A staggered rear duct ejector mixer and afterburner

Abstract

The present invention provides a staggered rear duct ejector mixer, comprising a diverter ring, a rear duct ejector mixer and an actuating device, wherein the guide vanes of the rear duct ejector mixer and the diverter ring guide vanes are staggered. The present invention adjusts the rear duct ejector mixer so that the variable cycle engine can meet the area requirements at the mixer outlet cross section under different working modes. In a medium bypass ratio or large bypass ratio working mode, the internal high-temperature airflow and part of the external low-temperature airflow form a strong flow vortex downstream of the rear duct ejector mixer, thereby enhancing the mixing effect of the internal high-temperature airflow and part of the external low-temperature airflow in the internal channel. In a small bypass ratio working mode, the guide vanes of the rear duct ejector mixer and the diverter ring guide vanes are parallel, effectively reducing the flow loss of the rear duct ejector mixer. The present invention also provides an afterburner with a staggered rear duct ejector mixer.

Description

Technical Field

[0001] The invention belongs to the field of aerospace technology, and in particular relates to a rear duct ejector mixer and an afterburner combustion chamber applied to a variable cycle engine. Background Art

[0002] In order to solve the contradiction between low fuel consumption and high thrust-to-weight ratio of aircraft engines, the concept of variable cycle engine came into being. Since variable cycle engines can change the parameters of aerodynamic thermodynamic cycle by changing the geometric structure of components, they have the advantages of multiple bypass ratio engines and can work in different modes under different bypass ratio conditions. The rear duct ejector mixer is a key component of the variable cycle engine. Through the coordinated work of the rear duct ejector mixer, the mode conversion valve and the front duct ejector, the mode conversion under different working conditions can be achieved. At the same time, the rear duct ejector mixer is also crucial to the afterburner combustion organization of the variable cycle engine. After years of exploration, many rear duct ejector mixers have been developed at home and abroad, but the currently disclosed invention patents for rear duct ejector mixers mostly focus on the area adjustment scheme of the rear duct ejector mixer, while ignoring the mixing performance of the internal and external duct airflows. Summary of the invention

[0003] In response to the above problems, the present invention provides a staggered rear duct ejector mixer for a variable cycle engine, which can not only realize the area adjustment function, but also take into account the mixing effect of the inner and outer duct airflows, thereby providing favorable conditions for organizing combustion in the afterburner.

[0004] In one aspect of the present invention, there is provided a staggered rear duct ejector mixer, comprising: a central cone, a casing, a flow divider ring circumferentially disposed between the central cone and the casing, and a rear duct ejector mixer circumferentially disposed between the central cone and the flow divider ring;

[0005] The axial position of the front end of the diverter ring is close to the front end of the central cone, so that the gas flow area between the central cone and the casing is divided into an outer area between the diverter ring and the casing and an inner area between the diverter ring and the central cone.

[0006] Among them, the diverter ring is provided with an air flow hole and a guide plate circumferentially adjacent to the air flow hole, and the rear duct ejector mixer is provided with a guide plate corresponding to the air flow hole. The guide plate is constructed to be adjustable at an angle θ relative to the air flow hole, so as to adjust the air in the outer duct area to enter the air flow channel of the inner duct area through the air flow hole.

[0007] Preferably, the angle θ of the guide plate relative to the air flow hole is configured as follows:

[0008] In a medium or large bypass ratio operating mode, increasing the angle θ, thereby increasing the flow rate from the outer bypass area to the inner bypass area through the air flow channel according to design requirements; and

[0009] In a small bypass ratio working mode, the angle θ is reduced, thereby reducing or closing the flow from the outer bypass area to the inner bypass area through the air flow channel according to design requirements.

[0010] Preferably, the staggered rear duct ejector mixer further comprises:

[0011] The actuating device is configured to adjust the angle θ of the guide vane relative to the airflow hole, so that when the angle θ is increased, the airflow channel is opened and the afterburner enters a medium or large bypass ratio operating mode, and when the angle θ is decreased, the airflow channel is reduced or closed and the afterburner enters a small bypass ratio operating mode.

