CN113982777B - Pneumatic thrust vectoring nozzle of two throats of linearization control - Google Patents

Abstract

The invention discloses a double-throat pneumatic vectoring nozzle capable of being controlled in a linear mode, which comprises: the spring-cam-valve mechanical device installed on the self-adaptive bypass, the valve of the self-adaptive bypass is always pulled upwards by elastic components such as a spring, and the valve of the self-adaptive bypass is always pressed downwards by a cam. When the radius of the cam changes, the valve moves upwards or downwards under the action of an elastic component such as a spring. The invention changes the actual opening degree of the self-adaptive bypass by the rotation of the cam and completes the conversion of the cam rotating at a constant speed and the vector angle changing linearly. The mechanical device has a simple structure, the whole spray pipe is slightly changed, the linear adjustment of the vector of the spray pipe can be completed, the adjustment of the flight attitude of the aircraft is facilitated, and the benefit is obvious.

Description

A linear controllable dual-throat aerodynamic vectoring nozzle

technical field

The invention belongs to the technical field of thrust vectoring aircraft engine nozzles, in particular to a linearly controllable dual-throat aerodynamic vectoring nozzle.

Background technique

With the development of science and technology and the improvement of actual needs, more and more thrust vectoring aeroengines will be used in future aircraft. The core of the thrust vectoring aeroengine to realize the thrust vectoring function is the thrust vectoring nozzle. The traditional mechanical thrust vectoring nozzle has complex structure, poor reliability and troublesome maintenance. Therefore, it is imminent to develop a thrust vectoring nozzle with simple structure, light weight and good maintenance performance.

At present, the fluid thrust vectoring nozzle has gradually become the research focus and research focus of various countries due to its simple structure and light weight, and will enter engineering applications in the near future. At the same time, how to adjust the vector nonlinear change caused by fluid unsteady phenomenon has become one of the new research directions in the field of thrust vectoring nozzles.

The throat offset pneumatic vectoring nozzle is a new type of fluid thrust vectoring nozzle that has emerged in recent years. It is favored by more and more people because of its simple structure, light weight, and good performance. Among them, the bypass passive aerodynamic vectoring nozzle is a kind of throat offset aerodynamic vectoring nozzle. It designs an adaptive pressure-regulated bypass, which adjusts the flow rate of the secondary flow through the size of the adaptive bypass opening, controls the degree of disturbance, and then adjusts the angle of the thrust vector to meet actual flight needs.

Due to the change of boundary conditions such as the opening or closing of the adaptive bypass valve, the instability and rupture of the vortex in the flow itself, and the flow phenomena related to turbulence, the unsteady phenomenon and the hysteresis and nonlinearity of the adjustment process of the double-throat aerodynamic vector nozzle Phenomenon. Therefore, it is of great engineering application value to develop a mechanical structure that can linearly adjust the vector generated by the double-throat aerodynamic vector nozzle with little change to the nozzle geometry.

Contents of the invention

Purpose of the invention: Aiming at the deficiencies in the prior art, the present invention proposes a linearly controllable double-throat pneumatic vectoring nozzle, which is a throat offset pneumatic vectoring nozzle comprising a spring-cam-valve adjustment mechanism. The mechanical structure is simple and reliable, and the linear adjustment of the thrust vector of the nozzle can be realized only by changing the opening of the nozzle valve.

In order to achieve the above technical purpose, the present invention will take the following technical solutions: a linearly controllable double-throat pneumatic vector nozzle of the present invention, including elastic components, cams, adjustable valves and double-throat pneumatic vector nozzles Tube body;

One end of the elastic component is fixed, and the other end is connected to the adjustable valve for restoring the position of the adjustable valve; the adjustable valve is embedded in the body of the double-throat pneumatic vectoring nozzle, and the cam is located at the One end is in contact with the adjustable valve, the position of the cam shaft is fixed, and the position of the other end of the adjustable valve in the adaptive bypass is adjusted through the uniform rotation of the cam to adjust the opening of the adaptive bypass to achieve Switching between a uniformly rotating cam and a linearly varying nozzle vector angle.

When the cam rotates at a constant speed, as the distance from the cam shaft center to the adjustable valve increases, the adjustable valve moves to the adaptive bypass, and the movement of the other end of the adjustable valve makes the opening of the adaptive bypass smaller. Driven by the adjustable valve, the elastic part is stretched or shortened.

Further, the adjustable valve is perpendicular to the adaptive bypass.

