CN111927645B

CN111927645B - Rear duct ejector with circumferentially covered valve body

Info

Publication number: CN111927645B
Application number: CN202010728066.8A
Authority: CN
Inventors: 董少静; 张益恺; 申秀丽; 廖智宇
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2021-07-02
Anticipated expiration: 2040-07-23
Also published as: CN111927645A

Abstract

The invention discloses a rear duct ejector with a circumferentially covered valve body, which comprises an outer casing, a pair of hydraulic actuating cylinders, a pair of hydraulic actuating rods, a pair of cranks, a pair of spherical hinge connecting rods, a circumferentially actuated valve body and the inner casing, wherein the pair of hydraulic actuating cylinders, the pair of hydraulic actuating rods, the pair of cranks and the pair of spherical hinge connecting rods are arranged in a central symmetry manner around the circle center of a plane where the outer casing is located. The technical scheme of the invention can adjust the area of the outer culvert outlet of the variable cycle engine; the valve body and the inner casing are mutually matched through a circumferential sliding groove, so that the opening and closing of an airflow channel can be realized through circumferential rotation; the valve body is a circumferentially closed one-piece valve body rather than a plurality of valve body pieces. The problem that synchronous movement of a plurality of valve body pieces is difficult to realize due to different stress conditions is solved.

Description

Rear duct ejector with circumferentially covered valve body

Technical Field

The invention belongs to the technical field of structural design of variable cycle engines, and particularly relates to a rear duct ejector with a circumferentially covered valve body.

Background

The variable cycle engine is also called a geometry adjustable engine, and refers to an engine capable of changing the bypass ratio of the engine under the action of adjusting the geometry of a component. Due to the adjustability of the bypass ratio of the engine, the geometrically adjustable engine has the advantages of high specific thrust of a turbojet engine and low oil consumption and low noise of a turbofan engine.

The variable cycle engine has two bypass ejectors, a front variable area bypass ejector (front bypass ejector) and a rear variable area bypass ejector (rear bypass ejector). The front bypass ejector is used for mixing two bypass airflows from the exhaust nozzle and the bypass nozzle, and the rear bypass ejector is used for mixing the bypass airflow and the low-pressure turbine outlet airflow.

The present design is mostly covered tightly for the synchronizing ring transmission valve body piece, and this kind of structure of covering is comparatively complicated, for example the edge between the initiative piece that utilizes the scale form to actuate and the gasket has the line contact of slant angle sealed mutually, and the gasket is the structure of cross-section "I" word, and this kind of seal structure is complicated, and the gas tightness is not very reliable when airflow channel closes.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides an area adjusting mechanism (namely a covering mechanism) different from the existing rear duct ejector, which is a covering mode of circumferential actuation of a valve body and can adjust the area of an outer duct outlet of a variable cycle engine. The specific technical scheme of the invention is as follows:

the rear duct ejector with the valve body circumferentially covered tightly is characterized by comprising an outer casing, a pair of hydraulic actuating cylinders, a pair of hydraulic actuating rods, a pair of cranks, a pair of spherical hinge connecting rods, a circumferentially actuated valve body and the inner casing, wherein the pair of hydraulic actuating cylinders, the pair of hydraulic actuating rods, the pair of cranks and the pair of spherical hinge connecting rods are arranged in a central symmetry manner around the circle center of a plane where the outer casing is located,

flange connecting structures are arranged at the front airflow channel and the rear airflow channel of the outer casing;

one end of each hydraulic actuating cylinder is pivotally mounted on a pair of shafts on the outer surface of the outer casing, and the other end of each hydraulic actuating cylinder is connected with the corresponding hydraulic actuating rod;

one ends of the pair of cranks are respectively connected with the pair of hydraulic actuating rods through plane hinges, and the other ends of the cranks are respectively arranged in the bearing bushes of the outer casing and can rotate around the central lines of the holes of the bearing bushes;

