Engine nacelle air inlet with turbulator section

Abstract

An engine nacelle air inlet having a turbulator section. A nacelle air inlet for an engine. The nacelle air inlet includes an inner flow surface, an outer flow surface, and a turbulator section positioned along the inner flow surface. The turbulator section extends outwardly beyond the inner flow surface and is configured to convert laminar airflow along the inner flow surface upstream of the turbulator section into turbulent airflow downstream of the turbulator section.

Description

Technical Field

[0001] This disclosure generally relates to the field of engine nacelles, and more specifically, to the field of changing airflow from laminar to turbulent within engine nacelle air inlets to promote cooling. Background Technology

[0002] The engine nacelle is the outer shell of an aircraft that extends around the engine. The nacelle includes air intakes that direct air to the engine. The function of the nacelle air intakes is to protect the engine (such as a gas turbine engine) from the intake of foreign objects. The nacelle air intakes are also configured to direct air to the engine. During aircraft operation, the nacelle air intakes are heated to prevent icing. One method for heating the air intakes occurs by directing heated air from the engine to one or more internal sections of the nacelle air intake. One problem with heating is that one or more sections of the nacelle air intake may reach excessively high temperatures. One area where the nacelle air intake may experience high temperatures is along the internal flow surfaces of the nacelle air intake.

[0003] Cooling of one or more sections of the nacelle air intake occurs due to heat transfer to the air entering the engine through the intake. As a product of airflow along the surface, heat is drawn from one or more sections, thus reducing the surface temperature. The internal flow surfaces of the nacelle air intake are configured to promote laminar airflow over one or more sections. However, the boundary layer moves relatively slowly and retains the heat drawn from the heated lip skin, carrying this heat downstream. Turbulent airflow disrupts this boundary layer heat transfer effect by promoting mixing with adjacent cooler airflow, thereby reducing heat transfer to downstream adjacent structures.

[0004] Therefore, it is necessary to locally change the airflow from laminar to turbulent within the cabin air intake in order to reduce the excessively high temperature of adjacent structures downstream of the heating section. Summary of the Invention

[0005] One aspect relates to a nacelle air inlet for an engine. The nacelle air inlet includes an internal flow surface, an external flow surface, and a turbulence section positioned along the internal flow surface. The turbulence section extends outward beyond the internal flow surface and is configured to transform laminar airflow upstream of the turbulence section along the internal flow surface into turbulent airflow downstream of the turbulence section.

[0006] In another aspect, the turbulence section is a strip connected to the internal flow surface, which includes an inner surface positioned toward the internal flow surface, an opposite outer surface, a leading edge, and a trailing edge.

[0007] On the other hand, the strip extends completely around the circumference of the cabin air intake.

[0008] In another respect, the strip comprises multiple discrete segments separated by gaps.

[0009] In another aspect, the turbulence section includes multiple fasteners, which include heads that extend outward beyond the internal flow surface.

[0010] On the other hand, the heads are arranged in a row around the circumference of the cabin air intake.

[0011] In another aspect, the turbulence section is positioned on one or more components that are connected to the internal flow surface.

[0012] In another respect, the one or more components are constructed of a material different from the internal flow surface.

[0013] In another aspect, the turbulence section includes one or more strips and fasteners that extend through the one or more strips and into the internal flow surface.

[0014] One aspect relates to a nacelle air inlet for an engine. The nacelle air inlet includes a lip skin positioned at the front end of the nacelle air inlet, the lip skin including an internal flow surface extending to the inner edge of the lip skin. An inner cylinder is positioned downstream of the internal flow surface of the lip skin. A joint is formed between the inner edge of the lip skin and the leading edge of the inner cylinder. A turbulence section is positioned upstream of the joint at the internal flow surface of the lip skin, the turbulence section being configured to transform laminar airflow into turbulent airflow downstream of the joint to draw heat from the inner cylinder.

[0015] In another aspect, the inner cylinder includes an inner cylinder structural layer constructed of composite materials.

[0016] On the other hand, the turbulence section is a strip that is connected to the nacelle air intake and extends outward beyond the internal flow surface of the lip skin.

[0017] On the other hand, a strip is a continuous band that extends circumferentially around the cabin air intake.