[0012] Preferably, the splitter ring has a splitter ring leading edge on the front side of the air flow hole, which has a first inclination angle α with the flow direction, and the first inclination angle α is constructed to make the inner region tilt toward the outer duct region at the leading edge of the splitter ring, and the rear duct ejector mixer has a rear duct ejector mixer leading edge on the front side of the guide vane, which has a second inclination angle β with the flow direction, and the second inclination angle β is constructed to make the outer duct region tilt toward the inner region at the leading edge of the rear duct ejector mixer.

[0013] Preferably, the plurality of air flow holes are evenly distributed on the diverter ring along the circumferential direction, the plurality of guide vanes are evenly distributed on the rear duct ejector mixer along the circumferential direction, and the plurality of air flow holes and the plurality of guide vanes are staggered with each other.

[0014] Preferably, the guide plate is constructed to have an inclination angle γ with the flow direction, and the inclination angle γ is constructed to make the inner area tilt toward the outer area at the guide plate, thereby guiding the airflow in the inner area to increase the radial velocity, so that the airflow velocity vector of the inner area is toward the direction of the outer area.

[0015] Preferably, the side of the guide vane facing the outer region is constructed to have an arc surface with the same radius as that of the diverter ring, so as to improve the sealing between the guide vane and the air flow hole when the air flow channel is closed.

[0016] Preferably, the side of the guide vane facing the inner area is constructed as an arc surface with a smaller radius than the side facing the inner area, thereby expanding the contact area between the inner high-temperature airflow and the outer low-temperature airflow along both sides of the guide vane, and promoting the shear layer of the inner high-temperature airflow and the outer low-temperature airflow to generate a flow vortex.

[0017] Preferably, partitions are vertically arranged on both sides of the guide plate in the circumferential direction, and the partitions are configured to be sealed between the guide plate and the guide plate when the guide plate is opened relative to the air flow hole.

[0018] In another aspect of the present invention, an afterburner is provided, comprising the staggered post-duct ejector mixer as described in any of the foregoing embodiments.

[0019] Therefore, the beneficial technical effects of the present invention include at least one of the following:

[0020] When the afterburner bypass ratio varies greatly, the rear duct ejector mixer is adjusted by the actuator to adjust the inner and outer bypass airflow channel areas under different bypass ratio working modes. This can meet the variable cycle engine's demand for area changes under different working modes, and introduce the outer bypass airflow into the inner bypass for mixing according to the designed ratio.

[0021] In the medium or large bypass ratio working mode, the guide vanes of the rear duct ejector mixer and the diverter ring guide vanes are arranged alternately, so that the internal high-temperature airflow and the introduced external low-temperature airflow are staggered and mixed, increasing the contact area between the high-temperature airflow in the internal area and the external low-temperature airflow entering the internal area through the airflow channel, and strengthening the mixing of the internal and external airflows.

[0022] Under the medium or large bypass ratio working mode, the guide vanes of the rear duct ejector mixer are inclined toward the center, and the staggered rear duct ejector mixer guide vanes and the diverter ring guide vanes cooperate with each other to form a larger angle θ. The internal high-temperature airflow and part of the external low-temperature airflow form a strong flow vortex in the downstream flow field, further strengthening the mixing of the internal and external airflows, so that the temperature distribution after the internal airflow and part of the external airflow are uniform.

[0023] In the small bypass ratio working mode, the guide vanes of the rear duct ejector mixer are tilted away from the center, so that the guide vanes of the rear duct ejector mixer and the guide vanes of the diverter ring are parallel, which effectively reduces the flow loss of the rear duct ejector mixer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application, but do not constitute a limitation on the technical solution of the present application.

