A lobed forepass duct ejector with blending enhancement function

Abstract

The application provides a lobed front bypass ejector with blending enhancement function and belongs to the technical field of aero-engines.The lobed and guide plates are alternately connected in sequence along the circumference to form a lobed ejector device, the lobed ejector device is communicated with a first bypass and a fan outer bypass, after the airflow of the first bypass and the airflow of the fan outer bypass pass through the lobed ejector device, the low-speed airflow of the fan outer bypass is efficiently ejected, the ejection ratio of the engine outer bypass can be effectively improved, the blending is strengthened, the blending distance is shortened, and the problem of uneven blending of the airflow at the outlet of the engine outer bypass is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, and particularly relates to a lobed forward duct ejector with mixing enhancement function. BACKGROUND

[0002] With the development of aviation technology, a multipurpose, high-range and all-weather combat aircraft with economic affordability has become a development trend, and a conventional fixed thermal cycle (mainly a fixed bypass ratio) aero-engine has been increasingly difficult to meet the dual performance requirements of high unit thrust and low cruise fuel consumption of an advanced fighter aircraft under different working conditions. A variable cycle engine, which is based on a conventional turbofan engine and adds a new variable bypass ratio component, meets the flight requirements of low fuel consumption under subsonic speed and high unit thrust under supersonic speed by changing key thermal cycle parameters such as the bypass ratio of the engine, and has become a propulsive power form of modern fighters.

[0003] It can be found that the essential difference between the variable cycle engine and previous generations of engines and the core of obtaining superior performance lies in the ability to change the bypass ratio of the turbofan engine. The change in the bypass ratio is mainly realized by a new component of a duct ejector. The duct ejector is composed of two main components, a forward duct ejector and an aft duct ejector. The forward duct ejector increases the flow of the outer duct airflow of the engine by inducing a flow at the outlet of the first duct to mix the airflow of the outer duct of the fan, thereby realizing wide-range adjustment of the bypass ratio. In a conventional forward duct ejector, the airflow of the first duct and the airflow of the outer duct of the fan can only be mixed by inducing a low-intensity spanwise vortex, resulting in low mixing efficiency of the two airflows and difficulty in uniform mixing within the limited axial length of the engine. SUMMARY

[0004] To solve the problems in the prior art, the present application provides a lobed forward duct ejector with mixing enhancement function. The lobed forward duct ejector is connected to a first duct, an outer duct of a fan, an outer duct of an engine and a lobed ejector device in sequence along a circumference by lobes and guide vanes alternately, and the lobed ejector device is in communication with the first duct and the outer duct of the fan. When the airflow of the first duct and the airflow of the outer duct of the fan pass through the lobed ejector device, the low-speed airflow of the outer duct of the fan is efficiently induced, the induction ratio of the outer duct of the engine is effectively improved, the mixing is strengthened, the mixing distance is shortened, and the problem of uneven mixing of the airflow at the outlet of the outer duct of the engine is improved. To achieve the above purpose, the technical solution is as follows.

[0005] The present application provides a lobed forward duct ejector with mixing enhancement function. The lobed forward duct ejector comprises a first duct, an outer duct of a fan, an outer duct of an engine and a lobed ejector device.

[0006] The outlet of the first duct is connected to the wave peak inlet of the lobed ejector device,

[0007] The wave trough of the wave-lobe ejector device is in nested communication with the fan outer duct,

[0008] The outlet of the wave-lobe ejector device is in nested communication with the engine outer duct,

[0009] The wave-lobe ejector device comprises a wave lobe and a guide plate,

[0010] The wave lobe and the guide plate are alternately connected in sequence along the circumference.

[0011] Optionally, the wave lobe comprises a wave lobe peak plate, a wave lobe trough plate, and a wave lobe side plate.

[0012] The shape of the wave lobe peak plate comprises a rectangle, a rounded rectangle, and an arch.

[0013] The shape of the wave lobe trough plate comprises a semi-ellipse, a rounded rectangle, and an arch.

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

[0015] Optionally, the shape of the guide plate comprises a rectangle, a rounded rectangle, and an arch.

[0016] Optionally, the wave 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 wave lobe peak plate and the guide plate; and the airflow of the fan outer duct reaches the engine outer duct through the channel formed by the wave lobe trough plate.

[0018] Optionally, the wave lobe and the guide plate are alternately connected in sequence along the circumference, and the number of alternately connected pairs is not less than 2.

