Patent Application
20150108247
The present disclosure relates to an aircraft nacelle, and more particularly, to acoustic properties, sound waves and air flow associated with aircraft nacelle structures.
Typical aircraft turbofan jet engines include a fan that draws and directs a flow of air into a nacelle and, subsequently, into and around an engine core. The nacelle surrounds the engine core and helps promote the flow of air into the fan and turbine engine that drives the fan. Bypass flow is air that is directed around the engine core. In modern turbofan engines, the bypass flow typically provides the majority of thrust for an aircraft. The bypass flow also can be used to help slow a landed aircraft. Thrust reversers mounted in the nacelle structure selectively reverse the direction of the bypass flow to generate reverse thrust. During normal engine operation, the bypass flow may or may not be mixed with the turbine engine core exhaust before exiting the engine assembly. Typical engines of jet aircraft generally produce high levels of audible noise during normal operation. As such, reducing noise in particular locations may be desirable.
According to various embodiments, a “U” shaped inverted track beam flange for coupling aspects of a thrust reverser is described. The geometry of the inverted track beam flange increases the total noise cancellation capabilities of a nacelle structure comprising the inverted track beam flange. The inverted track beam flange may be coupled to an inner fixed structure of a cascade/blocker door type of thrust reverser. The inner fixed structure (IFS) of said thrust reverser may be coupled to the inverted track beam flange along an attachment flange. An inverted track beam flange may include a track beam face and a track beam flange side wall. Noise cancellation structures formed in the IFS may be directly adjacent to a side wall of the inverted track beam flange. The disclosure also includes a nacelle structure comprising an inner fixed structure coupled to an inverted track beam flange. The inner fixed structure may be coupled to the inverted track beam flange along an attachment flange.
The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements.
The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this invention and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. The scope of the invention is defined by the appended claims. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact.
As used herein, “aft” refers to the direction associated with the tail (e.g., the back end) of an aircraft, or generally, to the direction of exhaust of the gas turbine. As used herein, “forward” refers to the direction associated with the nose (e.g., the front end) of an aircraft, or generally, to the direction of flight or motion.
As described above, and with reference to
With reference to
Conventional systems may employ a plurality of drag links, each coupled, at a first end, to a plurality of blocker doors and, at a second end, to an inner fixed structure 105 (“IFS”). The IFS 105 defines the interior aerodynamic surface of the annular bypass air duct, and surrounds the engine core forming a substantially annular enclosed space between it and the engine core. The IFS 105 is situated about an engine core inboard of the translating sleeve. Thus, the space between the IFS 105 and the translating sleeve defines an air duct through which bypass air flows to generate thrust.
During a thrust reversing operation, the translating sleeve may be urged aft by a series of translating sleeve actuators (“TRAs”). As the translating sleeve translates aft, the cascade array may be exposed. Likewise, as the translating sleeve is translated aft, the first end of each drag link (coupled to the translating sleeve) may translate aft. As this occurs, the drag links employed by conventional systems may drag or pull each blocker door radially inward to block airflow. Airflow reflects from each blocker door through the cascade array, generating reverse thrust.
The translating sleeve may be made in two units, each of generally C-shape in front (and rear) elevation, which are supported for sliding on upper and lower track beams 165, 170 that extend rearwardly from the bulkhead. Upon command, generally initiated by the pilot, the actuators drive the translating sleeve rearwardly. The inner wall member of the translating sleeve moves to a location that places its inner, forward edge close to the cowl of the gas turbine, a position in which bypass airflow to the rear of the air duct is blocked. The outer wall member moves with the inner wall member away from the fan case cowling, thus forming an opening rearwardly of the bulkhead between the bypass air duct and the exterior of the engine. The bypass airflow flows out through the opening. A cascade array, which is composed of several sections having frames that support curved vanes, turns the air flow so that it flows outwardly and forwardly.
As described above, jet engine nacelles typically include thrust reversing structures, or simply thrust reversers 60. Thrust reversers 60 often include a structure known as a cascade as well as a structure known as a translating sleeve. The cascade comprises a plurality of vents that redirect airflow during certain operations (e.g., landing) to generate reverse thrust. The translating sleeve comprises a tapering generally cylindrical structure. The translating sleeve may be disposed about the cascade in a stowed position. The translating sleeve may translate from a forward position to a more aft position during deployment (i.e., engagement of the thrust reverser) to expose the cascade. Thus, during flight, a cascade may be stowed or enclosed within a translating sleeve to prevent reverse thrust. During landing, however, the translating sleeve may translate aft to expose the cascade. Translating sleeve may move along tracks 165, 170.
According to various embodiments and with reference to
Cells 250 may be configured to cancel and/or suppress sound waves of various wavelengths. The length of a cell 250 may extend along the y axis. The length of each cell 250 may be configured in accordance with the sound wave 225 length that is desired to be canceled and/or suppressed. Stated another way, the dimensions of each noise suppressing structures 200, such as cell 250 may be dependent on the noise frequencies and attenuation desired. The amount of acoustic treatment in the fan duct is increased which may provide more noise attenuation and reduced “neighborhood noise.”
With reference to
Referring again to
Track beam 120 may comprise a face 140. Upper track 165 and lower track 170 may be located along face 140. Tracks 165, 170 may be flush with face 140. Tracks 165, 170 may extend from the surface of face 140 (as shown in
As shown, the noise suppressing panel 200 may be integral to the IFS 105 surfaces. Stated another way, the composite materials integral to IFS 105 may comprise core 250. Track beam 120 may be coupled, such as through fasteners (e.g. rivets 110) to IFS 105. For example, an “L” shaped attachment flange 115 may extend along a surface of IFS 105 for attaching track beam 120 to IFS 105. Side wall 130 may be substantially perpendicular to attachment flange 115. A “Z” shape may be formed from the interface of attachment flange 115, side wall 130, and face 140. IFS 105 may comprise a fire seal 180 coupled to a surface, such as a non-airflow surface. Fasteners 110 may be inserted in and/or coupled to IFS 105 according to high/exacting tolerances, such as requiring a substantially flush mount to the IFS 105 to better provide for smoother air flow. Note, in the system of
According to various embodiments and with reference to
Relocating attachment flange 315 to an inverted position may expand noise suppressing systems 200 surface area on/in IFS 105. For instance, location 325 which was previously occupied by attachment flange 115 on prior art (as shown in
Attachment flange 315 may be hidden behind side wall 330 as viewed from the perspective of bypass airflow. In this way, the airflow of the system may be increased as compare with the system of
According to various embodiments, there is no gap between a surface of IFS 105 and side wall 330. Stated another way, side wall 330 and IFS 105 surface are adjacent. With brief reference to FIG. attachment flange 115 lies between surface of IFS 105 and side wall 130. Though side wall 330 is depicted as an approximately 90 angle from the surface of IFS 105, other angles and shapes of relief are contemplated herein.
Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “various embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.
Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the inventions. The scope of the inventions is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials.