Further, the design method of the cam radius includes the following steps:

Step 1, the corresponding vector angle δ _i of the adaptive bypass under different openings x _i in the action process of the known adjustable valve, where i=1, 2, 3, ... n; the opening x _i represents the relative The opening is equal to the actual opening of the adaptive bypass channel divided by the total width of the adaptive bypass channel;

Fitting the data of the opening x _i and the vector angle δ _i , the relational expression δ=f(x) between the opening x and the vector angle δ can be obtained;

Step 2. Divide |δ _max | into T parts and arrange them into δ _t in order from small to large, where t=0, 1, 2, ..., T),

where δ ₀ =0;

Substituting δ _t into the relational expression δ=f(x) fitted in step 1, to obtain x _t corresponding to each δ _t ;

Step 3, let H _t =x _t *L;

Wherein, L is the width of the adaptive bypass channel, and H _t is the opening degree of the actual opening of the adaptive bypass;

Step 4, the radius of the cam is R _t , where t=0, 1, 2, ..., T, T+1, wherein R ₀ corresponds to the radius of the cam when the bypass channel is completely closed, and R _T+1 corresponds to the complete bypass channel The radius of the cam when it is opened, the cam rotates 180° to complete the process of the adaptive bypass from fully closed to fully open,

Define the height of the adjustable valve as P, and the distance between the cam shaft and the far side of the bypass channel as G;

Then: G＝R _t +P+H _t

Therefore, _Rt = _GPHt

=GPx _t *L

The cam radius corresponding to each opening x _t can be calculated;

When the bypass is completely closed, RT ₊₁ +P=G, RT ₊₁ can be calculated by this formula.

Furthermore, the function f(x) should satisfy the following two conditions: (1) the value of the opening x _t under the corresponding vector angle can be obtained; (2) the function f(x) should change monotonically within the domain of definition, and the The domain of definition refers to the valve opening corresponding to the vector angle from 0 to the maximum value.

Further, the transition of cams with different radii should be rounded and smooth, so the cam rotation angle should be as large as possible.

Furthermore, the mechanism for controlling the adjustable valve stroke is not limited to the spring-cam structure, and any structure that can adjust the valve stroke according to actual needs can be used, such as a worm gear transmission mechanism;

Further, the connecting end of the adjustable valve and the cam is pointed, and its working principle is similar to that of a pointed follower cam, which has a simple structure and can keep in contact with any complex cam profile to realize any movement of the follower (valve) obey the rules.

Further, the cam rotation angle should be as small as possible. On the one hand, the cam adjustment can respond quickly; on the other hand, it is conducive to the smooth transition of the cam under different radii.

A linear controllable double-throat aerodynamic vector nozzle of the present invention is suitable for the following situations:

(1) During the process of the bypass channel of the pneumatic vectoring nozzle from being completely closed to fully opened or from fully opened to fully closed, its vector angle increases or decreases monotonously;

(2) During the process of the bypass channel of the aerodynamic vectoring nozzle from completely closed to fully opened or from fully open to fully closed, its vector angle monotonically increases or monotonically decreases, and after reaching a certain extreme value, the extreme value is also The maximum or minimum value of the vector angle during the change of the bypass opening, and then the vector angle monotonously decreases or monotonically increases or oscillates;

Beneficial effects: the linearly controllable dual-throat aerodynamic vector nozzle provided by the present invention has the following advantages compared with the prior art:

(1) Under the premise of basically not changing the structure of the double-throat pneumatic vector nozzle, a mechanical structure for adjusting the opening of the valve is provided, so that when the valve is opened or closed, the vector angle of the nozzle changes linearly, which is convenient for equipment The aircraft with double-throat aerodynamic vector nozzles can adjust the flight attitude to increase its maneuverability;

(2) The linearization control method provided by the present invention is not limited to mechanisms such as springs, as long as it is a mechanical structure that can change the valve opening, such as a worm gear mechanism.

Description of drawings

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is a structural schematic diagram of the cam in the present invention.

Among them: 1. Elastic component, 2. Cam, 3. Adjustable valve, 4. Double-throat pneumatic vector nozzle body.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention but not to limit the scope of the present invention. It should be noted that these drawings are all simplified schematic diagrams, which are only used to schematically illustrate the basic structure of the present invention, so they only show the configurations related to the present invention.

As shown in Figure 1, a linearly controllable double-throat pneumatic vectoring nozzle of the present invention includes an elastic component 1, a cam 2, an adjustable valve 3 and a double-throat pneumatic vectoring nozzle body 4;

One end of the elastic member 1 is fixed, and the other end is connected to the adjustable valve 3 for restoring the position of the adjustable valve 3; the elastic member 1 in the present invention includes two springs arranged in parallel, including the first spring and the second spring. Two springs, one end of the first spring and the second spring are respectively fixed, the other end of the first spring is connected to the first connecting rod, the other end of the second spring is connected to the second connecting rod, the first connecting rod and the second connecting rod are located at the same On a straight line, and the adjustable valve 3 is located between the first connecting rod and the second connecting rod, and is connected with the first connecting rod and the second connecting rod.

