Engine nacelle inlet with rough agitator surface
The introduction of a turbulator surface with a roughened agitator in engine nacelle inlets transitions laminar to turbulent airflow, addressing overheating issues by enhancing heat transfer and cooling efficiency.
Patent Information
- Application Number
- JP2025077684
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-05-10
- Filing Date
- 2025-05-08
- Publication Date
- 2025-12-16
AI Technical Summary
Existing engine nacelle inlets experience excessively high temperatures due to laminar airflow, which retains heat and transfers it downstream, leading to overheating of adjacent structures.
A turbulator surface with a roughened agitator surface is introduced to transition laminar airflow to turbulent airflow, enhancing heat transfer and cooling efficiency by promoting boundary layer mixing.
The turbulent airflow effectively reduces temperatures on downstream components by improving heat transfer, preventing overheating and maintaining component integrity.
Smart Images
Figure 2025183158000001_ABST
Abstract
Description
[Technical Field]
[0001]
[0001] The present disclosure relates generally to the field of engine nacelles, and more particularly to the field of transitioning airflow from laminar to turbulent within engine nacelle inlets to enhance cooling. [Background technology]
[0002]
[0002] An engine nacelle is a housing that extends around an aircraft engine. The nacelle includes an inlet that directs air into the engine. The nacelle inlet may serve to protect the engine, such as a gas turbine engine, from ingesting foreign objects. The nacelle inlet is further configured to direct air into the engine. The nacelle inlet is heated to prevent icing during use of the aircraft. Heating is achieved by directing heated air from the engine into one or more interior sections of the nacelle inlet. A problem with heating is that one or more sections of the nacelle inlet may reach excessively high temperatures. One location of the nacelle inlet that may become excessively high is along the inner flow surface of the nacelle inlet.
[0003]
[0003] Cooling of one or more sections of the nacelle inlet occurs as a result of heat transfer to the air entering the engine through the nacelle inlet. The action of air flowing over the surface results in heat being extracted from the one or more sections, reducing the surface temperature. The inner flow surface of the nacelle inlet is configured to promote laminar airflow across the one or more sections. Laminar airflow is uniform and reduces resistance. However, the boundary layer, which is relatively slow to mix, retains the heat extracted from the heated lip skin and carries this heat downstream. Turbulent airflow disrupts the heat transfer effect of this boundary layer by promoting mixing with adjacent cooler airflow, thereby reducing heat transfer to adjacent downstream structures.
[0004]
[0004] It is therefore necessary to locally transition the airflow from laminar to turbulent within the nacelle inlet in order to reduce excessively high temperatures on adjacent structures downstream of the heated section. Summary of the Invention
[0005]
[0005] One aspect is directed to a nacelle inlet for an engine, the nacelle inlet including an inner flow surface, an outer flow surface, and a turbulator surface disposed along the inner flow surface, the turbulator surface including a roughened surface configured to transition laminar airflow along the inner flow surface upstream from the turbulator surface to turbulent airflow downstream from the turbulator surface.
[0006]
[0006] In another aspect, the agitator surface extends continuously around the inner flow surface of the nacelle inlet.
[0007]
[0007] In another aspect, the agitator surface comprises a plurality of sections spaced around the inner flow surface of the nacelle inlet, with gaps disposed between the sections.
[0008]
[0008] In another aspect, the agitator surface is a strip having a leading edge and a trailing edge, the strip having a width measured between the leading edge and the trailing edge.
[0009]
[0009] In another aspect, the width is constant along the agitator surface.
[0010] In another aspect, the strip has a chevron shape.
[0011] In another aspect, the strip is a first strip and the agitator surface further comprises one or more additional strips, each strip having a roughened surface.
[0012] In another aspect, the agitator surface comprises a peened surface having a plurality of depressions.
[0013]
[0013] In another aspect, an agitator surface is positioned along the inner flow surface between the highlight and the downstream edge of the lip skin.
[0014]
[0014] One aspect is directed to a nacelle inlet for an engine. The nacelle inlet includes a lip skin disposed at a forward end of the nacelle inlet, the nacelle inlet including a lip skin inner flow surface. An inner barrel is disposed downstream from the lip skin inner flow surface. A turbulator surface is disposed within the lip skin inner flow surface, the turbulator surface configured to transition laminar airflow to turbulent airflow downstream along the inner barrel to extract heat from the inner barrel.