[0025] Figure 1 A schematic diagram of the cross-sectional structure and the working principle of the afterburner combustion chamber of the variable cycle engine to which the present invention is applied when the afterburner combustion chamber is in a medium or large bypass ratio working mode parallel to the axial direction;

[0026] Figure 2A schematic diagram of the cross-sectional structure parallel to the axial direction and a schematic diagram of the working principle of the afterburner combustion chamber of the variable cycle engine to which the present invention is applied when the afterburner combustion chamber is in a small bypass ratio working mode;

[0027] Figure 3 A supplementary schematic diagram of the working principle of the afterburner combustion chamber of a variable cycle engine using the present invention when it is in a medium or large bypass ratio working mode;

[0028] Figure 4 It is a schematic diagram of the three-dimensional structure of the full-annular rear duct ejector mixer and the splitter ring of the present invention;

[0029] Figure 5 It is a schematic diagram of the three-dimensional structure of the full-annular rear duct ejector mixer of the present invention;

[0030] Figure 6 A schematic diagram of the three-dimensional structure of the guide vane of the first rear duct ejector mixer provided by the present invention;

[0031] Figure 7 A schematic diagram of the three-dimensional structure of the guide vane of the second rear duct ejector mixer provided by the present invention;

[0032] Figure 8 A schematic diagram of the three-dimensional structure of a rear ducted ejector mixer using the second guide vane of the rear ducted ejector mixer provided by the present invention;

[0033] Fig. 9 A schematic diagram of the three-dimensional structure of a splitter ring designed to match the rear duct ejector mixer provided by the present invention;

[0034] Fig.10 Schematic diagram of the flow field downstream of the rear duct ejector mixer, obtained by numerically calculating the 45° fan-shaped fluid domain using commercial CFD software;

[0035] Description of reference numerals:

[0036] 1- Receiver;

[0037] 2-rear duct ejector mixer; 21-front edge of rear duct ejector mixer; 22-hinge; 23-guide vane;

[0038] 3-diverter ring; 31-diverter ring front edge; 32-drainage plate; 33-airflow hole; 34-diverter ring rear section;

[0039] 4-Center cone;

[0040] 5-turbine casing;

[0041] 6- turbine disc;

[0042] a-internal area; b-external area; c-internal and external airflow mixing area; d-external unmixed area; e-stream vortex;

[0043] Side A: the guide vane surface facing the outer area; Side B: the guide vane surface facing the inner area;

[0044] α-the first inclination angle of the leading edge of the splitter ring; β-the second inclination angle of the leading edge of the rear duct ejector mixer; γ-the inclination angle of the splitter ring guide vane; θ-the adjustment angle of the guide vane; L-the axial distance from the rear duct ejector mixer; DETAILED DESCRIPTION

[0045] Various exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is not intended to be any limitation on the present invention and its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention clear and complete and to fully express the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps described in these embodiments should be interpreted as being merely exemplary and not as a limitation.

[0046] like Figure 1-3 As shown, in one aspect of the present invention, a staggered rear duct ejector mixer is provided, comprising: a central cone 4, a casing 1, a flow divider ring 3 and a rear duct ejector mixer 2. The central cone 4 is connected to the axial rear side of the turbine disk 6, and correspondingly, the flow divider ring 3 and the rear duct ejector mixer 2 are connected to the axial rear side of the turbine casing 5.

[0047] The flow divider ring 3 is disposed around the center cone 4 and the casing 1, and divides the gas flow area in the afterburner into an outer region b between the flow divider ring 3 and the casing 1 and an inner region a between the flow divider ring 3 and the center cone 4. Fig. 9 As shown, the diverter ring 3 comprises a diverter ring front edge 31 , a guide plate 32 , air flow holes 33 arranged alternately with the guide plate 32 , and a diverter ring rear section 34 .

[0048] Then the duct ejector mixer 2 is arranged around the flow divider ring 3 and the casing 1, and as shown in FIG. Figure 5 As shown, the rear duct-injector mixer 2 is provided with a rear duct-injector mixer leading edge 21 and a guide vane 23 corresponding to the air flow hole 33 , and a hinge 22 for rotating the guide vane 23 .

