Parallel twin-venturi thrust vectoring nozzle and design method thereof

Abstract

The application discloses a parallel double-throat thrust vector nozzle and a design method thereof, which comprises a nozzle main wall, a nozzle side wall and a control device; an internal space formed by the nozzle main wall and the nozzle side wall forms a flow channel, and a cross section of the flow channel is rectangular; the nozzle main wall is composed of a nozzle straight section, a nozzle contraction section and a nozzle expansion section, and the three are integrally designed and smoothly connected in shape; one side of the nozzle straight section is an inlet cross section of the nozzle, and one side of the nozzle expansion section is an outlet cross section of the nozzle; the control device comprises a straightening piece and a deflection control piece, the straightening piece is fixed in a groove arranged on the nozzle side wall, and the deflection control piece is fixed on the nozzle side wall through a rotating shaft. The parallel double-throat vector nozzle is simple in structure and can ensure the establishment of a flow field; the straightening piece can ensure the stability of upstream airflow, linear vector control of a wake flow can be realized through linear deflection of the deflection control piece, and the vector control effect will not be attenuated under a high pressure drop ratio.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of supersonic thrust vectoring nozzle, and particularly relates to a parallel double-throat thrust vectoring nozzle and a design method thereof. BACKGROUND

[0002] With the rapid development of aircraft, thrust vector control will become the standard configuration of aircraft in the future. As the core of thrust vector control technology, thrust vectoring nozzle can greatly improve the overall performance of the aircraft, expand the flight envelope, fully develop the potential of the aircraft, such as the maneuverability and agility of the aircraft in the overspeed state at high angles of attack, reduce the size of the rudder surface or even replace the horizontal tail and vertical tail, enhance the stealth performance of the aircraft, and reduce the weight of the aircraft, and greatly shorten the take-off and landing sliding distance of the aircraft, such as vertical take-off and landing.

[0003] At present, thrust vectoring nozzles are mainly divided into mechanical and aerodynamic types. The traditional mechanical thrust vectoring nozzle has a complex structure, is heavy, and is difficult to maintain. The vector control effect of most aerodynamic thrust vectoring nozzles is nonlinear, often accompanied by hysteresis, and the vector control efficiency is low under high NPR (NPR>10) conditions. Therefore, there is an urgent need to propose a new type of thrust vectoring nozzle which can be linearly controlled, has a simple structure, and can still achieve control effect under high NPR conditions. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a parallel double-throat thrust vectoring nozzle and a design method thereof. Based on the Laval nozzle profile, a deflection control piece arranged at a special position is obtained through transformation. The control piece and the upper and lower wall surfaces of the nozzle form a parallel double-throat system, respectively. By linearly actuating the control piece to disturb the main flow, the deflection of the airflow is realized, and then the linear vector control is realized. The needs of the aircraft for thrust vector control can be met.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The parallel double-throat thrust vectoring nozzle of the present application comprises a nozzle main wall, a nozzle side wall and a control device. The internal space formed by the nozzle main wall and the nozzle side wall forms a flow passage, and the cross section of the flow passage is rectangular.

[0007] The nozzle main wall is composed of a nozzle straight section, a nozzle converging section and a nozzle diverging section, and the three are integrally designed and smoothly connected in profile. One side of the nozzle straight section is the inlet cross section of the nozzle, and one side of the nozzle diverging section is the outlet cross section of the nozzle.

[0008] The control device comprises a fairing and a deflection control piece. The fairing is fixed in the groove provided on the nozzle side wall. The deflection control piece is fixed on the nozzle side wall through a rotating shaft.

[0009] Further, the rectification piece gradually widens, the convergent section of the nozzle and the rectification piece form gradually convergent flow channels on both sides of the control device; the deflection control piece gradually narrows, the divergent section of the nozzle and the deflection control piece form gradually divergent flow channels on both sides of the control device, thus the control device and the convergent section and the divergent section of the nozzle form a convergent-divergent nozzle, and the flow channels on both sides of the control device are respectively provided with a throat to form parallel double-throats.

