Patent Application
20180363588
Contemporary turbo-prop engine aircraft can include one or more propellers attached to engines of the aircraft. Exhaust gases generated within the engines can be directed outward via an exhaust assembly. The direction in which exhaust gases exit the exhaust assembly can provide additional thrust to that provided by the propellers.
Exhaust gases can make an almost 180 degree turn in direction when exiting the exhaust assembly. The turn can include a low radius before discharged to ambient air. Separation within the exhaust gases can reduce overall exhaust system and engine performance. Minimizing the separation is beneficial for improved performance.
In one aspect, the present disclosure relates to an exhaust assembly for a turbine engine comprising an exhaust conduit with the exhaust conduit comprising a reverse flow portion defining a turn with an interior, and at least one vortex generator provided within the interior of the turn.
The reverse flow portion can comprise an exhaust stub extending from an exhaust collector to an exhaust outlet defining the exhaust conduit and forming the turn. The exhaust collector can comprise an inner radius and an outer radius greater than the inner radius at the turn, and the vortex generator is located on the inner radius. The inner radius can be less than the outer radius.
The vortex generator can be secured to or integral with the exhaust collector. The at least one vortex generator can be multiple vortex generators stacked along the inner radius.
The exhaust collector can further comprise an anti-ice scoop. The anti-ice scoop can be fluidly coupled to an anti-ice system via a snorkel. The exhaust collector can comprise an inner radius and an outer radius greater than the inner radius at the turn, and the anti-ice scoop can be located on the inner radius. The anti-ice scoop can be the vortex generator.
In another aspect, the present disclosure relates to a turbine engine having a turbine section, a compressor section, and a combustor, the turbine engine comprising an exhaust assembly coupled to the turbine section and having a reverse flow portion defining a turn, and at least one vortex generator provided at the turn.
The reverse flow portion can comprise an exhaust stub extending from an exhaust collector to an exhaust outlet defining an exhaust conduit and forming the turn. The exhaust collector can comprise an inner radius and an outer radius greater than the inner radius at the turn, and the vortex generator is located on the inner radius. The vortex generator can be secured to or integral with the exhaust collector. The at least one vortex generator can be multiple vortex generators stacked along the inner radius.
The exhaust collector can further comprise an anti-ice scoop. The anti-ice scoop can be fluidly coupled to an anti-ice system via a snorkel. The anti-ice scoop can be the vortex generator.
In another aspect, the present disclosure relates to a method of exhausting combustion gas from a turbine engine, the method comprising reversing a flow of combustion gas exiting a turbine of the engine, and generating a vortex in the flow of combustion gas during the reversing.
The reversing can comprise flowing the combustion gas through a turn in an exhaust conduit. The generating a vortex can comprise flowing the combustion gas over a vortex generator located within the turn. The method can further include scooping a portion of the combustion gas into an anti-ice scoop and circulating the combustion gas around an inlet.
In the drawings:
The described embodiments of the present disclosure are directed to an exhaust assembly for a turbine engine. For purposes of illustration, the present disclosure will be described with respect to a turboprop engine for an aircraft. It will be understood, however, that the disclosure is not so limited and may have general applicability in other aircraft engines as well as in non-aircraft applications, such as other mobile applications and non-mobile industrial, commercial, and residential applications.
All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, aft, etc.) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the disclosure. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to one another. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary. In addition, “a set” as used herein can include any number of a particular element, including only one.
While an aircraft 10 having two turbo-prop engines 16 has been illustrated, embodiments of the disclosure can include any number of engines 16, propeller assemblies 17, or propeller blades 18, or any placement of the engine 16, assemblies 17, or blades 18 relative to the aircraft. Embodiments of the disclosure can further be applied to different aircraft engine 16 types, including, but not limited to, piston-based combustion engines, or electrically-driven engines. Additionally, the rotation 22 of the propeller assemblies 17 or propeller blades 18 is provided for understanding of the embodiments of the disclosure. Embodiments of the disclosure can include alternative directions of rotation 22 of the propeller assemblies 17 or propeller blades 18, or embodiments wherein a set of engines 16 rotate propeller blades 18 in the same or opposing directions.
The exhaust assembly 30 includes the set of exhaust stubs 32, illustrated as two exhaust stubs 32, which can extend from an inlet 34 to an outlet 36. An exhaust collector 38 defines a first portion (A) of the exhaust and is centered along the centerline 20 fluidly coupling a turbine section 40 having a turbine 42 at the inlet 34. An exhaust stub 32 defines a remaining portion (B) of the exhaust extending from the exhaust collector 38 and terminating in the outlet 36.
A reverse flow portion 44 comprised as part of the exhaust collector 38 includes a turn 46. The turn 46 is at least in part defined by an inner radius IR and an outer radius OR proximate the inlet 34 of the exhaust stub 32. The turn 46 is between the inner radius IR and the outer radius OR where the inner radius IR is smaller than the outer radius OR. The exhaust stub 32 together with the exhaust collector 38 define an exhaust conduit 47. The inner radius IR and outer radius OR are the radii for opposing surfaces within the exhaust conduit 47.
