plate 11d of the above-mentioned grille unit is set as the inlet side reference line, and the connecting line between the outlet end face 11c2 of the front plate 11c of the above-mentioned grille unit and the outlet end face 11d2 of the tail plate 11d of the above-mentioned grille unit is set as the outlet side reference line.

[0064] The aforementioned plurality of grille inlet ribs 11a are respectively mounted on the grille unit side plate 11e such that the inlet end face 11a1 is located on the inlet side reference line, and the aforementioned plurality of grille outlet ribs 11b are respectively mounted on the grille unit side plate 11e such that the outlet end face 11b2 is located on the outlet side reference line.

[0065] Furthermore, the portion between two adjacent grid inlet ribs 11a and grid unit side plate 11e constitutes grid unit inlet 111, and the portion between two adjacent grid outlet ribs 11b and grid unit side plate 11e constitutes grid unit outlet 112.

[0066] Gas from the engine enters the tandem thrust reverser grid unit 11 through the grid unit inlet 111, and after passing through the plurality of grid inlet ribs 11a and the plurality of grid outlet ribs 11b in sequence, it flows out of the tandem thrust reverser grid unit 11 through the grid unit outlet 112.

[0067] The following is for reference Figure 4 The specific structure of the tandem reverse-push grid unit 11 of the present invention will be described. Figure 4 It is Figure 3C An enlarged schematic diagram showing a portion of the tandem reverse-propagation grid unit 11.

[0068] like Figure 4 As shown, the aforementioned tandem reverse-push grid unit 11 has a flow channel height H, which is the distance between the inlet end face 11a1 of the grid inlet rib 11a and the outlet end face 11b2 of the grid outlet rib 11b.

[0069] The aforementioned plurality of grid inlet ribs 11a and the aforementioned plurality of grid outlet ribs 11b are arranged at equal intervals with a grid spacing L, wherein the grid spacing L is the distance between the inlet end faces 11a1 of the plurality of grid inlet ribs 11a or between the outlet end faces 11b1 of the plurality of grid outlet ribs 11b.

[0070] By rationally designing the flow channel height H and grid pitch L of the aforementioned tandem reverse-thrust grid unit 11, the overall performance of the tandem reverse-thrust grid device 1 can be optimized.

[0071] In addition, the aforementioned multiple grille inlet ribs 11a are arranged such that the angle between the inlet end face 11a1 and the inlet side reference line is the air intake angle β1, and the aforementioned multiple grille outlet ribs 11b are arranged such that the angle between the outlet end face 11b1 and the outlet side reference line is the air outlet angle β2.

[0072] By adjusting the inlet angle β1 of the grille inlet rib 11a and the outlet angle β2 of the grille outlet rib 11b, the inflow and outflow angles of the airflow can be effectively controlled as needed.

[0073] Furthermore, the aforementioned plurality of grille inlet ribs 11a and the aforementioned plurality of grille outlet ribs 11b are deflected at a certain angle, and the angle at the outlet end face 11a2 of the grille inlet rib 11a is the outflow angle β of the airflow flowing out of the grille inlet rib 11a. 12 The angle at the inlet end face b1 of the aforementioned grille outlet rib 11b is the inflow angle β of the airflow flowing in along the grille outlet rib 11b. 21 .

[0074] By adjusting the aforementioned outflow angle β 12 and the aforementioned inflow angle β 21 It can effectively control the airflow turning angle of the inlet rib 11a and outlet rib 11b of the grid, and achieve the deflection of the reverse airflow through multiple tandem reverse grid units 11, which can effectively reduce the boundary layer thickness and thus reduce flow loss.

[0075] In addition, such as Figure 4 As shown, the distance in the flow channel height direction between the outlet end face 11a2 of each of the plurality of grid inlet ribs 11a and the inlet end face 11b1 of each of the plurality of grid outlet ribs 11b is an interval d. h The distance along the baseline is the width d. x .