[0010] Further, the throat represents the narrowest position of the flow channel.

[0011] Further, the upper and lower surfaces of the rectification piece and the deflection control piece are both smooth curved surfaces.

[0012] Further, the windward end of the rectification piece is a sharp corner, and the leeward end is a circular arc.

[0013] Further, the windward end of the deflection control piece is a circular arc, and the leeward end is a sharp corner, and the windward end of the deflection control piece completely matches the leeward end of the rectification piece.

[0014] Further, the divergent section of the nozzle has two expansions along the flow direction, the first expansion part is called a base section, the second expansion part is called a re-expansion section, and the transition part between the first expansion and the second expansion is called a connection section.

[0015] Further, the divergent section of the nozzle is composed of the base section, the connection section and the re-expansion section, and the three sections are smoothly connected.

[0016] Further, the deflection control piece is integrally formed with the rotating shaft.

[0017] In the present application, the airflow enters the flow channel from the inlet section of the nozzle, is divided into two airflows by the rectification piece, and is gradually accelerated in the convergent flow channels formed by the convergent section of the nozzle and the rectification piece, reaches the sound speed at the throat position, and is gradually accelerated to supersonic speed in the divergent flow channels formed by the divergent section of the nozzle and the deflection control piece; after passing through the deflection control piece, the two airflows form one airflow, the rotating shaft drives the deflection of the deflection control piece, and the deflection of the outflowing airflow is realized.

[0018] The present application provides a design method of a parallel double-throat thrust vectoring nozzle, and the steps are as follows:

[0019] Step 1): According to the design requirements, the height H of the original convergent-divergent nozzle throat, the outlet height, the overall divergent length of the nozzle and the required vector deflection angle α are determined. th

[0020] ​Step 2): Determine the overall profile of the control device according to the vector deflection angle a: draw a straight line with an angle of a with the horizontal position, and tangent to the expansion part of the original convergent-divergent nozzle selected in step 1, the straight line intersects the contraction part of the original convergent-divergent nozzle at a point, and intercepts the original convergent-divergent nozzle profile between the tangent point and the intersection point, and symmetrically along the straight line;

[0021] Step 3): Set the minimum distance h between the divergent section of the nozzle and the control device: h = H H th , denoted as point A on the control device and point B on the divergent section of the nozzle, the distance between AB is h;

[0022] Step 4): Replace the profile near point A on the control device in step 3 with a small circular arc to ensure that the minimum distance h remains unchanged when the control device rotates around the rotation axis, specifically: take the rotation axis as the center, and take the distance from the center to point A as the radius to make a circle, and smoothly connect with the profile of the control device;

[0023] Step 5): Cut the profile obtained in step 2 along the circle made in step 4 into two parts, the part near the inlet cross section of the nozzle is the straightener, and the other part near the outlet cross section of the nozzle is the deflection control piece, to ensure the stability of the upstream airflow when the control device rotates around the rotation axis;

[0024] Step 6): Set the expansion angle β of the base section of the divergent section of the nozzle and the vector deflection angle a to have the following relationship: β = a + 13°, and set the expansion angle γ of the re-expansion section and the vector deflection angle a to have the following relationship: γ = β + 20°, the base section and the re-expansion section are smoothly connected by the connecting section, and the three sections are combined to obtain the divergent section of the nozzle;

[0025] Step 7): Set the height of the inlet cross section of the nozzle and the height of the constant section of the nozzle to be greater than the height H th of the throat of the original convergent-divergent nozzle in step 1, to obtain the constant section of the nozzle;

[0026] Step 8): Set the contraction limit of the nozzle contraction section at the throat position, and smoothly connect the nozzle contraction section with the constant section of the nozzle and the divergent section of the nozzle respectively;

[0027] Step 9): Combine the constant section of the nozzle obtained in step 7, the nozzle contraction section set in step 8, and the divergent section of the nozzle obtained in step 6 to form a new convergent-divergent nozzle as the main wall of the nozzle;

[0028] Step 10): Set the length of the side wall of the nozzle to be greater than or equal to the distance from the inlet cross section of the nozzle to the outlet cross section of the nozzle, to obtain the side wall of the nozzle;

[0029] Step 11): the nozzle side wall obtained in step 10), the nozzle main wall obtained in step 9) and the rectification sheet, the deflection control sheet obtained in step 5) are combined to form a complete vector nozzle.