both ends of the pair of spherical hinge connecting rods are spherical hinges, one ends of the spherical hinge connecting rods are connected with the pair of cranks, and the other ends of the spherical hinge connecting rods are respectively connected with a pair of spherical hinge connecting ends on the valve body;

the valve body is of a split valve body structure and consists of two semi-annular valve bodies; the circumference of the end surface of the valve body is provided with a circumferential sliding rail which is matched with a circumferential sliding groove arranged on the circumference of the end surface of the inner casing, and the valve body can rotate freely; the valve body is uniformly and equidistantly provided with a plurality of valve body airflow channels, the part between every two valve body airflow channels is an active covering and sealing piece, the inner casing is uniformly and equidistantly provided with inner casing airflow channels matched with the active covering and sealing piece, the active covering and sealing piece and the inner casing airflow channels can be completely and tightly covered, the part between every two inner casing airflow channels is a fixed sealing piece, when the valve body rotates on the inner casing, the opening area of the inner casing airflow channels can be controlled by adjusting the rotating angle of the valve body, and the opening and closing of the inner casing airflow channels can be realized;

the outer circumferential edges of the front end face and the rear end face of the inner casing are respectively provided with lugs which are uniformly distributed and used for fixing the inner casing.

Further, the two semi-annular valve bodies of the valve body are connected by two pairs of shoulders, each pair of shoulders being fastened by five M5 bolts.

Furthermore, the outer casing, the pair of hydraulic actuating cylinders, the pair of hydraulic actuating rods, the pair of cranks and the pair of spherical hinge connecting rods are all made of high-temperature alloy steel GH 3128.

Further, the valve body and the inner casing are made of high-temperature alloy steel GH 536.

Furthermore, the valve body airflow channels are ten and are cylindrical rectangles, namely two opposite sides are straight line segments, the other two opposite sides are circular arc segments, and the size of the straight line segments is 154.5 mm; the inner diameter of the circular arc section is 397.5mm, the outer diameter is the same as the outer diameter of the valve body, 401.5mm, and the central angle is 18 degrees.

The invention has the beneficial effects that:

1. the rear duct ejector disclosed by the invention can be used for adjusting the area of the outlet of the outer duct of the variable cycle engine;

2. the valve body and the inner casing are matched with each other through the circumferential sliding groove, and the opening and closing of the airflow channel can be realized through circumferential rotation.

3. The valve body of the rear duct ejector designed by the invention is a whole valve body which is covered tightly in the circumferential direction, and is not covered tightly by a plurality of valve body pieces, so that the problem that synchronous movement of the valve body pieces is difficult to realize due to different stress conditions is solved. The invention has compact and reliable structure.

Drawings

In order to illustrate embodiments of the present invention or technical solutions in the prior art more clearly, the drawings which are needed in the embodiments will be briefly described below, so that the features and advantages of the present invention can be understood more clearly by referring to the drawings, which are schematic and should not be construed as limiting the present invention in any way, and for a person skilled in the art, other drawings can be obtained on the basis of these drawings without any inventive effort. Wherein:

FIG. 1 is an overall assembly view of a rear ducted eductor with a circumferentially closed valve body according to the present invention;

FIG. 2 is an isometric view of a rear duct injector of the present invention with a circumferentially closed valve body;

FIG. 3 is a right side view of a rear ducted eductor with a circumferentially closed valve body according to the present invention;

FIG. 4 is a front view of a rear bypass eductor with a circumferentially closed valve body according to the present invention;

FIG. 5 is a view of the outer casing of the rear duct ejector with a circumferentially covered valve body according to the present invention;

FIG. 6 is a view of the crank configuration of the rear bypass eductor with the valve body circumferentially closed in accordance with the present invention;

FIG. 7 is a view of the spherical hinge connecting rod structure of the rear duct ejector with the valve body circumferentially closed;

FIG. 8 is a block diagram of a rear ducted eductor valve with a circumferentially closed valve body according to the present invention;

fig. 9 is a block diagram of a rear ducted eductor inner cartridge with a circumferentially closed valve body according to the present invention.

