Aerodynamic load design method based on extension nozzle use profile action link

Abstract

The invention discloses an aerodynamic load design method based on an action link of a section used by an extension nozzle, which comprises the following steps of: obtaining an aerodynamic load section according to a preset action link used by the extension nozzle; and carrying out aerodynamic load design on the aerodynamic load profile to obtain aerodynamic load conditions. According to the method, the aerodynamic load of each use section can be comprehensively identified and analyzed, and the defects of aerodynamic load design of the extension nozzle are overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of aerodynamic optimization design, and in particular relates to an aerodynamic load design method based on an extended nozzle using a profile action link. Background Art

[0002] With the increasing requirements for the thrust-to-weight ratio of rocket engines, the use of extended nozzle technology to shorten the overall length of the rocket has received increasing attention. In order to reduce weight, the extension cone of the extended nozzle is mostly made of non-metallic materials, but these materials have obvious anisotropy and low material strength. The defects of the existing technology are: during the flight of the rocket, the extended nozzle needs to increase the expansion ratio to improve the engine performance, while also having to withstand the complex aerodynamic load environment under the flight profile. However, the anisotropy and low strength characteristics of non-metallic materials make it easy for them to fail structurally under complex aerodynamic loads, resulting in reduced reliability.

[0003] In addition, the existing aerodynamic load identification technology is unable to fully and accurately identify and analyze the aerodynamic load of the extended nozzle under different flight profiles. It is difficult to ensure the strength and rigidity of the structure during the design process, which affects the overall performance and safety of the rocket. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide an aerodynamic load design method based on the extended nozzle use profile action link, which can comprehensively identify and analyze the aerodynamic loads of each use profile, make up for the shortcomings of the extended nozzle aerodynamic load design, efficiently and reliably complete the extended nozzle aerodynamic load design, and improve the design efficiency.

[0005] The object of the present invention is achieved through the following technical solutions: a method for designing an aerodynamic load based on a profile action link used by an extended nozzle, comprising: obtaining an aerodynamic load profile according to a preset action link used by the extended nozzle; and performing an aerodynamic load design on the aerodynamic load profile to obtain an aerodynamic load condition.

[0006] In the above-mentioned aerodynamic load design method based on the extended nozzle profile action link, the aerodynamic load profile includes the inter-stage separation high dynamic load profile, the load profile before the extended nozzle is deployed, the load profile during the extended nozzle deployment process and the load profile after the extended nozzle is deployed.

[0007] In the above-mentioned aerodynamic load design method based on the profile action link of the extended nozzle, the aerodynamic load condition of the inter-stage separation high dynamic load profile is the internal and external pressure difference of the extended nozzle.

[0008] In the above-mentioned aerodynamic load design method based on the extended nozzle using the profile action link, the aerodynamic load conditions of the load profile before the extended nozzle is deployed are: the maximum pressure on the surface of the extended nozzle before deployment and the aerodynamic coefficient of the extended nozzle before deployment.

[0009] In the above-mentioned aerodynamic load design method based on the extended nozzle profile action link, the aerodynamic load conditions of the load profile during the extended nozzle deployment process are: the internal and external pressure difference of the extended nozzle surface and the aerodynamic force coefficient during the extended nozzle deployment process.

[0010] In the above-mentioned aerodynamic load design method based on the extended nozzle using the profile action link, the aerodynamic load conditions of the load profile after the extended nozzle is deployed are: the maximum pressure on the extended nozzle surface after deployment and the aerodynamic coefficient after the extended nozzle is deployed.

[0011] In the above-mentioned aerodynamic load design method based on the extended nozzle using the profile action link, the block internal and external pressure difference of the extended nozzle is obtained by the following formula: ; in, To extend the nozzle block internal and external pressure difference, is the inner surface pressure of the block element, is the outer surface pressure of the block element, is the infinitesimal area of ​​the block extending the nozzle.

[0012] In the above-mentioned aerodynamic load design method based on the profile action link of the extended nozzle, the step of obtaining the maximum pressure on the surface of the extended nozzle before deployment includes: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum before the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle before deployment from the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed.

[0013] In the above-mentioned aerodynamic load design method based on the use of a profile action link for an extended nozzle, the internal and external pressure difference on the surface of the extended nozzle includes the internal and external pressure difference on the windward surface of the extended nozzle and the internal and external pressure difference on the leeward surface of the extended nozzle; wherein, the step of obtaining the internal and external pressure difference on the windward surface of the extended nozzle is: selecting the state of the maximum swing angle of the nozzle during the deployment of the extended nozzle to simulate the internal and external flow fields of the extended nozzle, and obtaining the internal and external pressure distribution of the busbar of the windward surface of the extended nozzle, and obtaining the internal and external pressure difference on the windward surface of the extended nozzle according to the internal and external pressure distribution of the busbar of the windward surface of the extended nozzle; the step of obtaining the internal and external pressure difference on the leeward surface of the extended nozzle is: selecting the state of the maximum swing angle of the nozzle during the deployment of the extended nozzle to simulate the internal and external flow fields of the extended nozzle, and obtaining the internal and external pressure distribution of the busbar of the leeward surface of the extended nozzle, and obtaining the internal and external pressure difference on the leeward surface of the extended nozzle according to the internal and external pressure distribution of the busbar of the leeward surface of the extended nozzle.

