Lobe type front duct ejector with mixing strengthening function

Abstract

The invention provides a lobe type front duct ejector with a mixing strengthening function, and belongs to the technical field of aero-engines, lobes and guide plates are sequentially arranged along the circumference and alternately connected to form a lobe ejection device, the lobe ejection device communicates with a first duct and a fan outer duct, and the first duct and the fan outer duct are communicated with each other. After airflow of the first duct and airflow of the fan outer duct pass through the lobe ejection device, efficient ejection of low-speed airflow of the fan outer duct is achieved, the ejection ratio of the engine outer duct can be effectively increased, mixing is enhanced, the mixing distance is shortened, and the problem that airflow mixing at an outlet of the engine outer duct is not uniform is solved.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engines, and in particular to a lobe-type front duct ejector with a mixing enhancement function. Background Art

[0002] With the development of aviation technology, economically affordable multi-purpose, high-range, all-weather combat aircraft have become a development trend. Conventional fixed thermodynamic cycle (mainly fixed bypass ratio) aircraft engines have become increasingly difficult to meet the dual performance requirements of advanced fighters for high unit thrust and low cruise fuel consumption under different working conditions. The variable cycle engine is based on the conventional turbofan engine with a new variable bypass ratio component. By changing the bypass ratio and other key thermodynamic cycle parameters of the engine, it takes into account the flight requirements of lower fuel consumption in the subsonic state and higher unit thrust in the supersonic state. It has become the general trend of propulsion power for modern fighters.

[0003] It can be found that the essential difference between the variable cycle engine and the previous generations of engines and the key to achieving superior performance lies in the ability to change the bypass ratio of the turbofan engine. It mainly relies on a set of new components of the duct ejector to achieve the change of the bypass ratio. The duct ejector consists of two main components: the front duct ejector and the rear duct ejector. The front duct ejector draws a stream of air at the outlet of the first duct to eject the airflow of the fan's outer duct, increase the flow rate of the engine's outer duct airflow, and achieve wide range adjustment of the bypass ratio. In the conventional front duct ejector, the airflow of the first duct and the airflow of the fan's outer duct can only be mixed by inducing low-intensity spanwise vortices, resulting in low mixing efficiency of the two airflows, and it is difficult to mix them evenly within the limited axial length of the engine. Summary of the invention

[0004] In order to solve the problems in the above-mentioned prior art, the present invention provides a lobe-type front duct ejector with a mixing enhancement function. The invention arranges lobes and guide plates in a circle and connects them alternately to form a lobe ejector device. The lobe ejector device is connected to the first duct and the fan outer duct respectively. When the airflow of the first duct and the airflow of the fan outer duct pass through the lobe ejector device, the low-speed airflow of the fan outer duct is efficiently ejected, which can effectively improve the ejection ratio of the engine outer duct, enhance mixing, shorten the mixing distance, and improve the problem of uneven mixing of the airflow at the engine outer duct outlet. To achieve the above purpose, the technical scheme is as follows:

[0005] The present invention provides a lobe-type front duct ejector with a mixing enhancement function, the ejector comprising: a first duct, a fan outer duct, an engine outer duct and a lobe ejector device;

[0006] The outlet of the first duct is connected to the crest inlet of the lobe ejection device,

[0007] The trough inlet of the lobe ejector is connected to the fan outer duct in a nested manner.

[0008] The outlet of the lobe ejector is connected to the engine duct in a nested manner.

[0009] The lobe ejection device comprises a lobe and a guide plate.

[0010] The lobes and the guide plates are arranged in sequence along the circumference and are alternately connected.

[0011] Optionally, the lobe includes: a lobe peak plate, a lobe trough plate and a lobe side plate;

[0012] The shape of the lobe crest plate includes: rectangular, rounded rectangular and arched;

[0013] The shapes of the lobe and trough plates include: semi-ellipse, rounded rectangle and arch;

[0014] The lobe peak plate is connected to the upper end of the lobe side plate, and the lobe trough plate is connected to the lower end of the lobe side plate.

[0015] Optionally, the shape of the guide plate includes: rectangle, rounded rectangle and arch.