FIG. 10 is a graph of angular velocity of rotation of the valve body versus time;

FIG. 11 is a schematic view of the closing and opening of the valve body during simulation;

FIG. 12 is a revolute pair diagram of a rigid valve body;

FIG. 13 is a revolute pair diagram of rigid and flexible valve bodies;

FIG. 14(a) is a stress cloud of a flexible valve body;

fig. 14(b) and 14(c) are partially enlarged views of fig. 14 (a).

The reference numbers illustrate:

1-an outer casing; 11-flange connection structure; 12-bearing bush; 13-axis; 2-a hydraulic actuator cylinder; 3-hydraulic actuating rod; 4-a crank; 5-a spherical hinge connecting rod; 6-valve body; 61-a ball hinge connection end; 62-shoulder; 63-actively covering and tightly sealing the sheet; 64-valve body airflow passage; 65-circumferential slide rails; 7-inner casing; 71-a lug; 72-fixing the sealing sheet; 73-inner casing airflow path.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

The design method adopted by the invention comprises the following steps: modeling, rigid body simulation and flexible simulation. As shown in fig. 1-4, a rear duct injector with a valve body covered tightly in the circumferential direction is characterized by comprising an outer casing 1, a pair of hydraulic actuating cylinders 2, a pair of hydraulic actuating rods 3, a pair of cranks 4 and a pair of spherical hinge connecting rods 5 which are arranged in a central symmetry manner about the circle center of a plane, a valve body 6 actuated in the circumferential direction and an inner casing 7,

as shown in fig. 1, flange connection structures 11 are arranged at the front and rear airflow channels of the outer casing 1;

one end of each hydraulic actuating cylinder 2 is pivotally mounted on a pair of shafts 13 on the outer surface of the outer casing 1, and the other end of each hydraulic actuating cylinder 2 is connected with a pair of hydraulic actuating rods 3 respectively, and the pair of hydraulic actuating cylinders 2 can drive the pair of hydraulic actuating rods 3 and simultaneously can rotate around the shafts 13 to avoid the nonlinear actuation of the pair of hydraulic actuating cylinders 2 and the pair of hydraulic actuating rods 3;

as shown in fig. 6-7, one end of each of the pair of cranks 4 is connected to the pair of hydraulic actuating rods 3 via a planar hinge, and the other end is mounted in the bearing bush 12 of the outer casing 1 and can rotate around the center line of the hole of the bearing bush 12;

both ends of the pair of spherical hinge connecting rods 5 are spherical hinges, one ends of the spherical hinge connecting rods are connected with the pair of cranks 4, and the other ends of the spherical hinge connecting rods are respectively connected with the pair of spherical hinge connecting ends 61 on the valve body 6;

as shown in fig. 8-9, the valve body 6 is a split valve body structure, and is composed of two semi-annular valve bodies; the circumference of the end surface of the valve body 6 is provided with a circumferential slide rail 65 which is matched with a circumferential slide groove arranged on the circumference of the end surface of the inner casing 7, and the valve body 6 can rotate freely; a plurality of valve body airflow channels 64 are uniformly and equidistantly arranged on the valve body 6, the part between every two valve body airflow channels 64 is an active covering and sealing piece 63, the inner casing 7 is uniformly and equidistantly provided with an inner casing airflow channel 73 matched with the active covering and sealing piece 63, the active covering and sealing piece 63 and the inner casing airflow channel 73 can be completely sealed and tightly covered, the part between every two inner casing airflow channels 73 is a fixed sealing piece 72, when the valve body 6 rotates on the inner casing 7, the opening area of the inner casing airflow channel 73 can be controlled by adjusting the rotating angle of the valve body 6, and the opening and closing of the inner casing airflow channel 73 can be realized;

the outer circumferential edges of the front and rear end faces of the inner case 7 are respectively provided with lugs 71 which are uniformly distributed and used for fixing the inner case 7.

