Engine nacelle inlet having turbulator segment
A turbulator segment in the engine nacelle inlet transitions laminar to turbulent airflow, addressing overheating issues by enhancing heat transfer and cooling downstream components.
Patent Information
- Application Number
- JP2025077683
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-05-10
- Filing Date
- 2025-05-08
- Publication Date
- 2025-12-09
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.
The introduction of a turbulator segment along the inner flow surface of the nacelle inlet to transition laminar airflow to turbulent airflow, disrupting the boundary layer and enhancing heat transfer through mixing with adjacent cooler airflow.
The turbulent airflow effectively reduces temperatures on downstream structures by promoting heat dissipation and maintaining components within safe operating limits.
Smart Images
Figure 2025179022000001_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 serves 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. One method for heating the inlet is 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 can reach excessively high temperatures. One location of the nacelle inlet that can become excessively high is along the inner flow surface of the nacelle inlet.
[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 extracts heat 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. However, a relatively slow-moving boundary layer 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 includes an inner flow surface, an outer flow surface, and a turbulator segment disposed along the inner flow surface. The turbulator segment extends outward beyond the inner flow surface and is configured to transition laminar airflow along the inner flow surface upstream from the turbulator segment to turbulent airflow downstream from the turbulator segment.
[0006] In another aspect, the agitator segment is a strip connected to the inner flow surface, the strip having an inner surface disposed toward the inner flow surface, an opposing outer surface, a leading edge, and a trailing edge.
[0007]
[0007] In another aspect, the strip extends completely around the nacelle inlet.
[0008]
[0008] In another aspect, the strip comprises a plurality of discrete sections spaced apart by gaps.
[0009]
[0009] In another aspect, the agitator segment includes a plurality of fasteners, the plurality of fasteners including heads extending outwardly beyond the inner flow surface.
[0010]
[0010] In another aspect, the heads are aligned in a row that surrounds the nacelle inlet.
[0011] In another aspect, the agitator segments are disposed on one or more members connected to the inner flow surface.
[0012] In another aspect, one or more members are constructed from a different material than the inner flow surface.
[0013] In another aspect, the agitator segment comprises one or more strips and a fastener extending through the one or more strips to the inner flow surface.
[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 lip skin includes a lip skin inner flow surface extending to an inner lip skin edge. An inner barrel is disposed downstream from the lip skin inner flow surface. A joint is formed between the inner lip skin edge and a leading edge of the inner barrel. A turbulator segment is disposed on the lip skin inner flow surface upstream from the joint. The turbulator segment is configured to transition laminar airflow from the joint to turbulent airflow downstream to extract heat from the inner barrel.
[0015]
[0015] In another aspect, the inner barrel includes inner barrel structural plies constructed from composite materials.
[0016]
[0016] In another aspect, the turbulator segment is a strip connected to the nacelle inlet and extending beyond the lip skin inner flow surface.
[0017]
[0017] In another aspect, the strip is a continuous band that extends completely around the nacelle inlet.
[0018]
[0018] In another aspect, the agitator segment has a leading edge and a trailing edge, the trailing edge being aligned with the joint.
[0019]
[0019] In another aspect, the agitator segment has a leading edge and a trailing edge, and the agitator segment is positioned forward of the joint, whereby the trailing edge is spaced a certain distance from the inner lip skin edge.
[0020]
[0020] In another aspect, the partition has a flange that spans the lip skin annulus and extends across the inside of the joint.
[0021]
[0021] In another aspect, the agitator segment includes a plurality of fastener heads that extend outwardly beyond the inner flow surface.
[0022]
[0022] In another aspect, the lip skin inner flow surface is substantially smooth.
[0023] In another aspect, the agitator segment is a trough in the lip skin inner flow surface.
[0024] 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 in a laminar flow along an upstream section of the inner flow surface, directing the air over a raised turbulator segment on the inner flow surface after the air passes over the upstream section to transition the air to turbulent flow, and directing the air in a turbulent flow over a downstream section of the inner flow surface of the nacelle inlet.
[0025]
[0025] In another aspect, the method further includes directing the air over a strip attached to the inner flow surface to transition the laminar flow to turbulent flow.