[0030] Advantages of the present application:

[0031] The parallel double-throat vector nozzle of the present application has simple structure, the nozzle main wall is of the first contraction-then expansion type, which ensures the establishment of the flow field; the control device is composed of a rectification sheet and a deflection control sheet, the rectification sheet can ensure the stability of the upstream airflow, the linear deflection of the deflection control sheet can realize the linear vector control of the wake flow, and the vector control effect will not decay under high pressure drop ratio (NPR>10). BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Fig. 1 is a three-dimensional structural schematic diagram of the vector nozzle of the present application;

[0033] Figure 2 Fig. 2 is a two-dimensional structural schematic diagram of the deflection control sheet in the non-deflection state of the vector nozzle of the present application;

[0034] Figure 3 Fig. 3 is a two-dimensional structural schematic diagram of the deflection control sheet in the deflection state of the vector nozzle of the present application;

[0035] Figure 4 Fig. 4 is a local schematic diagram of the vector nozzle of the present application;

[0036] Figure 5 Fig. 5 is a vector control effect simulation diagram of the vector nozzle of the present application. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of those skilled in the art, the present application will be further described below in conjunction with the embodiments and the drawings, and the contents mentioned in the embodiments are not limitations of the present application.

[0038] Reference Figures 1 to 3 As shown in the figure, the parallel double-throat thrust vector nozzle of the present application comprises a nozzle main wall, a nozzle side wall and a control device; the internal space formed by the nozzle main wall and the nozzle side wall forms a flow passage, and the cross section of the flow passage is rectangular;

[0039] The nozzle main wall is composed of a nozzle straight section 2, a nozzle contraction section 3 and a nozzle expansion section 7, and the three are integrally designed and smoothly connected in shape; one side of the nozzle straight section 2 is the inlet cross section 1 of the nozzle, and one side of the nozzle expansion section 7 is the outlet cross section 8 of the nozzle;

[0040] The control device comprises a rectification sheet 4 and a deflection control sheet 6, the rectification sheet 4 is fixed in the groove provided on the nozzle side wall; the deflection control sheet 6 is fixed on the nozzle side wall through a rotating shaft 5.

[0041] Wherein, the straightener 4 is gradually widened, the convergent section 3 and the straightener 4 form gradually convergent tendency of the flow channel on both sides of the control device; the deflection control piece 6 is gradually narrowed, the divergent section 7 and the deflection control piece 6 form gradually divergent tendency of the flow channel on both sides of the control device, thus the control device and the convergent-divergent nozzle formed by the convergent section 3 and the divergent section 7 form a convergent-divergent nozzle, and the flow channel on both sides of the control device is respectively provided with a throat 9 to form parallel double-throat.

[0042] Specifically, the throat 9 represents the narrowest position of the flow channel.

[0043] Specifically, the upper and lower surfaces of the straightener 4 and the deflection control piece 6 are smooth curved surfaces.

[0044] Specifically, the windward end (front end) of the straightener 4 is a sharp corner, and the leeward end (rear end) is a circular arc.

[0045] Specifically, the windward end of the deflection control piece 6 is a circular arc, and the leeward end is a sharp corner, and the windward end completely matches the leeward end of the straightener 4.

[0046] Specifically, the divergent section 7 has two expansions along the flow direction, the first expansion part is called a base section, the second expansion part is called a re-expansion section, and the transition part between the first expansion and the second expansion is called a connection section.