[0076] Air from the outside flows into the engine due to the suction effect of the engine fan, and then flows into the tandem thrust reverser grid unit 11 of the tandem thrust reverser grid device 1 through the grille inlet rib 11a. After the airflow flows to the outlet end face 11a2 through the front blade profile 11a3 and the rear blade profile 11a4 of the grille inlet rib 11a, a small part of the airflow flows out through the gap between the grille inlet rib 11a and the grille outlet rib 11b, and most of the airflow flows out along the front blade profile 11b3 and the rear blade profile 11b4 of the grille outlet rib 11b.

[0077] Therefore, by rationally designing the relative positions of the grille inlet rib 11a and the grille outlet rib 11b, for example by adjusting the aforementioned interval d, h and the width d mentioned above x This can accelerate the reverse airflow flowing through the gap, thereby reducing the boundary layer thickness and slowing down separation. On the other hand, it can separate the tail end of the grid inlet rib 11a and the boundary layer from the grid outlet rib 11b, thereby effectively controlling the boundary layer growth.

[0078] Furthermore, preferably, the aforementioned intake angle β1 and the aforementioned exhaust angle β2 are obtuse angles, and the aforementioned outflow angle β 12 and the aforementioned inflow angle β 21 It is an acute angle.

[0079] In this way, by designing the aforementioned inlet angle β1 and outlet angle β2 as obtuse angles, it is more conducive to the inflow and outflow of air, and by designing the aforementioned outlet angle β... 12 and the aforementioned inflow angle β 21 The design features an acute angle, which facilitates the airflow to continue flowing along the grille outlet rib 11b after passing through the grille inlet rib 11a, thereby aiding in the deflection of the airflow.

[0080] The following is for reference Figure 5 The shape of the tandem thrust grid device 1 of the present invention compared with that of conventional thrust reverser devices will be described. Figure 5 This is a comparison diagram of the external appearance of the tandem thrust grid device 1 of the present invention and a conventional thrust reverser device.

[0081] In the existing technology, a large deflection of airflow is forced within the narrow outer space of the engine nacelle by a single thrust reverser grid rib. This can easily lead to boundary layer separation in the flow channel, resulting in flow loss and blockage of the flow channel, thereby reducing the aerodynamic performance of the thrust reverser grid.

[0082] like Figure 5 As shown, compared with the conventional reverse thrust device, the tandem reverse thrust grid device 1 of the present invention divides the original single rib into a grid inlet rib 11a and a grid outlet rib 11b, and changes the reverse thrust airflow deflection originally achieved by a single reverse thrust grid rib to be achieved by two grid ribs, and a slit flow channel is formed between the two grid ribs.

[0083] This can improve the problems that previously, when airflow was deflected by a single grid rib, boundary layer separation occurred in the flow channel, increasing flow losses and reducing the aerodynamic performance of the reverse grid.

[0084] The following is for reference Figure 6A , Figure 6B and Figure 7The advantages of the tandem thrust grid device 1 of the present invention compared with conventional thrust reverser devices will be explained.

[0085] Figure 6A and Figure 6B These are Mach number contour plots of the tandem thrust reverser grid device 1 of the present invention and a conventional thrust reverser device under conventional thrust reverser operating conditions, respectively. Figure 6A and Figure 6B In this diagram, the intensity of the shading is used to represent the speed of the airflow.

[0086] like Figure 6A and Figure 6B As shown, it is clear that previous thrust reversers, which used a single grid rib to force large deflection of airflow, were prone to large-area boundary layer separation.

[0087] In contrast, the tandem push grid device 1 of the present invention has a significant advantage in controlling the boundary layer thickness on the push grid ribs and delaying the airflow diversion in the flow channel because it uses two ribs, grid inlet rib 11a and grid outlet rib 11b, and can effectively suppress boundary layer separation.