[0015]
[0015] In another aspect, the lip skin inner flow surface comprises a smooth surface and the agitator surface comprises a rough surface.
[0016] In another aspect, the agitator surface comprises a peened surface having a plurality of depressions.
[0017]
[0017] In another aspect, a joint is formed between the downstream edge of the lip skin inner flow surface and the upstream edge of the inner barrel, and the agitator surface is positioned forward from the joint.
[0018]
[0018] In another aspect, the partition has a flange that spans the lip skin annulus and extends across the inside of the joint.
[0019]
[0019] In another aspect, the agitator surface extends continuously around the nacelle inlet.
[0020]
[0020] In another aspect, the agitator surface is arranged in a strip having a leading edge and a trailing edge.
[0021] In another aspect, the strip is a first strip and the agitator surface further comprises one or more additional strips spaced apart from the first strip.
[0022] One aspect is directed to a method of cooling a section of an inner flow surface of a nacelle inlet, the method including directing air through the nacelle inlet, the air initially having laminar flow along an upstream section of the inner flow surface, directing the air over a stirrer surface on the inner flow surface after the air has passed through the upstream section to transition the air to having turbulent flow, and directing the air with turbulent flow over a downstream section of the inner flow surface of the nacelle inlet.
[0023]
[0023] In another aspect, the method further includes inducing turbulent airflow through an inner barrel of the nacelle inlet positioned downstream from a lip skin of the nacelle inlet.
[0024]
[0024] In another aspect, directing air over the agitator surface includes directing air over depressions formed on the inner flow surface.
[0025]
[0025] The above-described features, functions, and advantages can be realized alone in various aspects or can be combined in further multiple aspects, details of which can be confirmed by referring to the following description and accompanying drawings. [Brief explanation of the drawings]
[0026] [Figure 1]
[0026] FIG. 1 is an isometric view of an aircraft having a nacelle located under each of the main wings. [Figure 2]
[0027] FIG. 2 is a perspective view of a nacelle inlet. [Figure 3]
[0028] 1 is a schematic cross-sectional view of a portion of a nacelle having an inner flow surface leading to an engine and an opposing outer flow surface. [Figure 4]
[0029] FIG. 4 is an enlarged view of the nacelle inlet of FIG. [Figure 5]
[0030] FIG. 1 is a schematic cross-sectional view of a stirrer surface disposed on the inner flow surface of a nacelle inlet. [Figure 6]
[0031] FIG. 10 is a schematic cross-sectional view of another agitator surface disposed on the inner flow surface of the nacelle inlet. [Figure 7]
[0032] FIG. 10 is a schematic cross-sectional view of another agitator surface disposed on the inner flow surface of the nacelle inlet. [Figure 8]
[0033] FIG. 10 is a schematic cross-sectional view of another agitator surface disposed on the inner flow surface of the nacelle inlet. [Figure 9]
[0034] 1 is a flowchart of a method for cooling a section of an inner flow surface of a nacelle inlet. DETAILED DESCRIPTION OF THE INVENTION
[0027]
[0035] 1 illustrates an aircraft 100 configured to transport people and / or cargo. Aircraft 100 generally includes a fuselage 101 and wings 102. Engines 103 are attached to wings 102 for propelling aircraft 100 during flight. The number and location of engines 103 may vary depending on aircraft 100. In some embodiments, engines 103 are gas turbine engines, such as turbofan engines.
[0028]
[0036] The engine 103 includes a nacelle 20 that extends around the exterior. The nacelle 20 has an aerodynamic profile to reduce drag. The nacelle 20 includes a nacelle inlet 21. The nacelle inlet 21 directs airflow into the engine 103 and extends around a centerline C / L. As shown in FIGS. 2 and 3 , the nacelle inlet 21 includes a forward end 60, an inner flow surface 61 that extends along the interior side, and an outer flow surface 62 that extends along the exterior side. The inner flow surface 61 and the outer flow surface 62 may be formed by one or more different components.
[0029]
[0037] The forward section of the nacelle inlet 21, including the forward end 60, is formed by a lip skin 22. The lip skin 22 forms portions of both an inner flow surface 61 and an outer flow surface 62. Specifically, the lip skin 22 includes a lip skin inner flow surface 23 that extends between an inner lip skin edge 24 and a highlight 25. The lip skin 22 further includes a lip skin outer flow surface 26 that extends from the highlight 25 to an outer lip skin edge 27.
