Patent Application
20170058828
Referring to
Each of the cascade vanes 104 includes a leading edge and a trailing edge, such as for example leading edge 114a and trailing edges 114b and 114c. As the nomenclature implies, a leading edge is the portion of a cascade vane 104 that initially interfaces to the bypass flow/air 108, whereas a trailing edge is the portion of the cascade vane 104 that interfaces to the external environment and is the last portion of the cascade vane 104 to interface to the (redirected) bypass air 108.
Conventional design practice has dictated that the cascade vanes 104 have a constant thickness/dimension over the length/span of the cascade 104, in progressing from the leading edge to the trailing edge. Such practice may facilitate ease in manufacture and assembly of the cascade 104. For example, cascades have typically been fabricated using carbon fiber, where sheets of material of a same/common dimension are layered. However, a price is paid in using such design practices in terms of performance/efficiency of the thrust reverser system 100. For example, the reverse thrust that is produced is sub-optimal for a thrust reverser system 100 of a given size/footprint.
The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below.
Aspects of the disclosure are directed to a system associated with a thrust reverser of an aircraft, comprising: a plurality of cascade vanes configured in accordance with a substantially arc-tangent profile, where a leading edge of a first of the cascade vanes has a first width, and a trailing edge of the first of the cascade vanes has a second width that is different from the first width. In some embodiments, the second width is less than the first width. In some embodiments, the second width is approximately 0.5 times the width of the first width. In some embodiments, the leading edge is associated with an arc-portion of the arc-tangent profile, and the trailing edge is associated with a tangent-portion of the arc-tangent profile. In some embodiments, a second leading edge of a second of the cascade vanes has a third width, and a second trailing edge of the second of the cascade vanes has a fourth width. In some embodiments, the second of the cascade vanes is located aft of the first of the cascade vanes. In some embodiments, the fourth width is different from the second width. In some embodiments, the system further comprises a blocker door configured to redirect a portion of a bypass flow towards the cascade vanes when the thrust reverser is deployed. In some embodiments, the second width is different from the first width in an amount greater than a first threshold such that a rearward acting force imposed on the thrust reverser structure is greater than a second threshold. In some embodiments, the second width is different from the first width in an amount greater than a first threshold, and the first threshold is based on an amount of deviation in an exiting air flow angle that can be tolerated before an impact on at least one of engine efflux re-ingestion or aircraft impingement performance is realized in an amount greater than a second threshold.
The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements.
It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities.
Referring to
The system 200 may include one or more cascades/cascade vanes 204. The cascade vanes 204 may adhere to one or more shapes/profiles, such as for example a substantially arc-tangent profile. The portion of the cascade vanes 204 below (superimposed) reference line 224 may adhere to the arc-portion of the arc-tangent profile. The portion of the cascade vanes 204 above the reference line 224 may adhere to the tangent-portion of the arc-tangent profile.
Each of the cascade vanes 204 may include a leading edge and a trailing edge, such as for example leading edges 214a and 214d, and trailing edges 214b and 214c. The leading edges may be associated with the arc-portion of the arc-tangent profile. The trailing edges may be associated with the tangent-portion of the art-tangent profile.
The edges 214a-214d may have associated widths/dimensions. For example, a first of the edges (e.g., leading edge 214a) may have a first width/thickness and a second of the edges (e.g., trailing edge 214b) may have a second width. In this example, the second width may be the same as, or different from, the first width. The second width may be less than (e.g., approximately 0.5 times the width of) the first width. In some embodiments, the first and second widths may be specified in terms of one or more thresholds. As the second width is decreased relative to the first width, the exit flow area of the cascade 204 increases. As the air flow rate is increased, the amount of rearward force acting on the thrust reverser structure is increased. The increased effective flow area and the increased rearward force together improve the reverse thrust performance. However, as the second width is decreased relative to the first width, the deviation in the flow angle of the exiting air flow increases relative to a configuration having a constant vane thickness throughout the chord (e.g., the system 100 of
In some embodiments, a width associated with a first trailing edge (e.g., trailing edge 214b) may be the same as, or different from, a width associated with a second trailing edge (e.g., trailing edge 214c).
Referring now to
In view of the examples described above, aspects of the disclosure may provide for a modification (e.g., a reduction) in terms of thicknesses associated with a trailing edge of a cascade vane. Such a modification may result in a change in the effective flow exit area of the thrust reverser cascade array and thereby the rearward acting force on the thrust reverser structure. In this manner, the performance/efficiency of a thrust reverser system may be increased/maximized for a thrust reverser system of a given size/footprint.
The modification of the trailing edge thicknesses may change (e.g., increase) an exit area associated with the cascades/cascade vanes. This change in exit area may result in a change (e.g., an increase) in terms of cascade mass flow. The vector of the exiting cascade flow may remain largely unchanged, despite the modification to the trailing edge thicknesses, such that the engine re-ingestion and stability/control aspects might not be appreciably impacted. Aspects of the disclosure may be used to modify (e.g., increase) the effective flow area of the cascade/cascade vanes.
Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.