[0026]
[0026] 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]
[0027] [Figure 1]
[0027] FIG. 1 is an isometric view of an aircraft having a nacelle located under each of the main wings. [Figure 2]
[0028] FIG. 2 is a perspective view of a nacelle inlet. [Figure 3]
[0029] 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]
[0030] FIG. 4 is an enlarged view of the nacelle inlet of FIG. [Figure 5]
[0031] FIG. 10 is a schematic cross-sectional view of a strip attached to the lip skin and forming the agitator segment upstream from the inner barrel edge band. [Figure 6]
[0032] FIG. 1 is a side schematic view of a strip forming an agitator segment. [Figure 7]
[0033] FIG. 1 is a schematic cross-sectional view of a stirrer segment disposed on the inner flow surface of a nacelle inlet. [Figure 8]
[0034] FIG. 10 is a schematic cross-sectional view of a fastener attached to the lip skin forming the agitator segment upstream from the inner barrel edge band. [Figure 9]
[0035] FIG. 1 is a schematic cross-sectional view of a stirrer segment disposed on the inner flow surface of a nacelle inlet. [Figure 10]
[0036] FIG. 10 is a schematic cross-sectional view of an enlarged section of a lip skin forming the agitator segment upstream from the inner barrel edge band. [Figure 11]
[0037] FIG. 10 is a schematic cross-sectional view of a valley in the lip skin that forms a turbulator upstream from the inner barrel edge band. [Figure 12]
[0038] 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
[0028]
[0039] 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.
[0029]
[0040] The engine 103 includes a nacelle 20 that extends around the exterior. The nacelle 20 has an aerodynamic profile, such as round or elliptical, to reduce drag. The nacelle 20 includes a nacelle inlet 21. The nacelle inlet 21 directs airflow into the engine 103, and a centerline C / L extends through the nacelle inlet 21. 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 inlet 21, 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.
[0030]
[0041] 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.
[0031]
[0042] The inner barrel 30 extends aft 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 extending between a leading 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 leading edge 31 of the inner barrel 30 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 30 may include various structures and configurations different from those shown herein.
[0032]
[0043] 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 the joint 91. 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.
[0033]
[0044] 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.
[0034]
[0045] 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 in the range of 350°F to 500°F. The temperature of the inner barrel edge band 34 increases due to communication 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.
[0035]
[0046] The airflow across the inner flow surface 61 removes heat from the inner barrel edge band 34 and the lip skin 22. 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 its temperature. To address the heat removal issue, the turbulator segment 50 on 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 disrupt the boundary layer heat transfer effects from one or more components. The turbulent airflow is effective at drawing heat from one or more components and reducing temperatures compared to laminar airflow due to boundary layer mixing. In one embodiment, the turbulent airflow reduces the temperature of the inner edge band 34.
[0036]
[0047] In some embodiments, the turbulator segment 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 an existing aircraft.
[0037]
[0048] The agitator segment 50 can include a variety of different configurations. The agitator segment 50 can be positioned at various distances relative to the inner lip skin edge 24. In some embodiments, the agitator segment 50 is positioned a distance d from the inner lip skin edge 24. In other embodiments, the agitator segment 50 is positioned at the inner lip skin edge 24.
[0038]
[0049] As shown in FIG. 5 , in one embodiment, the disrupter segment 50 is a strip 70 attached to the lip skin inner flow surface 23. The strip 70 includes an inner surface 74 that contacts the lip skin inner flow surface 23 and an opposite, exposed 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 thickness is sized to extend outward beyond the surface of the lip skin inner flow surface 23. The thickness may be constant throughout the strip 70, as shown in FIG. 5 , or may vary along one or more sections.
[0039]
[0050] One or more of the leading edge 72 and the trailing edge 73 may be configured to promote turbulent airflow. As shown in FIG. 6, 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. In some embodiments, as shown in FIG. 6, the angles α and β are acute. In some embodiments, as shown in FIG. 5, the angles α and β are substantially 90 degrees. The angles α and β may be the same as shown in FIGS. 5 and 6, or may be different. In some embodiments, one or both of the leading edge 72 and the trailing edge 73 are flat. In other embodiments, one or both include a variable surface, such as, but not limited to, one or more curvatures and / or rounding. The strip 70 has a width W measured between the leading edge 72 and the trailing edge 73. The width W may be constant or may vary along the nacelle inlet 21.
[0040]
[0051] The strip 70 can be positioned at various locations along the lip skin inner flow surface 23. As shown in FIG. 5 , in some embodiments, the strip 70 is aligned at the joint 91. The trailing edge 73 of the strip 70 is aligned with the inner lip skin edge 24. In other embodiments, the strip 70 is positioned at various intervals forward of the inner lip skin edge 24.
[0041]
[0052] In some embodiments, the strip 70 is a continuous band that extends completely around the nacelle inlet 21. In other embodiments, the strip 70 is formed by one or more discrete sections 76. FIG. 7 shows an embodiment having the strip 70 formed by sections 76a, 76b, and 76c. The sections 76 are spaced apart by gaps. In some embodiments, the sections 76 are disposed completely around the nacelle inlet 21. In other embodiments, the sections 76 are disposed along one or more discrete sections of the nacelle inlet 21. The sections 76 may have the same or different shapes, sizes, and configurations.