[0047] Specifically, the divergent section 7 is composed of the base section, the connection section and the re-expansion section, and the three sections are smoothly connected.

[0048] Specifically, the deflection control piece 6 is integrally formed with the rotating shaft 5.

[0049] In the present application, the airflow enters the flow channel from the inlet section 1 of the nozzle, is divided into two airflows by the straightener 4, and is gradually accelerated in the convergent flow channel formed by the convergent section 3 and the straightener 4, reaches the sound speed at the throat 9, and is gradually accelerated to supersonic speed in the divergent flow channel formed by the divergent section 7 and the deflection control piece 6; after passing through the deflection control piece 6, the two airflows form one airflow, the rotating shaft 5 rotates to drive the deflection of the deflection control piece 6, and the deflection of the outflowing airflow is realized.

[0050] The present application provides a design method of parallel double-throat thrust vectoring nozzle, and the steps are as follows:

[0051] Step 1): According to the design requirements, the height H of the original convergent-divergent nozzle throat, the outlet height, the overall divergent length of the nozzle and the required vector deflection angle α are determined. th

[0052] ​Step 2): Determine the overall profile of the control device according to the vector deflection angle a: draw a straight line with an angle of a with the horizontal position, and tangent to the expansion part of the original convergent-divergent nozzle selected in step 1, the straight line intersects the contraction part of the original convergent-divergent nozzle at a point, and intercepts the original convergent-divergent nozzle profile between the tangent point and the intersection point, and symmetrically along the straight line;

[0053] Step 3): Set the minimum distance h between the divergent section of the nozzle and the control device: h = H H th , denoted as point A on the control device and point B on the divergent section of the nozzle, the distance between AB is h;

[0054] Step 4): Replace the profile near point A on the control device in step 3) with a small circular arc to ensure that the minimum distance h remains unchanged when the control device rotates around the rotation axis, specifically: take the rotation axis as the center, and take the distance from the center to point A as the radius to make a circle, and smoothly connect with the profile of the control device;

[0055] Step 5): Cut the profile obtained in step 2) along the circle made in step 4) into two parts, the part near the inlet cross section of the nozzle is the straightener, and the other part near the outlet cross section of the nozzle is the deflection control piece, to ensure that the upstream airflow is stable when the control device rotates around the rotation axis;

[0056] Step 6): Set the expansion angle β of the base section of the divergent section of the nozzle and the vector deflection angle a to have the following relationship: β = a + 13°, and set the expansion angle γ of the re-expansion section and the vector deflection angle a to have the following relationship: γ = β + 20°, the base section and the re-expansion section are smoothly connected by the connecting section, and the three sections are combined to obtain the divergent section of the nozzle;

[0057] Step 7): Set the height of the inlet cross section of the nozzle and the height of the straight section of the nozzle to be greater than the height H th of the throat of the original convergent-divergent nozzle in step 1, to obtain the straight section of the nozzle;

[0058] Step 8): Set the contraction limit of the nozzle contraction section at the throat position, and smoothly connect the nozzle contraction section with the straight section of the nozzle and the divergent section of the nozzle respectively;

[0059] Step 9): Combine the straight section of the nozzle obtained in step 7), the nozzle contraction section set in step 8), and the divergent section of the nozzle obtained in step 6) to form a new convergent-divergent nozzle as the main wall of the nozzle;

[0060] Step 10): Set the length of the side wall of the nozzle to be greater than or equal to the distance from the inlet cross section of the nozzle to the outlet cross section of the nozzle, to obtain the side wall of the nozzle;

[0061] Step 11): The nozzle side wall obtained in step 10), the nozzle main wall obtained in step 9) and the rectifier and deflection control piece obtained in step 5) are combined to form a complete vector nozzle.