One end of the adjustable valve 3 is in contact with the cam 2, and the position of the axis of the cam 2 remains unchanged. The other end of the adjustable valve 3 is located in the adaptive bypass of the double-throat pneumatic vector nozzle body 4. The adjustable Valve 3 is perpendicular to the adaptive bypass and is used to adjust the opening of the adaptive bypass.

When the cam 2 rotates at a constant speed, as the distance between the axis of the cam 2 and the adjustable valve 3 increases, the adjustable valve 3 moves to the adaptive bypass, so that the opening of the adaptive bypass becomes smaller, and the uniform rotation is realized. Switching between the cam 2 and the linearly changing vector angle, driven by the adjustable valve 3, the elastic member 1 is elongated.

As shown in Figure 2, the cam 2 is a key part of the present invention that can linearly control the double-throat aerodynamic vector nozzle. The cam 2 is an axisymmetric structure, the rotating shaft is located on the symmetrical axis, and the minimum distance from the rotating shaft to the edge of the cam 2 is R _min , the minimum distance from the rotating shaft to the edge of cam 2 is R _max ;

When the distance from the cam 2 shaft to the adjustable valve 3 is equal to the radius R _min of the cam 2, it corresponds to the case where the adaptive bypass is fully open; when the distance from the cam 2 shaft to the adjustable valve 3 is equal to the cam radius R _max , the corresponding When the adaptive bypass channel is completely closed, when the distance from the cam 2 shaft to the adjustable valve 3 is equal to the cam radius R _x , corresponding to the partially opened adaptive bypass channel, the cam radius R _min is greater than the cam radius R ₀ , and smaller than the cam radius R _max .

The design method of cam radius among the present invention, comprises the following steps:

Step 1. Knowing the vector angle δ _i of the adaptive bypass at different openings x _i during the action of the adjustable valve 3, where i=1, 2, 3, ... n;

The opening degree x _i represents the relative opening degree, which is equal to the actual opening degree of the adaptive bypass channel divided by the total width of the adaptive bypass channel;

Where x _i =0, 0.1, 0.2, ..., 1 are selected; when x _i =0, the valve is completely closed, and when x _i =1, the valve is fully opened;

Fitting the data of the opening degree x _i and the vector angle δ _i can obtain the relational expression δ=f(x) between the opening degree x and the vector angle δ; the relational expression may be a quadratic function.

Step 2. Divide |δ _max | into T parts, and arrange them into δ _t in order from small to large, where t=0, 1, 2, ..., T, and the |δ _max | refers to the maximum value in δ _i ;

where δ ₀ =0;

Substitute δ _t into the relational expression δ=f(x) fitted in step 1 to obtain the x t corresponding to each δ _t . If the value of x _t obtained is greater than 1, it is an error value; if two values of _{x t are} obtained , and are all within the value range of 0-1, a more appropriate value can be selected according to the actual situation;

Therefore, the function f(x) should meet the following two conditions: (1) the value of the opening x _t under the corresponding vector angle can be obtained; (2) the function f(x) should change monotonically in the domain of definition, and the domain of definition is Refers to the valve opening corresponding to the vector angle from 0 to the maximum value.

Step 3, let H _t =x _t *L;

Wherein, L is the width of the adaptive bypass channel, and H is the absolute value of the actual opening of the adaptive bypass;

Step 4, the radius of cam 2 is R _t , where t=0, 1, 2, ..., T, T+1, where R ₀ corresponds to the radius of cam 2 when the bypass is completely closed, and R _T+1 corresponds to the bypass The radius of cam 2 when the channel is fully opened, and cam 2 rotates 180° to complete the process of adaptive bypass from fully closed to fully open,

Define the height of the adjustable valve 3 as P, and the distance between the rotating shaft of the cam 2 and the far side of the bypass channel as G.

Then: G＝R _t +P+H _t

Therefore, _Rt = _GPHt

=GPx _t *L

The radius of cam 2 corresponding to each opening x _t can be calculated.