[0049] Thus, the present invention forms an airflow channel in the area where the splitter ring 3 and the rear duct ejector mixer 2 are located, which is used to connect the inner region a and the outer region b. In addition, the present invention adjusts the angle θ of the guide vane 23 by setting an actuating device. When the angle θ of the guide vane 23 is increased, the airflow channel is opened and the afterburner enters a medium bypass ratio working mode. When the angle θ of the guide vane 23 is decreased, the airflow channel is reduced or closed and the afterburner enters a small bypass ratio working mode.

[0050] That is, the staggered rear duct ejector mixer provided by the present invention can control the working mode of the variable cycle engine by adjusting the angle θ of the guide vane 23: in the medium or large bypass ratio working mode, by adjusting the angle θ of the guide vane 23, the air flow channel is opened, the inner and outer duct channel areas are changed, the flow of the outer duct area b is controlled, and the flow entering the inner duct and the remaining flow of the outer duct area b are allocated according to design requirements; in the small bypass ratio working mode, the air flow channel is narrowed or closed by adjusting the guide vane 23.

[0051] In some embodiments, the angle θ of the guide vane 23 relative to the air flow hole 33 can be adjusted in a range of 0-60°, so as to meet the design requirements of different working modes of the variable cycle engine.

[0052] Preferably, the splitter ring 3 has a splitter ring leading edge 31 at a first inclination angle α with the flow direction on the front side of the airflow hole 33, and the first inclination angle α is configured to make the inner region a tilted toward the outer region b at the splitter ring leading edge 31. The rear duct ejector mixer 2 has a rear duct ejector mixer leading edge 21 at a second inclination angle β with the flow direction on the front side of the guide vane 23, and the second inclination angle β is configured to make the outer region b tilted toward the inner region a at the rear duct ejector mixer leading edge 21.

[0053] Therefore, the beneficial technical effects brought about by setting the first inclination angle α and the second inclination angle β of the present invention include:

[0054] The second inclination angle β of the leading edge 21 of the rear duct ejector mixer is set to enable the outer duct airflow to have a radial velocity component in the direction of the center, thereby avoiding separation of the airflow caused by the rear duct ejector adjustment plate when the angle is too large;

[0055] The second inclination angle β of the present invention enables the airflow to have a radial velocity component in the direction of the center, and can introduce a part of the inner airflow through the radial velocity on the basis of introducing a part of the airflow through the pressure difference force, thus also having the effect of increasing the amount of air introduced into the inner part; and

[0056] The second inclination angle β is set so that the outer duct airflow has a radial velocity component toward the center, and the introduced outer duct airflow is closer to the central cone 4 than the airflow introduced by the general rear duct ejector. The first inclination angle α is set so that the inner duct airflow has a radial velocity component in the outward direction. The combination of the two can increase the mixing area of ​​the inner and outer duct airflows.

[0057] In a preferred embodiment, the first inclination angle α is 2-15°, and the second inclination angle β is 2-15°, so as to obtain a better mixing effect and reduce the aerodynamic loss of the afterburner.

[0058] Preferably, in one embodiment of the present invention, the rear duct ejector mixer 2 and the diverter ring 3 cooperate with the casing 1 to form a channel that first expands and then contracts, and the guide vane 23 of the rear duct ejector mixer 2 is set in the tapering section, thereby increasing the flow rate of the outer duct airflow from the outer duct area b into the inner duct area a.

[0059] like Figure 4-5 As shown, preferably, the plurality of air flow holes 33 are evenly distributed on the splitter ring 3 along the circumferential direction, the plurality of guide vanes 32 are evenly distributed on the rear duct ejector mixer 2 along the circumferential direction, and the plurality of air flow holes 33 and the plurality of guide vanes 32 are staggered with each other.

[0060] The staggered multiple air flow holes 33 and multiple guide plates 32 can improve the uniformity of the air flow in the outer area b entering the inner area a through the air flow channel, making the temperature, velocity, pressure and other parameters of the inner area a of the afterburner more uniform, thereby improving the mixing and combustion efficiency.