[0062] In the example, for a certain requirement, the designed vector nozzle can realize a vector deflection angle of ±15°. Referring to Fig. 1, the specific steps are as follows: Figure 4

[0063] 1) A Ma2.5 "first contraction-then expansion" nozzle profile is selected, the nozzle H t = 22.19 mm, the nozzle outlet height is 150 mm;

[0064] 2) A straight line with an angle of 15° with the horizontal direction is tangent to the intersection point X of the Ma2.5 first contraction-then expansion nozzle expansion section profile and the intersection point Y of the Ma2.5 first contraction-then expansion nozzle contraction section profile, the profile curve XY is the one-side profile of the control device, and the complete profile composed by the symmetry along the straight line XY is the two-dimensional section of the control device;

[0065] 3) The point A of the two-dimensional section of the control device obtained in step 2) is vertically connected with XY, and the intersection point is the position of the rotating shaft 5. A circular arc is drawn with the intersection point as the center and the distance from the intersection point to point A as the radius, so as to divide the combined two-dimensional section into a rectifier and a deflection control piece;

[0066] 4) The circular arc obtained in step 3) is used to replace the profile near the point A and the symmetric other side, and is smoothly connected with the rear profile of the deflection control piece;

[0067] 5) The throat position is determined according to the formula h H th = 11.095 mm;

[0068] 6) The profile positions of the base section and the re-expansion section of the nozzle expansion section are determined according to the formula β = α + 13° = 25° and γ = β + 20° = 48°, the base section and the re-expansion section are smoothly connected by the connecting section, and the nozzle expansion section is obtained;

[0069] 7) The nozzle inlet height and the nozzle straight section height are set to 40 mm, and the nozzle straight section is obtained;

[0070] 8) The nozzle contraction section is gradually contracted to the throat position, and the nozzle contraction section is smoothly connected with the nozzle straight section and the nozzle expansion section;

[0071] 9) The nozzle straight section obtained in step 7), the nozzle contraction section set in step 8) and the nozzle expansion section obtained in step 6) are combined to obtain a nozzle main wall;

[0072] 10) The length of the nozzle side wall is set to 200 mm, and the nozzle side wall is obtained;​

[0073] 11) The nozzle main wall obtained in step 9), the nozzle side wall obtained in step 9), and the rectification sheet and deflection control sheet obtained in step 3) are combined to form a complete vectoring nozzle.

[0074] Figure 5 The linear deflection effect of the deflection control sheet on the wake flow is illustrated when the nozzle pressure ratio is 15, and the feasibility of the vectoring control technology of the present application is verified.

[0075] The present application has many specific application approaches, and the above description is only the preferred embodiment of the present application. It should be pointed out that for ordinary skilled persons in the technical field, several improvements can be made without departing from the principles of the present application, and these improvements should also be considered as the protection scope of the present application.

Claims

1. A parallel twin-duct thrust vectoring nozzle, characterized by, Comprise: The main wall of the nozzle, the nozzle side wall and control device; The internal space formed by the main wall of the nozzle and the nozzle side wall forms a flow passage, and the cross section of the flow passage is rectangular; The main wall of the nozzle is composed of a nozzle constant section (2), a nozzle contraction section (3) and a nozzle expansion section (7), and the three are integrally designed and smoothly connected; one side of the nozzle constant section (2) is the inlet cross section (1) of the nozzle, and one side of the nozzle expansion section (7) is the outlet cross section (8) of the nozzle; The control device includes a rectifier blade (4) and a deflection control blade (6), the rectifier blade (4) is fixed in the groove provided on the nozzle side wall; the deflection control blade (6) is fixed on the nozzle side wall through a rotating shaft (5); The rectifier blade (4) gradually widens, the nozzle contraction section (3) and the rectifier blade (4) form a gradually contracting trend of the flow passage on both sides of the control device; the deflection control blade (6) gradually narrows, the nozzle expansion section (7) and the deflection control blade (6) form a gradually expanding trend of the flow passage on both sides of the control device, so that the control device, the nozzle contraction section (3) and the nozzle expansion section (7) form a converging-diverging nozzle, and the flow passage on both sides of the control device is provided with a throat (9) to form parallel double throats; The upper and lower surfaces of the rectifier blade (4) and the deflection control blade (6) are smooth curved surfaces; The windward end of the rectifier blade (4) is a sharp corner, and the leeward end is a circular arc; The windward end of the deflection control blade (6) is a circular arc, and the leeward end is a sharp corner, and the windward end thereof is completely attached to the leeward end of the rectifier blade (4); The nozzle expansion section (7) has two expansions along the flow direction, the first expansion part is called the base section, the second expansion part is called the re-expansion section, and the transition part between the first and second expansions is called the connection section.