When the bypass is fully closed, R _{T + 1} + P = G, when the bypass is fully open, R ₀ + P + L = G, when the valve is partially opened, R _t corresponds to the value of the adaptive bypass The actual opening H _t , then R _t +P+H _t =G. At this time, the angle α _t between R ₀ and R _t is x _t *180°;

The normal working state of the present invention is divided into two kinds: the vector open state and the vector closed state, and the working state is switched by the rotation direction of the cam 2 . Taking the vector opening as an example, when the cam 2 rotates counterclockwise at a constant speed, the radius of the cam 2 decreases at the contact point between the valve and the cam 2, and under the action of the spring and other elastic components 1, the valve moves away from the passage, and the valve automatically To adapt to the gradual opening of the bypass, the flow rate of the secondary flow gradually increases, the injected airflow exerts a vertical force on the main flow, the main flow is disturbed and flows along the side wall of the expanding and converging section at the front of the secondary throat, and through the action of the concave cavity The airflow deflection effect amplifies the ejection, and finally generates a head-up or head-down moment. The nozzle has a corresponding vector angle under different adaptive bypass openings, and the corresponding valve opening when the vector angle changes linearly is converted into the radius of the cam 2. Under the action of the uniform rotation of the cam 2, the valve follows the fitting formula Regular action, the opening of the adaptive bypass changes, so as to realize the linear change of the vector angle.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

The double-throat aerodynamic vectoring nozzle is designed for the typical configuration design under the pressure ratio NPR=4.

The table shows the variation law of the nozzle vector angle with the valve opening

Valve opening x_i 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 vector angle 0 8.04 18.61 19.72 20.63 21.45 22.3 23.1 23.79 23.9 18.93

Step 1, according to the data in Table 1, the logarithmic function is selected for fitting, and y=7.5142ln(x)+26.419 is obtained.

Step 2: Divide |δ _imax |=23.9 evenly into 10 parts, and calculate the corresponding valve opening x _t .

Step 3, use the formula H _t =x _t *L to obtain the adaptive bypass channel width H _t of the valve under the response opening.

Step 4. Assuming that the radius R ₀ of the cam 2 is 2mm when the bypass channel is completely closed, and the rotation angle of the cam 2 is 180° when the valve is fully closed to fully open, calculate the radius and rotation angle of the cam 2 at the corresponding opening degree , as shown in the table below.

As described in the above steps, the design of the cam profile is completed.

Claims (2)

1. A double-throat pneumatic vectoring nozzle capable of being controlled linearly is characterized by comprising an elastic component, a cam, an adjustable valve and a double-throat pneumatic vectoring nozzle body;

one end of the elastic component is fixed, and the other end of the elastic component is connected with the adjustable valve and used for restoring the position of the adjustable valve;

the adjustable valve is embedded into the double-throat pneumatic vectoring nozzle body, the cam is positioned at one end of the adjustable valve and is in contact with the adjustable valve, the position of the axis of the cam is fixed, the position of the other end of the adjustable valve in the adaptive bypass is adjusted through the uniform rotation of the cam so as to adjust the opening of the adaptive bypass, and the switching between the cam rotating at a uniform speed and a linearly-changed nozzle vector angle is realized; the adjustable valve is vertical to the self-adaptive bypass;

the method for designing the cam radius comprises the following steps:

step 1, self-adaptive bypass is controlled to different opening degrees x in the action process of the known adjustable valve _i The corresponding vector angle delta _i Wherein i =1, 2, 3, \8230:; opening x _i Representing a relative opening, equal to the actual opening of the adaptive bypass channel divided by the total width of the adaptive bypass channel;

to the opening degree x _i Sum vector angle delta _i Fitting the data to obtain a relational expression delta = f (x) of the opening x and the vector angle delta;

step 2, converting the absolute value delta _max The | is divided into T parts and arranged into delta from small to large _t Where T =0, 1, 2, \ 8230;, T),

wherein delta ₀ ＝0；

Will delta _t Substituting into the relation delta = f (x) fitted in step 1 to obtain each delta _t Corresponding to x _t ；

Step 3, letting H _t ＝x _t *L；

Wherein L is the width of the adaptive bypass channel, H _t Opening for actual opening of the adaptive bypass;

step 4, the radius of the cam is R _t Wherein T =0, 1, 2, \ 8230, T, T +1, wherein R ₀ Corresponding to the radius of the cam when the bypass channel is completely closed, R _T+1 The cam rotates 180 degrees corresponding to the radius of the cam when the bypass channel is fully opened, the process of self-adaptive bypass from full closing to full opening is completed,

defining the height of an adjustable valve as P and the distance between a cam rotating shaft and the far side of the bypass channel as G;

then: g = R _t +P+H _t

Therefore, R _t ＝G-P-H _t

＝G-P-x _t *L

Can calculate the corresponding opening x _t A corresponding cam radius;

when the bypass is completely closed, R _T+1 + P = G, from which R can be calculated _T+1 。

2. The linearizable control dual throat aerodynamic vectoring nozzle of claim 1, wherein the function f (x) satisfies the following two conditions: (1) Can obtain the opening x under the corresponding vector angle _t A value of (d); (2) The function f (x) should be monotonically varying within a defined domain, which refers to the corresponding valve opening between a vector angle of 0 and a maximum value.

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