[0018] In another aspect, the turbulence section includes a leading edge and a trailing edge, with the trailing edge aligned with the junction.

[0019] In another aspect, the turbulence section includes a leading edge and a trailing edge, and the turbulence section is positioned in front of the joint such that the trailing edge is spaced a certain distance from the inner edge of the lip skin.

[0020] In another aspect, the bulkhead extends across the lip skin ring and includes a flange that extends across the inside of the joint.

[0021] In another aspect, the turbulence section includes multiple fastener heads that extend outward beyond the internal flow surface.

[0022] On the other hand, the internal flow surface of the lip skin is basically smooth.

[0023] In another aspect, the turbulence section is a groove in the flow surface inside the lip skin.

[0024] One aspect relates to a method for cooling a section of the internal flow surface of a naval air inlet. The method includes: guiding air in laminar flow along an upstream section of the internal flow surface through the naval air inlet; after the air has passed through the upstream section, guiding the air over a raised turbulence section on the internal flow surface and converting the air into turbulence; and guiding the air in turbulence over a downstream section of the internal flow surface of the naval air inlet.

[0025] In another aspect, the method also includes guiding air across strips attached to the internal flow surface and transforming laminar flow into turbulent flow.

[0026] In the embodiment of the nacelle air intake, the turbulence section (50) is a strip (70) that is connected to the nacelle air intake and extends outward beyond the internal flow surface (23) of the lip skin.

[0027] In the embodiment of the cabin air intake, the strip (70) is a continuous strip that extends circumferentially around the cabin air intake.

[0028] In an embodiment of the nacelle air intake, the turbulence section (50) includes a leading edge and a trailing edge, and the trailing edge is aligned with the joint (91).

[0029] In an embodiment of the cabin air intake, the turbulence section (50) includes a leading edge and a trailing edge, wherein the turbulence section (50) is positioned in front of the joint, and the trailing edge is spaced apart from the inner edge (24) of the lip skin by a certain distance.

[0030] In an embodiment of the cabin air intake, a bulkhead (40) extending across the lip skin ring (47) is also included, the bulkhead (40) including a flange (41) extending across the inside of the joint (91).

[0031] In an embodiment of the nacelle air intake, the turbulence section (50) includes a plurality of fastener heads (77) extending outward beyond the internal flow surface (23) of the lip skin.

[0032] In the embodiment of the cabin air intake, the internal flow surface (23) of the lip skin is substantially smooth.

[0033] In the embodiment of the cabin air intake, the turbulence section (50) is a groove (81) in the flow surface (23) inside the lip skin.

[0034] A method for cooling a section of the internal flow surface of a cabin air inlet, the method comprising: guiding air in a laminar flow along an upstream section of the internal flow surface (61) through the cabin air inlet (21); after the air has passed through the upstream section, guiding the air over a raised turbulence section (50) on the internal flow surface (61) and converting the air into turbulence; and guiding the air in a turbulent flow over a downstream section of the internal flow surface (61) of the cabin air inlet (21).

[0035] In an implementation of the method, the air is also guided across strips (70) attached to the internal flow surface (61) and the laminar flow is converted into turbulent flow.

[0036] The features, functions, and advantages already discussed can be implemented independently in each aspect or in combination in other aspects, and further details can be seen in the following description and figures. Attached Figure Description

[0037] Figure 1 It is an isometric view of the aircraft with the cabin positioned below each wing.

[0038] Figure 2 This is a perspective view of the cabin air intake.

[0039] Figure 3 It is a schematic cross-sectional view of a portion of the engine compartment having an internal flow surface leading to the engine and an opposite external flow surface.

[0040] Figure 4 yes Figure 3 Enlarged view of the air intake section in the middle cabin.

[0041] Figure 5 It is a schematic cross-sectional view of the strips attached to the lip skin and forming the turbulence section upstream of the inner cylinder edge.

[0042] Figure 6 This is a side view schematic diagram of the strips that form the turbulence section.

[0043] Figure 7 It is a schematic cross-sectional view of the turbulence section located on the internal flow surface of the air intake in the nacelle.

[0044] Figure 8 It is a schematic cross-sectional view of the fasteners attached to the lip skin and forming the turbulence section upstream of the inner cylinder edge band.