[0016] Optionally, the lobe peak plate is tangentially connected to the top of the guide plate.

[0017] Optionally, the airflow of the first duct reaches the engine outer duct through the channel formed by the lobe peak plate and the guide plate; the airflow of the fan outer duct reaches the engine outer duct through the channel formed by the lobe trough plate.

[0018] Optionally, the lobes and the guide plates are arranged in sequence along the circumference and alternately connected in number of not less than 2 pairs.

[0019] Optionally, the relationship between the lobe height h of the lobe and the inlet height H of the fan duct is:

[0020]

[0021] Optionally, the relationship between the length L of the guide plate and the inlet height H of the fan duct is:

[0022]

[0023] Optionally, the relationship between the peak width d of the lobe ejection device and the lobe trailing edge circumference S of the lobe ejection device is:

[0024]

[0025] Optionally, the mixing and strengthening process of the ejector includes:

[0026] The airflow of the first duct reaches the outer duct of the engine through the channel formed by the lobe peak plate and the guide plate, thereby obtaining multiple high-speed airflows;

[0027] The airflow of the fan duct reaches the engine duct through the channel formed by the lobe and trough plate, and obtains multiple low-speed airflows;

[0028] According to the multiple high-speed airflows and the multiple low-speed airflows, a large-scale flow vortex structure is induced at the outlet of the lobe ejector to achieve the mixing enhancement function of the ejector.

[0029] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0030] The above scheme forms a lobe ejection device by arranging lobes and guide plates alternately along the circumference. The lobe ejection device is connected to the first duct and the fan outer duct respectively. When the airflow of the first duct and the airflow of the fan outer duct pass through the lobe ejection device, the low-speed airflow of the fan outer duct is efficiently ejected, which can effectively improve the ejection ratio of the engine outer duct, enhance mixing, shorten the mixing distance, and improve the problem of uneven mixing of the airflow at the engine outer duct outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a three-dimensional structural schematic diagram of an embodiment of a lobe-type front duct ejector with mixing enhancement function of the present invention;

[0033] Figure 2 2. It is a front view schematic diagram of an embodiment of a lobe-type front duct ejector with mixing enhancement function of the present invention;

[0034] Figure 3 It is a three-dimensional structural schematic diagram of a lobe ejector device of an embodiment of a lobe-type front duct ejector with mixing enhancement function of the present invention;

[0035] Figure 4 It is a schematic diagram of the circumferential arrangement of the lobe ejector devices of the lobe type front duct ejector embodiment with mixing enhancement function of the present invention;

[0036] Figure 5It is a flow chart of the mixing enhancement process of the ejector of the embodiment of the lobe-type front duct ejector with mixing enhancement function of the present invention;

[0037] Figure 6 It is a simulation diagram of the flow vortex system evolution of an embodiment of the lobe-type front duct ejector with mixing enhancement function of the present invention.

[0038] Explanation of the numbers in the figure: first duct 1, fan outer duct 2, engine outer duct 3, lobe ejector device 4, lobe 41, guide plate 42, lobe peak plate 411, lobe trough plate 412, lobe side plate 413. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0040] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0041] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0042] This embodiment takes the typical variable cycle engine front duct ejector as an example. The airflow enters the engine after deceleration through the intake duct and is compressed by the fan. At the fan outlet, the airflow passes through the first diversion section and is divided into the airflow flowing to the fan outer duct 2 and the airflow flowing to the core drive fan. The airflow entering the core drive fan is diverted again at the outlet through the second diversion section, and part of the flow enters the first duct 1, and is mixed with the airflow of the fan outer duct 2 in the front duct ejector, and flows to the engine outer duct 3.

[0043] like Figure 1 The three-dimensional structural diagram of the embodiment of the lobe-type front duct ejector with mixing enhancement function of the present invention is shown in FIG. Figure 2 The front view schematic diagram of an embodiment of a lobe-type front duct ejector with a mixing enhancement function of the present invention is shown. The present invention provides a lobe-type front duct ejector with a mixing enhancement function, the ejector comprising: a first duct 1, a fan outer duct 2, an engine outer duct 3 and a lobe ejector device 4,

[0044] The outlet of the first duct 1 is connected to the wave crest inlet of the wave lobe ejection device 4.