The two semi-annular valve bodies of the valve body 6 are connected by two pairs of shoulders 62, each pair of shoulders 62 is fastened by five M5 bolts, the valve body 6 is assembled along the radial direction of the cylinder from both sides of the inner casing 7 when being installed, the threaded holes of the shoulders 62 are aligned, and then the bolts are installed.

The outer casing 1, the pair of hydraulic actuating cylinders 2, the pair of hydraulic actuating rods 3, the pair of cranks 4 and the pair of spherical hinge connecting rods 5 are all made of high-temperature alloy steel GH 3128.

The valve body 6 and the inner engine box 7 are made of high-temperature alloy steel GH 536.

The valve body airflow channel 64 is ten and is in a cylindrical surface rectangle, namely two opposite sides are straight line sections, the other two opposite sides are circular arc sections, and the size of the straight line sections is 154.5 mm; the inner diameter of the circular arc section is 397.5mm, the outer diameter is the same as the outer diameter of the valve body 6, 401.5mm, and the central angle is 18 degrees.

In order to facilitate understanding of the above technical solutions of the present invention, the above technical solutions of the present invention are described in detail through specific simulation experiments below.

UG is adopted in rigid modeling software, ANSYS is adopted in flexible valve finite element modeling software, ADAMS is adopted in simulation software, ten airflow channels are arranged on a valve body, the shape of the valve body is a cylindrical rectangle, namely two opposite sides are straight line sections, the other two opposite sides are circular arc sections, and the size of the straight line sections is 154.5 mm; the inner diameter of the circular arc section is 397.5mm, the outer diameter is the same as the outer diameter of the valve body 6, 401.5mm, and the central angle is 18 degrees.

Fig. 10 is a diagram of angular velocity of rotation of the valve body versus time. As can be seen from fig. 10, the initial position of the bypass ejector is in a closed state after 0 second, the angular velocity of the valve body of the bypass ejector is zero after 1 second, the angular acceleration is maximum, the area enclosed by the angular velocity and the time axis represents the rotation angle of the valve body, and it is shown that the rotation angle of the valve body is maximum at 1 second and the valve body is completely opened; the angular velocity of the valve body is zero again at the moment of 2 seconds, the angular acceleration is minimum, and the valve body is known to be completely closed at the moment, so that the standard of 1-second opening and 1-second closing meeting the design requirement is met. The core component in the invention is the valve body, so the simulation research mainly aims at the valve body. Fig. 11 is a schematic view of the closing and opening of the valve body in simulation.

Fig. 12 is a diagram of a rotating pair force of a rigid valve body, and it can be seen that the valve body reaches the maximum angle when t is 1s, the displacement is maximum, the acting force is minimum, and the minimum force is F169.2N; when the valve body moves to the closed state, t is 2s, the displacement is minimum, the acting force is maximum, and the maximum stress is F173.0N. The rotating pair stress of the valve body is the largest stress in all kinematic pairs.

Fig. 13 is a diagram of a revolute pair diagram of a rigid and flexible valve body, the solid line representing the rigid simulation result and the dotted line representing the flexible simulation result. It can be seen that the flexible valve body is stressed more, and the maximum stress is F ═ 182.4N, so the calculation by the flexible valve body in the subsequent strength analysis is more accurate. Fig. 14(a) is a stress cloud diagram of the flexible valve body, and fig. 14(b) and 14(c) are partial enlarged views of fig. 14(a), and it can be seen that the maximum stress position in the flexible valve body is the edge of the circumferential chute near the ball hinge.

Table 1 shows the 10 nodes of maximum equivalent stress under the driving conditions using the step function of the displacement of the hydraulic ram and the hydraulic rod. Node 14109 can be seen to correspond to that in fig. 14, indicating that the maximum stress location description of fig. 14 is correct.