[0030]
[0038] The inner barrel 30 extends rearward from the inner lip skin edge 24. The inner barrel 30 includes an inner barrel structural ply 32, a composite core 33, and an inner barrel perforated skin 36. The inner barrel structural ply 32 includes an inner barrel edge band 34 that extends between the inner barrel edge 31 and an inner barrel ramp transition 35. The inner barrel edge band 34 forms a portion of the inner flow surface 61. The inner barrel edge 31 forms a joint 91 with the inner lip skin edge 24. The composite core 33 is joined to the inner barrel structural ply 32 aft of the inner barrel ramp transition 35. The inner barrel perforated skin 36 forms a portion of the inner flow surface 61.
[0031]
[0039] A generally annular forward bulkhead 40 extends radially across the lip skin annulus 47. In some embodiments, the forward bulkhead 40 includes a flange 41 that extends across a joint 91 formed by the inner lip skin edge 24 and the inner barrel edge 31. In other embodiments, the flange 41 is a separate member from the forward bulkhead 40. A duct 45 is formed between the bulkhead 40 and the lip skin 22 in the forward section of the nacelle inlet 21. In addition, a generally annular aft bulkhead (not shown) extends radially between the inner barrel 30 and the outer barrel 28.
[0032]
[0040] The nacelle inlet 21 is configured to direct airflow to the engine 103. Airflow entering through the nacelle inlet 21 flows in the direction of arrow A along an inner flow surface 61 formed by the lip skin inner flow surface 23, the inner barrel edge band 34, and the inner barrel perforated skin 36.
[0033]
[0041] The lip skin inner flow surface 23 is heated to prevent ice from forming on the surface. In some embodiments, heat is provided from hot bleed air routed from the engine 103 and directed into a duct 45 formed in the forward section of the nacelle inlet 21. In some embodiments, the bleed air has a temperature of approximately 1000°F. The heated air directed to this area may cause one or more of the components within the nacelle inlet 21 to heat to high temperatures. In some embodiments, the forward bulkhead 40 is heated to a temperature of approximately 740°F, and the flange 41 is heated to a temperature range of 350°F to 650°F. Additionally, the temperature of the inner barrel edge band 34 increases due to conduction with the flange 41. In some embodiments, the temperature of the inner barrel edge band 34 may approach a range of approximately 350°F to 500°F.
[0034]
[0042] The airflow across the inner flow surface 61 removes heat from the inner barrel edge band 34 and the lip skin 22. However, the surface of the lip skin 22 is substantially smooth, resulting in laminar airflow across the inner 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 inner flow surface 61. This heat is carried downstream to the inner barrel edge band 34, increasing the temperature of the inner barrel edge band 34. The turbulator surface 50 formed within the lip skin inner flow surface 23 transitions the laminar airflow to turbulent airflow. The turbulent airflow is induced across one or more sections of the downstream inner flow surface 61 to improve the effectiveness of boundary layer heat transfer from one or more components. In one embodiment, the turbulent airflow reduces the temperature of the inner edge band 34.
[0035]
[0043] The agitator surface 50 comprises a roughened surface formed on the lip skin inner flow surface 23. The turbulent airflow is more effective at drawing heat away from one or more components, such as the inner barrel edge band 34, and reducing temperatures more than laminar airflow due to boundary layer mixing.
[0036]
[0044] The agitator surface 50 can include various types of rough surfaces that transition the airflow from laminar to turbulent. In some embodiments, the rough surface 50 includes a peened surface. The peened surface includes indentations 53 in the surface of the lip skin 22. The indentations 53 can have different shapes and / or sizes to direct turbulence downstream from the surface 50. The peened surface can be formed by various processes. In one embodiment, the agitator surface 50 can be formed by a roto-peening process. This process uses a tool having a mandrel with flaps that feature applicable sized shot. The tool is operated at a predetermined rotational speed and is applied onto the surface of the lip skin inner flow surface 23 for a specified length of time. In another embodiment, the process includes media blasting or shot peening to modify the surface.
[0037]
[0045] In some embodiments, the turbulator surface 50 is formed on the nacelle inlet 21 during manufacturing. In other embodiments, the process is performed on an existing aircraft in use. The process utilizes tools and machinery that facilitate retrofitting to existing aircraft.