[0045] Figure 9 It is a schematic cross-sectional view of the turbulence section located on the internal flow surface of the air intake in the nacelle.

[0046] Figure 10This is a schematic cross-sectional view of the enlarged section of the lip skin that forms the turbulence section upstream of the inner cylinder edge zone.

[0047] Figure 11 This is a schematic cross-sectional view of the groove in the lip skin, which forms a turbulence section upstream of the inner cylinder edge zone.

[0048] Figure 12 This is a flowchart of a method for cooling a section of the internal flow surface of the air intake in the engine compartment. Detailed Implementation

[0049] Figure 1 An aircraft 100 configured to transport personnel and / or cargo is shown. The aircraft 100 typically includes a fuselage 101 and wings 102. Engines 103 are mounted on the wings 102 to propel the aircraft 100 during flight. The number and orientation of the engines 103 can vary depending on the aircraft 100. In some examples, the engines 103 are gas turbine engines, such as turbofan engines.

[0050] Engine 103 includes a nacelle 20 extending around its exterior. Nacelle 20 has an aerodynamic profile (e.g., circular or elliptical) to reduce drag. Nacelle 20 includes a nacelle air intake 21 that directs airflow into engine 103 and has a centerline C / L extending through the nacelle air intake 21. Figure 2 and Figure 3 As shown, the cabin air inlet 21 includes a front end 60, an internal flow surface 61 extending along the air inlet 21, and an external flow surface 62 extending along the outer side. The internal flow surface 61 and the external flow surface 62 may be formed by one or more different components.

[0051] The forward section of the cabin air intake 21, including the front end 60, is formed by a lip skin 22. The lip skin 22 forms part of both an inner flow surface 61 and an outer flow surface 62. Specifically, the lip skin 22 includes an inner flow surface 23 extending between the inner edge 24 and the hilite 25. The lip skin 22 also includes an outer flow surface 26 extending from the hilite 25 to the outer edge 27 of the lip skin.

[0052] The inner cylinder 30 extends rearward from the inner edge 24 of the lip skin. The inner cylinder 30 includes an inner cylinder structural layer 32, a composite core 33, and an inner cylinder perforated skin 36. The inner cylinder structural layer 32 includes an inner cylinder edge band 34 extending between a leading edge 31 and an inner cylinder ramp transition 35. The inner cylinder edge band 34 forms part of an internal flow surface 61. The leading edge 31 of the inner cylinder 30 forms a junction 91 with the inner edge 24 of the lip skin. The composite core 33 is bonded to the inner cylinder structural layer 32 rearward from the inner cylinder ramp transition 35. The inner cylinder 30 may include various other constructions and configurations besides those shown herein.

[0053] A generally annular forward bulkhead 40 extends radially across the lip skin ring 47. In some examples, the forward bulkhead 40 includes a flange 41 extending across the joint 91. In other examples, the flange 41 is a separate component from the forward bulkhead 40. A duct 45 is formed between the bulkhead 40 and the lip skin 22 at the forward section of the cabin air inlet 21. Furthermore, a generally annular aft bulkhead (not shown) extends radially between the inner cylinder 30 and the outer cylinder 28.

[0054] The nacelle air intake 21 is configured to direct airflow to the engine 103. The airflow entering through the nacelle air intake 21 flows in the direction of arrow A along the internal flow surface 61 formed by the inner flow surface 23 of the lip skin, the inner cylinder edge band 34 and the inner cylinder perforated skin 36.

[0055] The internal flow surface 23 of the lip skin is heated to prevent surface icing. In some examples, the heat is provided by high-temperature bleed air drawn from the engine 103 and directed into a duct 45 formed in the forward section of the nacelle air intake 21. In some examples, the temperature of the bleed air is approximately 1000℉. The heated air directed into this area can cause one or more components in the nacelle air intake 21 to be heated to high temperatures. In some examples, the forward bulkhead 40 is heated to a temperature of approximately 740℉, and the flange 41 is heated to a temperature in the range of 350℉-500℉. Furthermore, the temperature of the inner cylinder edge band 34 rises due to conduction with the flange 41. In some examples, the temperature of the inner cylinder edge band 34 may approach the range of approximately 350℉-500℉.