[0045] The trough inlet of the lobe ejection device 4 is connected to the fan outer duct 2 in a nested manner.

[0046] The outlet of the lobe ejection device 4 is connected to the engine duct 3 in a nested manner.

[0047] like Figure 3 The three-dimensional structural schematic diagram of the lobe ejector device of the lobe type front duct ejector embodiment with mixing enhancement function of the present invention is shown, and the lobe ejector device 4 includes a lobe 41 and a guide plate 42;

[0048] The lobes 41 and the guide plates 42 are arranged in sequence along the circumference and are alternately connected.

[0049] Specifically, Figure 4 The schematic diagram of the circumferential arrangement of the lobe ejector device of the lobe type front duct ejector embodiment with mixing enhancement function of the present invention is shown, and the lobe 41 includes: a lobe peak plate 411, a lobe trough plate 412 and a lobe side plate 413;

[0050] The shapes of the lobe peak plate 411 include: rectangular, rounded rectangular and arched;

[0051] The shapes of the lobe and trough plate 412 include: semi-ellipse, rounded rectangle and arch;

[0052] The lobe peak plate 411 is connected to the upper end of the lobe side plate 413 , and the lobe trough plate 412 is connected to the lower end of the lobe side plate 413 .

[0053] Specifically, the shapes of the guide plate 402 include: rectangle, rounded rectangle and arch.

[0054] Specifically, the lobe peak plate 411 is tangentially connected to the top of the guide plate 42 .

[0055] Furthermore, the number of the lobes 41 and the guide plates 42 that are alternately connected and arranged in sequence along the circumference is not less than 2 pairs.

[0056] Specifically, the airflow of the first duct 1 reaches the engine outer duct 3 through the channel formed by the lobe peak plate 411 and the guide plate 42 ; the airflow of the fan outer duct 2 reaches the engine outer duct 3 through the channel formed by the lobe trough plate 412 .

[0057] Specifically, Figure 5 The mixing enhancement process flow chart of the ejector of the embodiment of the lobe-type front duct ejector with mixing enhancement function of the present invention is shown, and the mixing enhancement process of the ejector includes:

[0058] The airflow of the first duct 1 reaches the engine outer duct 3 through the channel formed by the lobe peak plate 411 and the guide plate 42, and obtains multiple high-speed airflows;

[0059] The airflow of the fan duct 2 reaches the engine duct 3 through the channel formed by the lobe trough plate 412, and obtains multiple low-speed airflows;

[0060] According to the multiple high-speed airflows and the multiple low-speed airflows, a large-scale flow vortex structure is induced at the outlet of the lobe ejector 4 to achieve the mixing and enhancement function of the ejector.

[0061] Furthermore, by providing the guide plate 42 , the flow direction of the airflow in the first duct 1 can be changed, and the lobe ejection device 4 can increase the secondary flow, further improve the strength of the flow toward the vortex system, and increase the ejection effect of the airflow in the first duct 1 .

[0062] like Figure 6 The simulation diagram of the flow vortex system evolution of the embodiment of the lobe type front duct ejector with mixing enhancement function of the present invention is shown. Through simulation analysis, it can be known that the contact area between the airflow in the first duct 1 and the airflow in the fan outer duct 2 is increased by adding the lobe ejector device 4. In addition to the spanwise vortex generated by the original ejection, the shear layer detached from the lobe trailing edge of the lobe ejector device 4 rolls up a large-scale flow vortex system, forcing the low-speed airflow in the fan outer duct 2 and the high-speed airflow in the first duct 1 to exchange momentum and energy, thereby realizing accelerated jet mixing with minimal total pressure loss and within the shortest possible mixing length.

[0063] Specifically, the relationship between the lobe height h of the lobe 41 and the inlet height H of the fan duct 2 is:

[0064]

[0065] Specifically, the relationship between the length L of the guide plate 42 and the inlet height H of the fan duct 2 is:

[0066]

[0067] Specifically, the relationship between the peak width d of the lobe ejection device 4 and the lobe trailing edge circumference S of the lobe ejection device 4 is:

[0068]

[0069] Furthermore, the calculation method of the lobe trailing edge perimeter S is as shown in formula (1):

[0070] S=a+2c+d (1)

[0071] Where S is the circumference of the lobe trailing edge; d is the arc length of the lobe crest plate, that is, the width of the lobe crest plate; a is the arc length of the lobe trough plate, that is, the width of the lobe trough plate; c is the height of the lobe side plate.