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

[0020]

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

[0022]

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

[0024]

[0025] Optionally, the mixing enhancement process of the ejector comprises:

[0026] The airflow of the first channel passes through the channel formed by the lobed peak plate and the guide plate to reach the engine outer channel, and a plurality of high-speed airflows are obtained;

[0027] The airflow of the fan outer channel passes through the channel formed by the lobed trough plate to reach the engine outer channel, and a plurality of low-speed airflows are obtained;

[0028] According to the plurality of high-speed airflows and the plurality of low-speed airflows, a large-scale streamwise vortex structure is induced at the outlet of the lobed ejector device, and the mixing enhancement function of the ejector is realized.

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

[0030] The above scheme forms a lobed ejector device by alternately connecting the lobes and the guide plates arranged along the circumference in sequence, and the lobed ejector device is in communication with the first channel and the fan outer channel respectively. After the airflow of the first channel and the airflow of the fan outer channel pass through the lobed ejector device, high-efficiency ejection is realized for the low-speed airflow of the fan outer channel, the ejection ratio of the engine outer channel can be effectively improved, the mixing is strengthened, the mixing distance is shortened, and the problem of uneven mixing of the airflow at the outlet of the engine outer channel is improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0032] Figure 1 is a three-dimensional structure schematic diagram of a lobed front channel ejector embodiment with mixing enhancement function of the present application;

[0033] Figure 2 is a front view schematic diagram of a lobed front channel ejector embodiment with mixing enhancement function of the present application;

[0034] Figure 3 is a three-dimensional structure schematic diagram of a lobed front channel ejector embodiment with mixing enhancement function of the present application;

[0035] Figure 4 is a schematic diagram of the lobed front channel ejector embodiment with mixing enhancement function of the present application along the circumferential arrangement of the lobed ejector device;

[0036] Figure 5This is a flowchart of the mixing and strengthening process of the ejector in an embodiment of the lobe-type front duct ejector with mixing and strengthening function of the present invention.

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

[0038] Explanation of the numbers in the diagram: First duct 1, fan outer duct 2, engine outer duct 3, lobe ejector device 4, lobe 41, guide plate 42, lobe crest plate 411, lobe trough plate 412, lobe side plate 413. Detailed Implementation

[0039] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0040] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0041] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0042] This embodiment uses a typical variable cycle engine front bypass ejector as an example. The airflow is decelerated after passing through the intake duct and then enters the engine where it is compressed by the fan. At the fan outlet, the airflow is split into two streams: one flowing towards the fan outer bypass duct 2 and the other towards the core drive fan. The airflow entering the core drive fan is split again at the outlet through a second stream section. A portion of the flow enters the first bypass duct 1, where it is ejected and mixed with the airflow from the fan outer bypass duct 2 within the front bypass ejector, before flowing towards the engine outer bypass duct 3.

[0043] like Figure 1 The diagram shows a three-dimensional structural schematic of an embodiment of the lobe-type front duct ejector with mixing enhancement function of the present invention, and as shown below. Figure 2 The diagram shown is a front view of an embodiment of the lobe-type front duct ejector with mixing enhancement function according to the present invention. The present invention provides a lobe-type front duct ejector with mixing enhancement function, which includes: 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 crest inlet of the lobe ejector 4.

[0045] The trough inlet of the beam ejector 4 is simultaneously nested with the fan outer duct 2.

[0046] The outlet of the beam ejector 4 is nested with the engine's outer bypass duct 3.

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

[0048] The wave lobe 41 and the guide plate 42 are arranged alternately along the circumference.

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

[0050] The shape of the wave crest plate 411 includes: rectangular, rounded rectangle and arched;

[0051] The shape of the wave trough plate 412 includes: semi-elliptical, rounded rectangle and arch;

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

[0053] Specifically, the shape of the deflector 402 includes: rectangular, rounded rectangle and arch.

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

[0055] Furthermore, the number of alternating connections of the lobe 41 and the guide plate 42 along the circumference is no less than two pairs.

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

[0057] Specifically, such as Figure 5 The flowchart shown is a flow chart of the mixing and strengthening process of the ejector in an embodiment of the lobe-type front duct ejector with mixing and strengthening function of the present invention. The mixing and strengthening process of the ejector includes:

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

[0059] The airflow of the fan bypass 2 reaches the engine bypass 3 through the channel formed by the wavelet trough plate 412, resulting in multiple low-speed airflows.