[0056] Airflow across the internal flow surface 61 removes heat from the inner cylinder edge zone 34 and the lip skin 22. The surface of the lip skin 22 is substantially smooth, resulting in laminar airflow across the internal flow surface 61. Heat transfer occurs between the lip skin 22 and the laminar airflow, increasing the temperature of the airflow boundary layer along the internal flow surface 61. This heat is transferred downstream to the inner cylinder edge zone 34, thereby increasing its temperature. To address the heat dissipation problem, a turbulence section 50 at the inner flow surface 23 of the lip skin converts the laminar airflow into turbulent airflow. The turbulent airflow is directed across one or more sections of the downstream internal flow surface 61 to disrupt the boundary layer heat transfer effect from the one or more components. The turbulent airflow draws heat from the one or more components and is more effective than the laminar airflow in reducing temperature due to boundary layer mixing. In one example, the turbulent airflow reduces the temperature of the inner cylinder edge zone 34.

[0057] In some examples, the turbulence section 50 is formed on the nacelle air intake 21 during manufacturing. In other examples, the process is performed on an existing aircraft in service. The process utilizes tools and machinery to facilitate the retrofitting of existing aircraft.

[0058] The turbulence section 50 can include various different configurations. The turbulence section 50 can be positioned at various distances relative to the inner edge 24 of the lip skin. In some examples, the turbulence section 50 is spaced apart from the inner edge 24 of the lip skin by a distance d. In other examples, the turbulence section 50 is positioned at the inner edge 24 of the lip skin.

[0059] exist Figure 5 In one example shown, the turbulence segment 50 is a strip 70 attached to the inner flow surface 23 of the lip skin. The strip 70 includes an inner surface 74 that contacts the inner flow surface 23 of the lip skin and an exposed, opposite outer surface 75. The strip 70 also includes a leading edge 72 and a trailing edge 73. The strip 70 includes a thickness measured between the inner surface 74 and the outer surface 75, the dimension of which is designed to extend outward beyond the surface of the inner flow surface 23 of the lip skin. Figure 5 As shown, the thickness of the entire strip 70 can be constant, or the thickness can vary along one or more segments.

[0060] One or more of the leading edge 72 and trailing edge 73 can be configured to promote turbulent airflow. For example... Figure 6 As shown, the leading edge 72 is aligned with the inner surface 74 at an angle α, and the trailing edge 73 is aligned with the inner surface 75 at an angle β. Figure 6 In some of the examples shown, angles α and β are acute angles. Figure 5 In some of the examples shown, angles α and β are essentially 90°. Angles α and β can be... Figure 5 and Figure 6The details shown may be the same or different. In some examples, one or both of the leading edge 72 and the trailing edge 73 are flat. In other examples, one or both include variable surfaces, examples including, but not limited to, one or more curves and / or rounded surfaces. The strip 70 includes a width W measured between the leading edge 72 and the trailing edge 73. The width W along the nacelle air intake 21 may be constant or may vary.

[0061] The strip 70 can be positioned in various directions along the internal flow surface 23 of the lip skin. In such cases... Figure 5 In some of the examples shown, the strip 70 is aligned at the joint 91, with the trailing edge 73 of the strip 70 aligned with the inner edge 24 of the lip skin. In other examples, the strip 70 is positioned at various intervals in front of the inner edge 24 of the lip skin.

[0062] In some examples, strip 70 is a continuous strip extending completely around the nacelle air intake 21. In other examples, strip 70 is formed by one or more discrete segments 76. Figure 7 An example of a strip 70 formed by segments 76a, 76b, and 76c is shown. Segments 76 are separated by gaps. In some examples, segments 76 are positioned completely around the circumference of the nacelle air intake 21. In other examples, segments 76 are positioned along one or more separate segments of the nacelle air intake 21. Segments 76 may have the same or different shapes, sizes, and configurations.

[0063] In some examples, one or more segments 76 are formed by fasteners 77 extending outward beyond the internal flow surface 23 of the lip skin. Figure 8 An example of fastener 77 being attached to lip skin 22 is shown. Fastener 77 includes a head 78 positioned outward beyond the internal flow surface 23 of the lip skin. Fastener 77 also includes a body 79 extending to and / or passing through one or more of the lip skin 22 and flange 41. In some examples, multiple fasteners 77 are arranged in a row, extending around a circumferential portion or the entire circumference of the cabin air intake 21.