[0042]
[0053] In some embodiments, one or more sections 76 are formed by a fastener 77 that extends outwardly beyond the lip skin inner flow surface 23. Figure 8 shows an embodiment having a fastener 77 connected to the lip skin 22. The fastener 77 includes a head 78 that is disposed outwardly beyond the lip skin inner flow surface 23. The fastener 77 also includes a body 79 that extends into and / or through one or more of the lip skin 22 and the flange 41. In some embodiments, several fasteners 77 are aligned in a row that extends around a portion or the entire circumference of the nacelle inlet 21.
[0043]
[0054] In some embodiments, the turbulator segment 50 includes a single strip 70. In other embodiments, the turbulator segment 50 includes two or more strips 70. FIG. 9 illustrates an embodiment having a pair of strips 70a, 70b, each connected to the lip skin 22. As shown in FIG. 9, in one embodiment, each of 70a, 70b is continuous around the nacelle inlet 21. In other embodiments, the strips 70a, 70b have different shapes, sizes, and / or configurations. FIG. 9 illustrates an embodiment of the turbulator segment 50 having a pair of strips 70a, 70b. Other embodiments include three or more separate strips 70.
[0044]
[0055] The one or more strips 70 and sections 76 may be constructed from a variety of different materials, including, but not limited to, aluminum, composites, and plastics. The strips 70 are connected to the nacelle inlet 21 in a variety of ways, such as, but not limited to, with one or more mechanical fasteners or adhesives.
[0045]
[0056] FIG. 10 illustrates an embodiment in which the turbulator segment 50 is formed by an enlarged section 80 of the lip skin 22. In some embodiments, the enlarged section 80 has a greater thickness than the remainder of the lip skin 22. This thickness results in the enlarged section 80 extending outward a greater distance than the remainder of the lip skin inner flow surface 23 and the edge band 34. The enlarged section 80 extends around a limited section or the entire nacelle inlet 21. As shown in FIG. 10 , in some embodiments, the enlarged section 80 is located at the inner lip skin edge 24. In other embodiments, the enlarged section 80 is spaced forward from the inner lip skin edge 24.
[0046]
[0057] In some embodiments described above, the disrupter segment 50 includes one or more members extending outward from the lip skin inner flow surface 23 to provide turbulent airflow. In other embodiments, the disrupter segment 50 includes one or more valleys 81 in the lip skin 22. FIG. 11 shows an embodiment with a valley 81 formed in the lip skin 22. The valley 81 has a width measured between a leading edge 82 and a trailing edge 83. The depth of the valley 81 below the lip skin inner flow surface 23 can vary. In one embodiment, each of the leading edge 82 and the trailing edge 83 is flat. In some embodiments, one or both of the leading edge 82 and the trailing edge 83 have a curved, angled, or other non-flat shape.
[0047]
[0058] In some embodiments, the turbulator segment 50 includes a single design feature (e.g., only one or more strips 70, only one or more sections 76, or only one or more valleys 81). In other embodiments, the turbulator segment 50 includes two or more different design features. For example, the turbulator segment 50 includes a combination of strips 70, and / or sections 76, and / or valleys 81. In one embodiment, the turbulator segment 50 includes a first design feature (e.g., strips 70) along a first section of the nacelle inlet 21 and a second design feature (e.g., sections 76) along a second section of the nacelle inlet 21.
[0048]
[0059] The turbulator segments 50 create a discontinuous surface along the lip skin inner flow surface 23. The turbulator segments 50 are positioned along the lip skin inner flow surface 23 to direct turbulent airflow into 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, inner barrel edge band 34, inner barrel perforated skin 36, inner barrel structural ply 32, and 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 inner barrel edge band 34 results in cooling of the bulkhead flange 41. In some embodiments, the lip skin inner flow surface 23 upstream and downstream from the turbulator segment 50 is substantially smooth.
[0049]
[0060] 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 structural ply 32, including 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 composed of 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 can be composed of a variety of materials, 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 segment 50 encourages the airflow to cool the inner barrel edge band 34 below these limits.
[0050]
[0061] 12 shows a flowchart of a method for cooling a section of the inner flow surface 61 of the nacelle inlet 21. The method includes directing air through the nacelle inlet 21. The air initially has laminar flow along an upstream section of the inner flow surface 61 (block 200). After passing through the upstream section, the air is directed over raised turbulator segments 50 on the inner flow surface 61, where the air transitions to turbulent flow (block 202). The turbulent air is directed over a downstream section of the inner flow surface 61 of the nacelle inlet 21 (block 204).