[0038]
[0046] 5 shows one embodiment of agitator surface 50 on lip skin inner flow surface 23. Agitator surface 50 is forward of inner lip skin edge 24 by a distance D. Distance D can vary because agitator surface 50 can be at various locations between highlight 25 and inner lip skin edge 24. As shown in FIG. 4, in some embodiments, agitator surface 50 is located along lip skin inner flow surface 23 upstream from joint 91. In some embodiments, agitator surface 50 is located at inner lip skin edge 24.
[0039]
[0047] The agitator surface 50 includes a leading edge 51 and a trailing edge 52. In some embodiments, one or both of the edges 51, 52 are well-defined due to a particular forming process. The edges 51, 52 may include a variety of shapes, such as straight, curved, and angular features (see FIG. 8 ). The agitator surface 50 has a width W measured between the edges 51, 52. The width W may be constant or may vary along the agitator surface 50.
[0040]
[0048] In another aspect, the turbulator surface 50 extends completely around the nacelle inlet 21. FIG. 5 illustrates an embodiment in which the turbulator surface 50 is continuously circumferential. In other embodiments, the turbulator surface 50 extends around one or more limited sections around the inner flow surface 61. FIG. 6 illustrates an embodiment in which the turbulator surface 50 has multiple sections 54a, 54b, 54c. Each of the sections 54 includes a roughened surface configured to direct turbulent airflow. Gaps 55 are formed between one or more of the sections 54. The various sections 54 and gaps 55 may have the same or different shapes, sizes, and / or configurations.
[0041]
[0049] In some embodiments, the agitator surface 50 includes a single strip 56, as shown in Figure 5. In other embodiments, the agitator surface 50 includes two or more strips 56. Figure 7 shows an embodiment having a pair of strips 56a, 56b aligned parallel to one another. Figure 8 shows an embodiment having a pair of strips 56a, 56b, each having a chevron configuration.
[0042]
[0050] The agitator surface 50 includes a roughened surface that is rougher than the surface of the lip skin inner flow surface 23. As shown in FIG. 5 , in one embodiment, the lip skin inner flow surface 23 upstream and downstream of the agitator surface 50 is smoother than the agitator surface 50.
[0043]
[0051] The turbulator surface 50 is positioned along the lip skin inner flow surface 23 to direct turbulent airflow to one or more downstream sections of the inner flow surface 61. The turbulent airflow promotes cooling of one or more downstream sections of the nacelle inlet 21, including the lip skin 22, the inner barrel edge band 34, the inner barrel perforated skin 36, the inner barrel structural ply 32, and the composite core 33. This cooling occurs due to the boundary layer mixing with cooler adjacent airflow as a result of the transition from laminar to turbulent flow. Cooling may also occur to one or more of the components via conduction. In one embodiment, cooling of one or both of the lip skin inner flow surface 23 and the inner barrel edge band 34 results in cooling of the bulkhead flange 41.
[0044]
[0052] In one embodiment, one or more of the components of the inner flow surface 61 are constructed from a composite ply material. In one specific embodiment, the inner barrel edge band 34 is constructed from a composite ply material. The composite ply includes one or more layers of fibers impregnated with one or more thermoset and thermoplastic matrix resins. The fibers may be constructed from a variety of materials, including, but not limited to, aramid, polyolefin, metal, glass, carbon, boron, ceramic, mineral, and combinations thereof. The fibers are impregnated with a thermoset or thermoplastic matrix resin. In another embodiment, the matrix resin includes a hybrid system of both thermoset and thermoplastic resins. The matrix resin may be constructed from a variety of substances, including, but not limited to, acrylic, fluorocarbon, polyamide (PA), polyethylene (PE) such as polyethylene terephthalate (PET), polyester, polypropylene (PP), polycarbonate (PC), polyurethane (PU), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), and other material compositions. This construction from composite materials defines a maximum operating limit (MOL) temperature and a maximum short-term limit temperature. The turbulent airflow directed by the agitator surface 50 encourages the airflow to cool the inner barrel edge band 34 below these limits.
[0045]
[0053] 9 illustrates a method for cooling a section of the inner flow surface 61 of the nacelle inlet 21. The method includes inducing air through the nacelle inlet 21. The airflow is initially in a laminar state along a section upstream from the turbulator surface 50 of the inner flow surface 61 (block 200). After passing through the upstream section, the air is induced over the turbulator surface 50 of the inner flow surface 61, transitioning the laminar airflow to turbulent airflow (block 202). The turbulent airflow is induced over a downstream section of the inner flow surface 61 of the nacelle inlet 21 (block 204).