[0064] In some examples, the turbulence section 50 comprises a single strip 70. In other examples, the turbulence section 50 comprises two or more strips 70. Figure 9 An example is shown where a pair of strips 70a and 70b are respectively connected to the lip skin 22. In such a way... Figure 9 In one example shown, each strip 70a, 70b is continuous around the circumference of the cabin air intake 21. In other examples, strips 70a, 70b include different shapes, sizes, and / or constructions. Figure 9 This is an example of a turbulence section 50 with a pair of strips 70a and 70b. Other examples include more than three separate strips 70.

[0065] One or more strips 70 and segments 76 may be constructed from a variety of different materials, including but not limited to aluminum, composite materials, and plastics. Strips 70 are connected to the nacelle air intake 21 in various ways, such as, but not limited to, one or more of mechanical fasteners and adhesives.

[0066] Figure 10 An example is shown in which the turbulence section 50 is formed by an enlarged section 80 of the lip skin 22. In some examples, the thickness of the enlarged section 80 is greater than the rest of the lip skin 22. This thickness causes the enlarged section 80 to extend outward a greater distance than the rest of the internal flow surface 23 and edge band 34 of the lip skin. The enlarged section 80 may extend around a limited section of the nacelle inlet 21 or the entire circumference. Figure 10 In some of the examples shown, the enlarged section 80 is positioned at the inner edge 24 of the lip skin. In other examples, the enlarged section 80 is spaced forward from the inner edge 24 of the lip skin.

[0067] In some of the examples disclosed above, the turbulence section 50 includes one or more components extending outward from the inner flow surface 23 of the lip skin to induce turbulent airflow. In other examples, the turbulence section 50 includes one or more slots 81 in the lip skin 22. Figure 11 An example of a groove 81 formed in the lip skin 22 is shown. The groove 81 has a width measured between a leading edge 82 and a trailing edge 83. The depth of the groove 81 below the internal flow surface 23 of the lip skin can vary. In one example, each of the leading edge 82 and the trailing edge 83 is flat. In other examples, one or both of the leading edge 82 and the trailing edge 83 include curves, angles, or other non-flat shapes.

[0068] In some examples, turbulence section 50 includes a single design feature (e.g., only one or more stripes 70, only one or more sections 76, only one or more slots 81). In other examples, turbulence section 50 includes two or more different design features. For example, turbulence section 50 includes a combination of stripes 70 and / or sections 76 and / or slots 81. In one example, turbulence section 50 includes a first design feature (e.g., stripe 70) along a first section of nacelle inlet 21 and a second design feature (e.g., section 76) along a second section of nacelle inlet 21.

[0069] The turbulence section 50 creates surface discontinuities along the inner flow surface 23 of the lip skin. The turbulence section 50 is positioned along the inner flow surface 23 of the lip skin to introduce turbulent airflow into one or more downstream sections of the inner flow surface 61. This turbulent airflow promotes cooling of one or more downstream sections of the nacelle inlet 21, including the lip skin 22, inner cylinder edge band 34, inner cylinder perforated skin 36, inner cylinder structural layer 32, and composite core 33. This cooling occurs due to the mixing of the boundary layer with the cooler adjacent airflow, a result of the transition from laminar to turbulent flow. Cooling may also occur through conduction in one or more components. In one example, cooling of one or both of the inner flow surface 23 of the lip skin and the inner cylinder edge band 34 results in cooling of the bulkhead flange 41. In some examples, the inner flow surface 23 of the lip skin upstream and downstream of the turbulence section 50 is substantially smooth.

[0070] In one example, one or more components of the internal flow surface 61 are constructed of a composite layer material. In a specific example, structural layer 32, including the inner cylinder edge band 34, is constructed of a composite layer material. The composite layer material comprises one or more layers of fibers impregnated with one or more thermosetting and thermoplastic matrix resins. The fibers can be composed of a variety of materials, including but not limited to aromatic polyamides, polyolefins, metals, glass, carbon, boron, ceramics, minerals, and combinations thereof. The fibers are impregnated with a thermosetting or thermoplastic matrix resin. In another example, the matrix resin comprises a mixture of both thermosetting and thermoplastic resins. The matrix resin can be composed of a variety of substances, including but not limited to acrylic acid, fluorocarbons, polyamides (PA), polyethylene (PE) (such as polyethylene terephthalate (PET)), polyesters, polypropylene (PP), polycarbonate (PC), polyurethane (PU), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), and other material compositions. This construction from the composite material specifies the maximum operating limit (MOL) temperature and the maximum short-time limit temperature. The turbulent airflow generated by the turbulent section 50 promotes airflow cooling of the inner cylinder edge zone 34, keeping it below these limits.