A perspective view of the exhaust collector 38 is illustrated in
A flow of exhaust gases illustrated by arrows (G) can move from the turbine section (
A collection of exemplary vortex generators is illustrated in
Some non-limiting examples of cross-sectional shapes include rectangular, triangular, and trapezoidal, and may be at least partially defined by the shape of the leading and trailing surfaces of the vortex generator. Some non-limiting examples of shapes for the leading the trailing surfaces include ramped, wedged, or rounded. For example, the leading surfaces of vortex generators 201, 205, 207, 208 are generally ramped; those of vortex generators 202, 203, 204, 206 are generally wedged; and those of vortex generators 209, 210 are generally rounded. The trailing surfaces of vortex generators 201, 202, 204, 205, 206, 207 are generally ramped; those of vortex generators 203, 208 are generally wedged; and those of vortex generators 209, 210 are generally rounded. The ramped, wedged, or rounded surfaces help maintain a high exhaust gas velocity along the interior surface 152 which can reduce the tendency for dust to accumulate on the interior surface 152.
Some non-limiting examples of planforms include rectangular, trapezoidal, diamond-shaped, kite-shaped, teardrop-shaped, ovoid, elliptical, pentagonal, hexagonal, and heptagonal. For example, the vortex generator 201 has a generally trapezoidal planform, the vortex generators 202, 204 have a generally pentagonal planform, the vortex generator 203 has a generally hexagonal planform, the vortex generators 205, 208 have a generally heptagonal planform, the vortex generator 206 has a generally kite-shaped planform, the vortex generator 207 has a generally rectangular planform, the vortex generator 209 has a generally teardrop-shaped planform, and the vortex generator 210 has a generally elliptical planform.
An exemplary vortex generator 206 includes a generally kite-shaped planform with a wedged leading surface and a ramped trailing surface allows for smaller vortices to initiate at the leading surface and grow along the diverging and expanding side walls that intersect the interior surface 152. The kite-shaped planform presents a small initial disturbance to the exhaust gas flow that grows naturally as a vortex on both side walls.
In any of the above exemplary vortex generators, it is understood that while the drawings may show the vortex generators having sharp corners, edges, and/or transitions with the cooling surface for purposes of illustration, it may be more practical for the corners, edges, and/or transitions to be smoothly radiused or filleted. Furthermore, alternative exemplary vortex generators to the vortex generators illustrated as having smoothly radiused or filleted corners, edges, and/or transitions with the cooling surface may instead have sharp corners, edges, and/or transitions.
It should be understood that any of the exemplary vortex generators described herein are non-limiting examples for vortex generator 50. It should be further understood that the vortex generator 50 would be suited for placement along the inner radius IR and would therefore not be formed exactly as illustrated in
An anti-ice scoop 160 can be integral with, proximate to, or in place of the vortex generator 150. The illustration depicts an anti-ice scoop 160 and a vortex generator 150, however it is contemplated that the anti-ice scoop 160 is formed to be the vortex generator 150. In some aircraft, an engine inlet 162, in which air is received to pass through the engine 16, includes an anti-ice system 164. The anti-ice system 164 can include a conduit 166, coupled to the anti-ice scoop 160, in which hot air is circulated. Small pipes, referred to as snorkels 168, can be placed into exhaust stubs 132 downstream of where the exhaust stub 132 couples to an exhaust collector 138. The snorkels 168 connect the anti-ice scoop 160 to the conduit 166. A flow of combustion gases (G) can flow into at least one of the snorkels 168 via the anti-ice scoop 160 and pass through a delivery pipe 170. The flow of combustion gases (G) can enter the anti-ice scoop 160 due to an orientation of the anti-ice scoop 160 with respect to the flow of combustion gases (G). The combustion gases (G) can then circulate around the inlet 162 through the conduit 166 and exhaust back through a discharge pipe 172 coupled to an exhaust stream (S) for the other of the exhaust stubs 132. Again, the orientation of the anti-ice scoop 160 allows for the combustion gases (G) to discharge into the exhaust stream (S). The method disclosed herein can include scooping a portion of the exhaust gas (G) into the anti-ice scoop 160 and circulating the exhaust gas (G) around the inlet 162.
Installation of vortex generators upstream of the region where flow separation or recirculation can occur will locally energize the boundary layer which reduces separations and pressure losses and therefore improves overall engine performance. An additional benefit is that use of vortex generators can allow for lower radius turns, for example the inner radius (IR) as described herein, resulting in shorter and lighter engines.
In addition, the vortex generators can have integrated anti-ice scoops. The anti-ice scoops can minimize performance loss due to presence of anti-ice snorkels that act as vortex generators, plus the low energy boundary layer can be sucked out of the exhaust to the anti-ice system, further reducing the risk of flow separation.
It should be understood that application of the disclosed design is not limited to turboprop engines, but is applicable to turbine and turboshaft engines as well.
To the extent not already described, the different features and structures of the various embodiments can be used in combination, or in substitution with each other as desired. That one feature is not illustrated in all of the embodiments is not meant to be construed that it cannot be so illustrated, but is done for brevity of description. Thus, the various features of the different embodiments can be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. All combinations or permutations of features described herein are covered by this disclosure.
This written description uses examples to describe aspects of the disclosure described herein, including the best mode, and also to enable any person skilled in the art to practice aspects of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of aspects of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17461548.4 | Jun 2017 | EP | regional |