[0061] Preferably, the guide plate 32 is constructed to have an inclination angle γ with the flow direction, and the inclination angle γ is constructed to make the inner area a tilt toward the outer area b at the guide plate 32, thereby guiding the airflow in the inner area a to increase the radial velocity, so that the airflow velocity vector of the inner area a is toward the direction of the outer area b.

[0062] In a preferred embodiment, the inclination angle γ is in the range of 5-22°, thereby ensuring that the airflow in the inner region has a sufficient radial velocity under the action of the inclination angle γ, and preventing strong aerodynamic losses or gas separation caused by excessive inclination angle γ.

[0063] like Figure 6 As shown, preferably, the side of the guide vane 23 facing the outer circumference area b is constructed to have an arc surface with the same radius as the diverter ring 3, so as to improve the sealing between the guide vane 23 and the airflow hole 33 when the airflow channel is closed.

[0064] Preferably, the side of the guide vane 23 facing the inner region a is constructed as an arc surface with a smaller radius than the side facing the inner region a, thereby expanding the contact area between the inner high-temperature airflow and the outer low-temperature airflow along both sides of the guide vane 23, and promoting the shear layer of the inner high-temperature airflow and the outer low-temperature airflow to generate a flow vortex.

[0065] like Figure 7 and Figure 8 As shown, preferably, baffles are vertically provided on both sides of the guide plate 23 in the circumferential direction, and the baffles are configured to be sealed between the guide plate 32 and the guide plate 23 when the guide plate 23 is opened relative to the air flow hole 33 .

[0066] Based on the above embodiments, the beneficial technical effects of the present invention include at least one of the following:

[0067] When the bypass ratio of the afterburner chamber varies greatly, the rear duct ejector mixer 2 is adjusted by the actuator to adjust the inner and outer bypass airflow channel areas under different bypass ratio working modes, which can meet the variable cycle engine's demand for area changes under different working modes, and introduce the outer bypass airflow into the inner bypass for mixing according to the designed ratio.

[0068] like Fig.10 As shown, in the medium or large bypass ratio working mode, the guide vanes 23 of the rear duct ejector mixer 2 and the guide vanes 32 of the diverter ring 3 are arranged alternately, so that the inner high-temperature airflow and the introduced outer low-temperature airflow are staggered and mixed, increasing the contact area between the inner high-temperature airflow and the outer low-temperature airflow entering the inner through the airflow channel, and strengthening the mixing of the inner and outer airflows.

[0069] In the medium or large bypass ratio working mode, the guide vanes 23 of the rear duct ejector mixer 2 are inclined toward the center, and the staggered guide vanes 23 of the rear duct ejector mixer 2 and the guide vanes 32 of the diverter ring 3 cooperate with each other to form a larger angle θ. The internal high-temperature airflow and part of the external low-temperature airflow form a strong flow vortex e in the downstream flow field, further strengthening the mixing of the internal and external airflows, so that the temperature distribution after the internal airflow and part of the external airflow are even.

[0070] In the small bypass ratio working mode, the guide vane 23 of the rear duct ejector mixer 2 is tilted away from the center, so that the guide vane 23 of the rear duct ejector mixer 2 and the guide vane 32 of the diverter ring 3 are parallel, which effectively reduces the flow loss of the rear duct ejector mixer 2.

[0071] In another aspect of the present invention, an afterburner is provided, comprising a staggered post-duct ejector mixer as described in any one of the above embodiments.