[0088] also, Figure 7 The diagram shows a comparison of the flow rate, thrust characteristics, and structural weight of the tandem thrust reverser grid device 1 of the present invention with those of conventional thrust reverser devices at the same engine speed.

[0089] like Figure 7 As shown, compared with conventional thrust reversers, the tandem thrust reverser grid device 1 of the present invention has significant advantages in terms of flow rate, thrust characteristics and structural weight.

[0090] At the same engine speed, the outflow rate of the tandem thrust reverser grid device 1 of the present invention is greater than that of the conventional thrust reverser device, indicating that the tandem thrust reverser grid device 1 of the present invention can improve flow channel blockage and provides a greater margin to avoid the engine from entering a stall state during the thrust reverser opening process.

[0091] Furthermore, at the same engine speed, the tandem thrust reverser grid device 1 of the present invention can achieve greater thrust reverser force, which is beneficial for the engine to achieve the required thrust reverser force at a lower speed. Moreover, the structural weight of the present invention is lower than that of conventional thrust reverser devices, which has a certain weight reduction advantage.

[0092] While the structure and working principle of the present invention have been described above in conjunction with preferred embodiments, those skilled in the art should recognize that the above examples are merely illustrative and do not constitute a limitation of the invention. Modifications and variations can be made to the invention within the spirit and scope of the claims, and all such modifications and variations will fall within the protection scope of the present invention.

[0093] For example, in this invention, an example is shown of the above-mentioned tandem reverse-push grid unit 11 including a grid unit front plate 11c and a grid unit tail plate 11d. However, the invention is not limited to this. It may also exclude the grid unit front plate 11c and the grid unit tail plate 11d, or design the above-mentioned grid unit front plate 11c and the grid unit tail plate 11d as a combination of a grid inlet rib 11a and a grid outlet rib 11b.

[0094] For example, in this invention, an example is shown in which the plurality of grid inlet ribs 11a and the plurality of grid outlet ribs 11b are arranged at equal intervals with grid pitch L. However, this invention is not limited to this. The plurality of grid inlet ribs 11a and the plurality of grid outlet ribs 11b can also be arranged at non-equal intervals according to actual needs, as long as it is suitable for reducing boundary layer separation.

[0095] For example, in this invention, the distance in the flow channel height direction between the outlet end face 11a2 of each of the plurality of grille inlet ribs 11a and the inlet end face 11b1 of each of the plurality of grille outlet ribs 11b is shown as interval d. h The distance along the baseline is the width d. x This is an example, but the present invention is not limited thereto. Depending on actual needs, the outlet end face 11a2 of one of the plurality of grid inlet ribs 11a and the inlet end face 11b1 of one of the plurality of grid outlet ribs 11b may be designed to have different distances, as long as it is suitable for reducing boundary layer separation.

[0096] For example, in this invention, it is shown that there is a gap d between the outlet end face 11a2 of each of the plurality of grille inlet ribs 11a and the inlet end face 11b1 of each of the plurality of grille outlet ribs 11b. h Examples are provided, but the invention is not limited thereto; the interval d between the two in the flow channel height direction is... h It can also be zero, as long as it is suitable for reducing boundary layer separation.

[0097] For example, in this invention, an example is shown of airflow flowing along the grid inlet rib 11a and the grid outlet rib 11b in the tandem reverse-thrust grid unit 11. However, the invention is not limited to this. Multiple grid intermediate ribs may also be provided between the grid inlet rib 11a and the grid outlet rib 11b, as long as they are suitable for deflecting the airflow.