[0072] The present invention provides a lobe-type front duct ejector with a mixing enhancement function. The invention forms a lobe ejector device 4 by arranging lobes 41 and guide plates 42 in sequence along a circle and alternately connecting them. The lobe ejector device 4 is respectively connected to the first duct 1 and the fan outer duct 2. When the airflow of the first duct 1 and the airflow of the fan outer duct 2 pass through the lobe ejector device, the low-speed airflow of the fan outer duct 2 is efficiently ejected, which can effectively improve the ejection ratio of the engine outer duct 3, enhance mixing, shorten the mixing distance, and improve the problem of uneven mixing of the airflow at the outlet of the engine outer duct 3.

[0073] It is to be understood that the present invention is described by the above embodiments and should not be construed as limiting the embodiments of the present invention and the scope of the present invention. It is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A lobe-type front duct ejector with mixing enhancement function, characterized in that: The ejector comprises: a first duct, a fan outer duct, an engine outer duct and a lobe ejector device; The outlet of the first duct is connected to the crest inlet of the lobe ejection device, The trough inlet of the lobe ejection device is connected to the fan outer duct in a nested manner. The outlet of the lobe ejection device is connected to the engine duct in a nested manner. The lobe ejection device comprises a lobe and a guide plate. The lobes and the guide plates are arranged in sequence along the circumference and are alternately connected.

2. The lobe-type front duct ejector with mixing enhancement function according to claim 1 is characterized in that: The lobe includes: a lobe peak plate, a lobe trough plate and a lobe side plate; The shapes of the lobe and crest plates include: rectangle, rounded rectangle and arch; The shapes of the lobe and trough plates include: semi-ellipse, rounded rectangle and arch; The lobe peak plate is connected to the upper end of the lobe side plate, and the lobe trough plate is connected to the lower end of the lobe side plate.

3. The lobe-type front duct ejector with mixing enhancement function according to claim 1 is characterized in that: The shapes of the guide plate include: rectangle, rounded rectangle and arch.

4. The lobe-type front duct ejector with mixing enhancement function according to claim 2 is characterized in that: The lobe peak plate is tangentially connected to the top of the guide plate.

5. The lobe-type front duct ejector with mixing enhancement function according to claim 4 is characterized in that: The airflow of the first duct reaches the engine outer duct through the channel formed by the lobe peak plate and the guide plate; the airflow of the fan outer duct reaches the engine outer duct through the channel formed by the lobe trough plate.

6. The lobe-type front duct ejector with mixing enhancement function according to claim 1, characterized in that: The lobes and the guide plates are arranged in sequence along the circumference and connected alternately in number of not less than 2 pairs.

7. The lobe-type front duct ejector with mixing enhancement function according to claim 1, characterized in that: The relationship between the lobe height h of the lobe and the inlet height H of the fan duct is:

8. The lobe-type front duct ejector with mixing enhancement function according to claim 1 is characterized in that: The relationship between the length L of the guide plate and the inlet height H of the fan duct is:

9. The lobe-type front duct ejector with mixing enhancement function according to claim 1, characterized in that: The relationship between the peak width d of the lobe ejection device and the perimeter S of the lobe trailing edge of the lobe ejection device is:

10. The lobe-type front duct ejector with mixing enhancement function according to claim 5, characterized in that: The mixing and strengthening process of the ejector includes: The airflow of the first duct reaches the engine outer duct through the channel formed by the lobe peak plate and the guide plate, thereby obtaining multiple high-speed airflows; The airflow of the fan duct reaches the engine duct through the channel formed by the lobe and trough plates to obtain multiple low-speed airflows; According to the multiple high-speed airflows and the multiple low-speed airflows, a large-scale flow vortex structure is induced at the outlet of the lobe ejector to achieve the mixing enhancement function of the ejector.

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