[0072] So far, some specific embodiments of the present invention have been described in detail by way of examples, but those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A staggered rear duct ejector mixer, characterized in that: include: A central cone (4), a casing (1), a flow divider ring (3) circumferentially arranged between the central cone (4) and the casing (1), and a rear duct ejector mixer (2) circumferentially arranged between the central cone (4) and the flow divider ring (3); The axial position of the front end of the diverter ring (3) is close to the front end of the central cone (4), thereby dividing the gas flow area between the central cone (4) and the casing (1) into an outer region (b) located between the diverter ring (3) and the casing (1) and an inner region (a) located between the diverter ring (3) and the central cone (4); The splitter ring (3) is provided with an airflow hole (33) and a guide plate (32) circumferentially adjacent to the airflow hole (33); the rear duct ejector mixer (2) is provided with a guide plate (23) corresponding to the airflow hole (33); the guide plate (23) is configured to be adjustable in angle θ relative to the airflow hole (33), so as to adjust the airflow passage of the air in the outer duct area (b) into the inner duct area (a) through the airflow hole (33); The splitter ring (3) has a splitter ring leading edge (31) at the front side of the air flow hole (33) and has a first inclination angle α with the flow direction, and the first inclination angle α is configured to make the inner region (a) tilt toward the outer region (b) at the splitter ring leading edge (31), and the rear duct ejector mixer (2) has a rear duct ejector mixer leading edge (21) at the front side of the guide vane (23) and has a second inclination angle β with the flow direction, and the second inclination angle β is configured to make the outer region (b) tilt toward the inner region (a) at the rear duct ejector mixer leading edge (21).

2. The staggered post-duct ejector mixer according to claim 1, characterized in that: The angle θ of the guide plate (23) relative to the air flow hole (33) is configured as follows: In a medium or large bypass ratio working mode, the angle θ is increased, thereby increasing the flow rate from the outer bypass area (b) to the inner bypass area (a) through the air flow channel according to design requirements; as well as In a small bypass ratio working mode, the angle θ is reduced, thereby reducing or closing the flow from the outer bypass area (b) into the inner bypass area (a) through the air flow channel according to design requirements.

3. The staggered post-duct ejector mixer according to claim 1, characterized in that: Also includes: The actuating device is configured to adjust the angle θ of the guide vane (23) relative to the airflow hole (33), so that when the angle θ is increased, the airflow channel is opened and the afterburner enters a medium or large bypass ratio working mode, and when the angle θ is decreased, the airflow channel is reduced or closed and the afterburner enters a small bypass ratio working mode.

4. The staggered rear duct ejector mixer according to claim 1, characterized in that: The plurality of air flow holes (33) are evenly distributed on the diverter ring (3) along the circumferential direction, the plurality of guide plates (32) are evenly distributed on the rear duct ejector mixer (2) along the circumferential direction, and the plurality of air flow holes (33) and the plurality of guide plates (32) are arranged in an alternating manner.

5. The staggered rear duct ejector mixer according to claim 4, characterized in that: The guide plate (32) is constructed to have an inclination angle γ with the flow direction, and the inclination angle γ is constructed to make the inner region (a) tilt toward the outer region (b) at the guide plate (32), thereby guiding the airflow in the inner region (a) to increase the radial velocity, so that the airflow velocity vector of the inner region (a) is directed toward the outer region (b).

6. The staggered post-duct ejector mixer according to claim 1, characterized in that: The side of the guide plate (23) facing the outer cladding area (b) is constructed to have an arc surface with the same radius as the diverter ring (3), thereby improving the sealing performance between the guide plate (23) and the air flow hole (33) when the air flow channel is closed.

7. The staggered post-duct ejector mixer according to claim 6, characterized in that: The side of the guide vane (23) facing the inner region (a) is constructed as an arc surface with a smaller radius than the side facing the outer region (b), thereby expanding the contact surface between the inner high-temperature airflow and the outer low-temperature airflow along both sides of the guide vane (23), and promoting the generation of stream vortices in the shear layers of the inner high-temperature airflow and the outer low-temperature airflow.

8. The staggered post-duct ejector mixer according to claim 1, characterized in that: The guide plate (23) is vertically provided with partitions on both sides in the circumferential direction, and the partitions are configured to be sealed between the guide plate (32) and the guide plate (23) when the guide plate (23) is opened relative to the air flow hole (33).

9. An afterburner, characterized in that: It comprises the staggered rear duct ejector mixer as described in any one of claims 1 to 8.

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