TABLE 1 maximum equivalent stress node

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The rear duct ejector with the valve body circumferentially covered tightly is characterized by comprising an outer casing (1), a pair of hydraulic actuating cylinders (2), a pair of hydraulic actuating rods (3), a pair of cranks (4), a pair of spherical hinge connecting rods (5), a valve body (6) and an inner casing (7), wherein the pair of hydraulic actuating cylinders, the pair of hydraulic actuating rods, the pair of cranks and the pair of spherical hinge connecting rods are arranged in a central symmetry mode on the circle center of a plane where the hydraulic actuating cylinders are located,

the front airflow channel and the rear airflow channel of the outer casing (1) are both provided with flange connecting structures (11);

one end of each hydraulic actuating cylinder (2) is pivotally mounted on a pair of shafts (13) on the outer surface of the outer casing (1), the other end of each hydraulic actuating cylinder is connected with the corresponding pair of hydraulic actuating rods (3), and the pair of hydraulic actuating cylinders (2) can drive the pair of hydraulic actuating rods (3) and can rotate around the shafts (13) to avoid nonlinear actuation of the pair of hydraulic actuating cylinders (2) and the pair of hydraulic actuating rods (3);

one end of each crank (4) is connected with the corresponding hydraulic actuating rod (3) through a plane hinge, and the other end of each crank is installed in a bearing bush (12) of the outer casing (1) and can rotate around the center line of a hole of the bearing bush (12);

both ends of the pair of spherical hinge connecting rods (5) are spherical hinges, one ends of the spherical hinge connecting rods are connected with the pair of cranks (4), and the other ends of the spherical hinge connecting rods are respectively connected with a pair of spherical hinge connecting ends (61) on the valve body (6);

the valve body (6) is of a split valve body structure and is composed of two semi-annular valve bodies; a circumferential sliding rail (65) is arranged on the circumference of the end face of the valve body (6) and is matched with a circumferential sliding groove arranged on the circumference of the end face of the inner casing (7), and the valve body (6) can rotate freely; the valve body (6) is uniformly and equidistantly provided with a plurality of valve body airflow channels (64), the part between every two valve body airflow channels (64) is an active cover tight sealing sheet (63), the inner casing (7) is uniformly and equidistantly provided with inner casing airflow channels (73) matched with the active cover tight sealing sheet (63), the active cover tight sealing sheet (63) and the inner casing airflow channels (73) can be completely sealed and tightly covered, the part between every two inner casing airflow channels (73) is a fixed tight sealing sheet (72), when the valve body (6) rotates on the inner casing (7), the opening area of the inner casing airflow channels (73) can be controlled by adjusting the rotating angle of the valve body (6), and the opening and closing of the inner casing airflow channels (73) can be realized;

the outer circumferential edges of the front end face and the rear end face of the inner casing (7) are respectively provided with lugs (71) which are uniformly distributed and used for fixing the inner casing (7).

2. The rear bypass injector with the circumferentially covered valve body according to claim 1, characterized in that the two semi-annular valve bodies of the valve body (6) are connected by two pairs of shoulders (62), each pair of shoulders (62) being fastened by five M5 bolts.

3. The rear duct injector with the valve body circumferentially closed as claimed in claim 1, wherein the outer casing (1), the pair of hydraulic cylinders (2), the pair of hydraulic actuating rods (3), the pair of cranks (4) and the pair of ball-and-socket joints (5) are all made of high-temperature alloy steel GH 3128.

4. The rear duct injector with the circumferentially covered valve body as claimed in claim 1, characterized in that the valve body (6) and the inner casing (7) are made of high temperature alloy steel GH 536.

5. The rear duct injector with the valve body covered tightly in the circumferential direction is characterized in that ten valve body airflow channels (64) are formed in a cylindrical rectangular shape, namely two opposite sides are straight line sections, the other two opposite sides are circular arc sections, and the size of the straight line sections is 154.5 mm; the inner diameter of the circular arc section is 397.5mm, the outer diameter of the circular arc section is the same as the outer diameter of the valve body (6), the circular arc section is 401.5mm, and the central angle of the circular arc section is 18 degrees.