[0051]
[0062] 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 vehicles, such as land craft, watercraft, and spacecraft, as well as power plant applications.
[0052]
[0063] The term "substantially" in connection with a quantity or measurement means that the recited characteristic, parameter, or value need not be achieved exactly. Rather, deviations or variations (including, for example, tolerances, measurement errors, measurement accuracy limits, and other factors known to those skilled in the art) may occur to the extent that they do not eliminate the effect intended to be produced by the feature.
[0053]
[0064] 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 agitator segments (50) disposed along the inner flow surface (61); the turbulator segment (50) extends outward beyond the inner flow surface (61) and is configured to transition laminar airflow along the inner flow surface (61) upstream from the turbulator segment (50) to turbulent airflow downstream from the turbulator segment (50).
2. 2. The nacelle inlet of claim 1, wherein the turbulator segment is a strip connected to the inner flow surface, the strip having an inner surface disposed toward the inner flow surface, an opposite outer surface, a leading edge, and a trailing edge.
3. The nacelle inlet of claim 2 , wherein the strip (70) extends completely around the nacelle inlet.
4. The nacelle inlet of claim 2 , wherein the strip (70) comprises a plurality of discrete sections (76) spaced apart by gaps.
5. 2. The nacelle inlet of claim 1, wherein the agitator segment includes a plurality of fasteners, the plurality of fasteners including heads that extend outwardly beyond the inner flow surface.
6. The nacelle inlet of claim 5 , wherein the heads (78) are aligned in a row circumferentially around the nacelle inlet.
7. The nacelle inlet of claim 1 , wherein the turbulator segments (50) are formed on one or more members constructed from a different material than the inner flow surface (61).
8. The agitator segment (50) comprises: one or more strips (70), and The nacelle inlet of claim 1, comprising a fastener (77) extending through the one or more strips (70) to the inner flow surface (61).
9. 1. A nacelle inlet for an engine, comprising: a lip skin (22) disposed at a forward end of the nacelle inlet, the lip skin (22) having a lip skin inner flow surface (23) extending to an inner lip skin edge (24); an inner barrel (30) disposed downstream from the lip skin inner flow surface (23); a joint (91) formed between the inner lip skin edge (24) and the front edge (31) of the inner barrel (30); and a turbulator segment (50) disposed on the lip skin inner flow surface (23) upstream from the joint (91), the turbulator segment (50) configured to transition laminar airflow to turbulent airflow downstream from the joint to extract heat from the inner barrel (30).
10. The nacelle inlet of claim 9 , wherein the inner barrel (30) comprises an inner barrel structural ply (32) constructed from a composite material.
11. 10. The nacelle inlet of claim 9, wherein the turbulator segment is a strip connected to the nacelle inlet, the strip extending beyond the lip skin inner flow surface.
12. The nacelle inlet of claim 11, wherein the strip (70) is a continuous band that extends completely around the nacelle inlet.
13. The nacelle inlet of claim 9, wherein the turbulator segment (50) comprises a leading edge and a trailing edge, the trailing edge being aligned with the joint (91).
14. 10. The nacelle inlet of claim 9, wherein the turbulator segment (50) has a leading edge and a trailing edge, the turbulator segment (50) being disposed forward of the joint, and the trailing edge being spaced a distance from the inner lip skin edge (24).
15. 10. The nacelle inlet of claim 9, 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).
16. 10. The nacelle inlet of claim 9, wherein the turbulator segment (50) comprises a plurality of fastener heads (77), the plurality of fastener heads (77) extending outwardly beyond the lip skin inner flow surface (23).
17. The nacelle inlet of claim 9, wherein the lip skin inner flow surface (23) is substantially smooth.
18. The nacelle inlet of claim 9, wherein the turbulator segment (50) is a valley (81) in the lip skin inner flow surface (23).
19. 1. A method of cooling a section of an inner flow surface of a nacelle inlet, comprising: directing air through the nacelle inlet (21) in a laminar flow along an upstream section of the inner flow surface (61); directing the air over raised agitator segments (50) on the inner flow surface (61) after the air has passed over the upstream section to transition the air to turbulence; and inducing the air in a turbulent flow over a downstream section of the inner flow surface (61) of the nacelle inlet (21).
20. 20. The method of claim 19, further comprising directing the air over a strip (70) attached to the inner flow surface (61) to transition the laminar flow to turbulent flow.