2. The parallel twin-lobed thrust vectoring nozzle of claim 1, wherein, The throat (9) represents the narrowest position of the flow passage.

3. The parallel twin-lobed thrust vectoring nozzle of claim 1, wherein, The nozzle expansion section (7) is composed of the base section, the connection section and the re-expansion section, and the three sections are smoothly connected.

4. The parallel twin-lobed thrust vectoring nozzle of claim 1, wherein, The deflection control blade (6) is integrally formed with the rotating shaft (5).

5. A method of designing a parallel twin-lobed thrust vectoring nozzle, characterized in that, The steps are as follows: Step 1): Determine the original height H of the convergent-divergent nozzle throat according to the design requirements th , exit height, overall divergent length of the nozzle, and the required vector deflection angle a; Step 2): Determine the overall profile of the control device according to the vector deflection angle α: draw a straight line with an angle of α with the horizontal position, and make the straight line tangent to the expansion part of the original converging-diverging nozzle selected in step 1), and the straight line intersects with the contraction part of the original converging-diverging nozzle at a point, and cut the profile of the original converging-diverging nozzle between the tangent point and the intersection point, and symmetrically along the straight line; Step 3): Set the minimum distance h between the nozzle divergent section and the control device: h = h H th , denoted as point A on the control device and point B on the nozzle divergent section, with a distance h between A and B; Step 4): Replace the profile near point A of the control device in step 3) with a small circular arc to ensure that the minimum distance h of the control device is fixed when the control device is controlled around the rotating shaft, specifically: taking the rotating shaft as the center, and taking the distance from the center to point A as the radius to make a circle, and smoothly connecting the circle with the profile of the control device; Step 5): Cut the profile obtained in step 2) along the circle made in step 4) into two parts, the part near the inlet cross section of the nozzle is the rectifier blade, and the other part near the outlet cross section of the nozzle is the deflection control blade, to ensure that the upstream airflow is stable when the control device is controlled around the rotating shaft. Step 6): Set the expansion angle β of the base section of the nozzle expansion section and the vector deflection angle α to have the following relationship: β = α + 13°, and the expansion angle γ of the re-expansion section and the vector deflection angle α to have the following relationship: γ = β + 20°, the base section and the re-expansion section are smoothly connected by a connecting section, and the three sections are combined to obtain the nozzle expansion section; Step 7): Set the height of the inlet section of the nozzle and the height of the nozzle constant section to be greater than the height H of the original convergent-divergent nozzle throat in step 1) th , to obtain a nozzle constant section; Step 8): Set the nozzle contraction section to reach the contraction limit at the throat position, and the nozzle contraction section is smoothly connected with the nozzle straight section and the nozzle expansion section respectively; Step 9): Combine the nozzle straight section obtained in step 7), the nozzle contraction section set in step 8), and the nozzle expansion section obtained in step 6) to constitute a new convergent-divergent nozzle as a nozzle main wall; Step 10): Set the length of the nozzle side wall to be greater than or equal to the distance from the nozzle inlet section to the nozzle outlet section to obtain the nozzle side wall; Step 11): Combine the nozzle side wall obtained in step 10), the nozzle main wall obtained in step 9), and the fairing and deflection control piece obtained in step 5) to form a complete vectoring nozzle.

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