[0060] Based on the multiple high-speed airflows and the multiple low-speed airflows, a large-scale flow-oriented vortex system structure is induced at the outlet of the lobe ejector device 4, thereby realizing the mixing and strengthening function of the ejector.

[0061] Furthermore, by setting the guide plate 42, the airflow direction of the first duct 1 can be changed, and the wavelet ejector device 4 can increase the secondary flow, further improve the intensity of 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 evolution of the flow vortex system of the lobe-type front duct ejector with mixing enhancement function of the present invention is shown. Through simulation analysis, it can be seen that by adding the lobe ejector device 4, the contact area between the airflow of the first duct 1 and the airflow of the fan outer duct 2 is increased. 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, which forces the low-speed airflow of the fan outer duct 2 and the high-speed airflow of the first duct 1 to exchange momentum and energy, thereby achieving accelerated jet mixing with the least total pressure loss and 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 bypass duct 2 is as follows:

[0064]

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

[0066]

[0067] Specifically, the relationship between the crest width d of the lobe ejector 4 and the lobe trailing edge circumference S of the lobe ejector 4 is as follows:

[0068]

[0069] Furthermore, the method for calculating the lobe trailing edge circumference S is as shown in formula (1).

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

[0071] In the formula, S is the circumference of the lobe trailing edge; d is the arc length of the lobe crest plate, i.e., the width of the lobe crest plate; a is the arc length of the lobe trough plate, i.e., the width of the lobe trough plate; and c is the height of the lobe side plate.

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

[0073] It is understood that the present invention has been described through the above embodiments and should not be construed as limiting the implementation and scope of the present invention. Those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A lobed pre-diffuser ejector with mixing enhancement function, characterized in that, The ejector comprises a first duct, a fan outer duct, an engine outer duct and a lobed ejector device; The outlet of the first duct is connected with the peak inlet of the lobed ejector device, The valley inlet of the lobed ejector device is simultaneously in nested communication with the fan outer duct, The outlet of the lobed ejector device is in nested communication with the engine outer duct, The lobed ejector device comprises lobes and guide plates, The lobes and the guide plates are alternately connected in sequence along the circumferential arrangement; The lobe comprises a lobe peak plate, a lobe valley plate and a lobe side plate; The shape of the lobe peak plate comprises a rectangle, a rounded rectangle and an arch shape; The shape of the lobe valley plate comprises a semi-elliptical shape, a rounded rectangle and an arch shape; The lobe peak plate is connected with the upper end of the lobe side plate, and the lobe valley plate is connected with the lower end of the lobe side plate; The lobe peak plate is tangentially connected with the top of the guide plate; The relationship between the length L of the guide plate and the inlet height H of the fan outer duct is:

2. The lobed pre-diffuser ejector with mixing augmentation function of claim 1, wherein, The shape of the guide plate comprises a rectangle, a rounded rectangle and an arch shape.

3. The lobed pre-diffuser ejector with mixing augmentation function of claim 1, wherein, The airflow of the first duct reaches the engine outer duct through the channel formed by the lobe peak plate and the guide plate; and the airflow of the fan outer duct reaches the engine outer duct through the channel formed by the lobe valley plate.

4. The lobed pre-diffuser ejector with mixing augmentation function of claim 1, wherein, The number of the lobes and the guide plates alternately connected in sequence along the circumferential arrangement is not less than two pairs.

5. The lobed pre-diffuser ejector with mixing augmentation function of claim 1, wherein, The relationship between the lobe height h of the lobe and the inlet height H of the fan outer duct is:

6. The lobed pre-diffuser ejector with mixing augmentation function of claim 1, wherein, The relationship between the peak width d of the lobed ejector device and the lobe trailing edge circumference S of the lobed ejector device is 7. The lobed pre-diffuser mixer with mixing enhancement function of claim 3, wherein, The mixing enhancement process of the ejector comprises: The airflow of the first duct reaches the engine outer duct through the channel formed by the lobe peak plate and the guide plate, obtaining a plurality of high-speed airflows; The airflow of the fan outer duct reaches the engine outer duct through the channel formed by the lobe valley plate, obtaining a plurality of low-speed airflows; According to the plurality of high-speed airflows and the plurality of low-speed airflows, a large-scale streamwise vortex structure is induced at the outlet of the lobed ejector device, realizing the mixing enhancement function of the ejector.

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