[0046]
[0054] In the embodiments disclosed above, the nacelle 20 houses the engine 103 and is used onboard an aircraft. However, it should be understood that the present disclosure applies equally to nacelles 20 for other types of engines in other applications, such as, but not limited to, other vehicle or power plant applications.
[0047]
[0055] The present invention may, of course, be practiced otherwise than as specifically set forth herein without departing from the essential characteristics thereof. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced within their scope.
Claims
1. 1. A nacelle inlet for an engine, comprising: an inner flow surface (61); an outer flow surface (62); and a nacelle inlet comprising a stirrer surface (50) disposed along the inner flow surface (61), the stirrer surface (50) having a roughened surface and configured to transition laminar airflow along the inner flow surface (61) upstream from the stirrer surface (50) to turbulent airflow downstream from the stirrer surface (50).
2. The nacelle inlet of claim 1, wherein the agitator surface (50) extends continuously around the inner flow surface (61) of the nacelle inlet (21).
3. 2. The nacelle inlet of claim 1, wherein the agitator surface (50) comprises a plurality of sections (54) spaced circumferentially about an inner flow surface (61) of the nacelle inlet (21), the plurality of sections (54) having gaps (55) disposed between the plurality of sections (54).
4. 2. The nacelle inlet of claim 1, wherein the agitator surface is a strip having a leading edge and a trailing edge, the strip having a width measured between the leading edge and the trailing edge.
5. The nacelle inlet of claim 4, wherein the width is constant along the agitator surface (50).
6. The nacelle inlet of claim 4, wherein the strip (56) has a chevron shape.
7. The nacelle inlet of claim 4, wherein the strip (56) is a first strip and the turbulator surface (50) further comprises one or more additional strips, each strip having a roughened surface.
8. The nacelle inlet of claim 1 , wherein the agitator surface (50) comprises a peened surface having a plurality of dimples (53).
9. 2. The nacelle inlet of claim 1, wherein the agitator surface (50) is disposed along the inner flow surface (61) between a highlight (25) and a downstream edge (24) of a lip skin (22).
10. 1. A nacelle inlet for an engine, comprising: a lip skin (22) disposed at a forward end (60) of the nacelle inlet, the nacelle inlet having a lip skin inner flow surface (23); an inner barrel (30) disposed downstream from the lip skin inner flow surface (23); and a nacelle inlet comprising: a turbulator surface (50) disposed within the lip skin inner flow surface (23), the turbulator surface (50) configured to transition laminar airflow to turbulent airflow downstream along the inner barrel (30) to extract heat from the inner barrel (30).
11. The nacelle inlet of claim 10, wherein the lip skin inner flow surface (23) comprises a smooth surface and the turbulator surface (50) comprises a rough surface.
12. The nacelle inlet of claim 11, wherein the agitator surface (50) comprises a peened surface having a plurality of dimples (53).
13. 11. The nacelle inlet of claim 10, further comprising a joint (91) formed between a downstream edge (24) of the lip skin inner flow surface (23) and an upstream edge (31) of the inner barrel (30), the agitator surface (50) being disposed forward from the joint (91).
14. 14. The nacelle inlet of claim 13, further comprising a bulkhead (40) spanning the lip skin annulus (47), the bulkhead (40) comprising a flange (41) extending across the inside of the joint (91).
15. The nacelle inlet of claim 10, wherein the agitator surface (50) extends continuously around the nacelle inlet (21).
16. The nacelle inlet of claim 10, wherein the agitator surface (50) is arranged in a strip (56) having a leading edge (51) and a trailing edge (52).
17. 17. The nacelle inlet of claim 16, wherein the strip is a first strip, and the agitator surface further comprises one or more additional strips spaced apart from the first strip.
18. A method of cooling a section of an inner flow surface (61) of a nacelle inlet (21), comprising: directing air through the nacelle inlet (21), the air initially having a laminar airflow along an upstream section of the inner flow surface (61); directing the air over an agitator surface (50) on the inner flow surface (61) after the air has passed through the upstream section to transition the air into a turbulent airflow; and inducing the air having turbulent airflow over a downstream section of the inner flow surface (61) of the nacelle inlet (21).
19. 20. The method of claim 18, further comprising: directing the turbulent airflow through an inner barrel (30) of the nacelle inlet (21) located downstream from a lip skin (22) of the nacelle inlet (21).
20. 20. The method of claim 18, wherein directing the air over the agitator surface (50) includes directing the air over depressions (53) formed on the inner flow surface (61).