Claims

1. A tandem reverse-push grid device (1), wherein the tandem reverse-push grid device (1) is composed of a plurality of tandem reverse-push grid units (11) arranged along the circumferential direction, characterized in that, Each of the plurality of tandem thrust grid units (11) includes: Multiple grid inlet ribs (11a) are located on the inlet side of the tandem reverse-push grid unit (11); and Multiple grid outlet ribs (11b) are located on the outlet side of the tandem reverse-thrust grid unit (11). The outlet end face (11a2) of the plurality of grid inlet ribs (11a) and the inlet end face (11b1) of the plurality of grid outlet ribs (11b) are spaced apart in the flow channel height direction. ), and in the direction of the baseline, there exists a width ( Separate in a way that allows for spacing, Each of the plurality of tandem reverse-push grid units (11) further includes a grid unit front plate (11c) and a grid unit tail plate (11d), wherein the plurality of grid inlet ribs (11a) and the plurality of grid outlet ribs (11b) are located between the grid unit front plate (11c) and the grid unit tail plate (11d). The outlet end face (11a2) of the plurality of grille inlet ribs (11a) is farther away from the front plate (11c) of the grille unit than the inlet end face (11b1) of the plurality of grille outlet ribs (11b). Gas from the engine enters the tandem thrust reverser grid unit (11) through the grid unit inlet (111), and after passing sequentially through the plurality of grid inlet ribs (11a) and the plurality of grid outlet ribs (11b), flows out of the tandem thrust reverser grid unit (11) through the grid unit outlet (112). After the gas from the engine flows through the front blade profile (11a3) and rear blade profile (11a4) of the grille inlet rib (11a) to the outlet end face (11a2), a small portion of the airflow passes through the width between the grille inlet rib (11a) and the grille outlet rib (11b). The airflow exits through the spaced channels, with most of the airflow flowing out along the front blade profile (11b3) and rear blade profile (11b4) of the grille outlet rib (11b).

2. The tandem reverse-push grid device (1) as described in claim 1, characterized in that, Each of the plurality of tandem push-back grid units (11) further includes a grid unit side plate (11e) that spaces the plurality of tandem push-back grid units (11) apart from each other and is used for mounting the plurality of grid inlet ribs (11a) and the plurality of grid outlet ribs (11b).

3. The tandem reverse-push grid device (1) as described in claim 1 or 2, characterized in that, The plurality of grille inlet ribs (11a), the plurality of grille outlet ribs (11b), the grille unit front plate (11c), and the grille unit tail plate (11d) are formed in an airfoil shape.

4. The tandem reverse-push grid device (1) as described in claim 3, characterized in that, The plurality of grid inlet ribs (11a) and the plurality of grid outlet ribs (11b) are arranged at equal intervals with grid spacing (L) between the front plate (11c) and the rear plate (11d) of the grid unit, respectively.

5. The tandem reverse-push grid device (1) as described in claim 4, characterized in that, The inlet faces of the plurality of grid inlet ribs (11a), the front plate (11c) of the grid unit and the tail plate (11d) of the grid unit are located on the same straight line, and the outlet faces of the plurality of grid outlet ribs (11b), the front plate (11c) of the grid unit and the tail plate (11d) of the grid unit are located on the same straight line.

6. The tandem reverse-push grid device (1) as described in claim 5, characterized in that, The plurality of grille inlet ribs (11a) each have an intake angle relative to the inlet side baseline with their inlet end faces (11a1). The multiple grille outlet ribs (11b) are arranged in a manner such that their outlet end faces (11b2) have an outlet angle relative to the outlet side baseline. Arranged in a manner similar to ).

7. The tandem reverse-push grid device (1) as described in claim 6, characterized in that, The air intake angle ( ) and the exhaust angle ( ( ) is an obtuse angle.

8. The tandem reverse-push grid device (1) as described in claim 7, characterized in that, The angle at the outlet end face (11a2) of the grille inlet rib (11a) is the outflow angle. The grid outlet ribs (11b) are arranged in a manner such that the angle at the inlet end face (11b1) is the inflow angle. Arranged in a manner similar to ).

9. The tandem reverse-push grid device (1) as described in claim 8, characterized in that, The outflow angle ( ) and the inflow angle ( ( ) is an acute angle.

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