[0071] Figure 12 A method is illustrated for cooling a section of the internal flow surface 61 of the nacelle air inlet 21. The method includes guiding air through the nacelle air inlet 21, wherein the air initially has laminar flow along an upstream section of the internal flow surface 61 (box 200). After the air has passed through the upstream section, the air is guided across a raised turbulence maneuver section 50 on the internal flow surface 61 and converted to turbulence (box 202). The air is then guided in turbulence across a downstream section of the internal flow surface 61 of the nacelle air inlet 21 (box 204).

[0072] In the example disclosed above, the cabin 20 houses the engine 103 and is used in an aircraft. However, it should be understood that this disclosure is equally applicable to cabins 20 for other types of engines in other applications (e.g., but not limited to, other vehicles, such as, but not limited to, land vehicles, ships and spacecraft, and power plant applications).

[0073] Regarding quantities or measurements, the term "substantially" means that the characteristic, parameter, or value does not need to be precisely achieved. Instead, deviations or variations (including, for example, tolerances, measurement errors, measurement accuracy limitations, and other factors known to those skilled in the art) may occur in quantities that do not exclude the effects that the characteristic is intended to provide.

[0074] Of course, the invention may be practiced in ways other than those specifically set forth herein without departing from its essential characteristics. This embodiment should be considered illustrative rather than restrictive in all respects, and all variations within the meaning and equivalence of the appended claims are intended to be included therein.

Claims

1. A nacelle air intake for an engine, the nacelle air intake comprising: Internal flow surface (61); External flow surface (62); Turbulence section (50), which is positioned along the internal flow surface (61); and The turbulence section (50) extends outward beyond the internal flow surface (61) and is configured to transform laminar airflow upstream of the turbulence section (50) along the internal flow surface (61) into turbulent airflow downstream of the turbulence section (50).

2. The cabin air intake according to claim 1, wherein the turbulence section (50) is a strip (70) connected to the internal flow surface (61), the strip (70) comprising an inner surface (74) positioned toward the internal flow surface (61), an opposite outer surface (75), a leading edge (72) and a trailing edge (73).

3. The nacelle air intake according to claim 2, wherein the strip (70) extends completely around the circumference of the nacelle air intake.

4. The cabin air intake according to claim 2, wherein the strip (70) comprises a plurality of discrete segments (76) separated by gaps.

5. The nacelle air intake according to claim 1, wherein the turbulence section (50) includes a plurality of fasteners (77), the plurality of fasteners (77) including a head (78) extending outward beyond the internal flow surface (61).

6. The cabin air intake according to claim 5, wherein the heads (78) are arranged in a row around the circumference of the cabin air intake.

7. The cabin air intake according to claim 1, wherein the turbulence section (50) is formed on one or more components constructed of a material different from the internal flow surface (61).

8. The nacelle air inlet according to claim 1, wherein the turbulence section (50) comprises: One or more stripes (70); and Fastener (77) extends through the one or more strips (70) and into the internal flow surface (61).

9. A nacelle air intake for an engine, the nacelle air intake comprising: A lip skin (22) positioned at the front end of the cabin air inlet, the lip skin (22) including an internal flow surface (23) of the lip skin extending to the inner edge (24) of the lip skin. The inner cylinder (30) is located downstream of the internal flow surface (23) of the lip skin; A joint (91) is formed between the inner edge (24) of the lip skin and the leading edge (31) of the inner cylinder (30); and A turbulence section (50), located upstream of the joint (91) at the internal flow surface (23) of the lip skin, is configured to transform laminar airflow into turbulent airflow downstream of the joint to draw heat from the inner cylinder (30).

10. The cabin air intake according to claim 9, wherein the inner cylinder (30) comprises an inner cylinder structural layer (32) constructed of composite material.

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