[0014] In the above-mentioned aerodynamic load design method based on the profile action link of the extended nozzle, the step of obtaining the maximum pressure on the surface of the extended nozzle after it is deployed includes: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum after the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle after it is deployed from the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention can comprehensively identify and analyze the aerodynamic loads of each use section, make up for the shortcomings of the aerodynamic load design of the extended nozzle, efficiently and reliably complete the aerodynamic load design of the extended nozzle, and improve the design efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 is a flow chart of an aerodynamic load design method based on an extended nozzle using a profile action link provided by an embodiment of the present invention; Figure 2 is a schematic diagram of an extended nozzle provided in an embodiment of the present invention; Figure 3 is a schematic diagram of the distributed pressure difference on the windward surface of the extended nozzle during the deployment process provided by an embodiment of the present invention; Figure 4 is a schematic diagram of the distributed pressure difference on the leeward side during the deployment of the extended nozzle provided by an embodiment of the present invention; Figure 5 It is a schematic diagram of the surface pressure distribution after the extended nozzle is deployed according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] With the increasing requirements for the thrust-to-weight ratio of rocket engines, the use of extended nozzle technology to shorten the overall length of the rocket has received increasing attention. In order to reduce weight, the extension cone of the extended nozzle is mostly made of non-metallic materials, which have obvious anisotropy and low material strength.

[0019] During the rocket flight, the extended nozzle must increase the expansion ratio to improve engine performance, and withstand the complex aerodynamic load environment under the flight profile. Therefore, it is necessary to conduct in-depth and detailed identification and analysis of the entire design profile, and further carry out design work such as structural strength and stiffness from each profile.

[0020] Figure 1 FIG. 1 is a flow chart of an aerodynamic load design method based on an extended nozzle using a profile action link provided by an embodiment of the present invention. Figure 1 As shown, the method includes the following steps: obtaining an aerodynamic load profile according to a preset action link used by the extended nozzle; and performing an aerodynamic load design on the aerodynamic load profile to obtain an aerodynamic load condition.

[0021] The aerodynamic load profile includes the high dynamic load profile of stage separation, the load profile before the extended nozzle is deployed, the load profile during the extended nozzle deployment process, and the load profile after the extended nozzle is deployed.

[0022] The pressure difference between the inner and outer blocks of the extended nozzle is obtained by the following formula: ; in, To extend the nozzle block internal and external pressure difference, is the inner surface pressure of the block element, is the outer surface pressure of the block element, is the infinitesimal area of ​​the block extending the nozzle.

[0023] The aerodynamic load conditions of the load profile before the extended nozzle is deployed are: the maximum pressure on the extended nozzle surface before deployment and the aerodynamic coefficient before deployment of the extended nozzle.

[0024] The steps for obtaining the maximum pressure on the surface of the extended nozzle before it is deployed include: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum before the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle before it is deployed from the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed.

[0025] The aerodynamic load conditions of the load profile during the extended nozzle deployment process are: the internal and external pressure difference of the extended nozzle surface and the aerodynamic force coefficient during the extended nozzle deployment process.

[0026] The internal and external pressure difference of the extended nozzle surface includes the internal and external pressure difference of the extended nozzle windward surface and the internal and external pressure difference of the extended nozzle leeward surface; wherein, the step of obtaining the internal and external pressure difference of the extended nozzle windward surface is: selecting the state of the maximum swing angle of the nozzle during the deployment of the extended nozzle to simulate the internal and external flow fields of the extended nozzle, obtain the internal and external pressure distribution of the generatrix of the extended nozzle windward surface, and obtain the internal and external pressure difference of the extended nozzle windward surface according to the internal and external pressure distribution of the generatrix of the extended nozzle windward surface. The step of obtaining the internal and external pressure difference of the extended nozzle leeward surface is: selecting the state of the maximum swing angle of the nozzle during the deployment of the extended nozzle to simulate the internal and external flow fields of the extended nozzle, obtain the internal and external pressure distribution of the generatrix of the extended nozzle leeward surface, and obtain the internal and external pressure difference of the extended nozzle leeward surface according to the internal and external pressure distribution of the generatrix of the extended nozzle leeward surface.

[0027] The aerodynamic load conditions of the load profile after the extended nozzle is deployed are: the maximum pressure on the extended nozzle surface after deployment and the aerodynamic coefficient after the extended nozzle is deployed.

[0028] The steps for obtaining the maximum pressure on the surface of the extended nozzle after it is deployed include: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum after the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle after it is deployed from the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed.

[0029] Specifically, the method comprises the following steps: (1) According to the extended nozzle operation link, the aerodynamic load profile is sorted out.

[0030] Figure 2 Schematic diagram of the extended nozzle provided by the embodiment of the present invention. Figure 2 , according to the timed action link, the aerodynamic load profile faced by the extended nozzle is sorted out. Starting from the engine ignition, the aerodynamic load profile experienced is: the high dynamic load profile of the interstage separation; the load profile before the extended nozzle is deployed; the load profile during the extended nozzle deployment; the load profile after the extended nozzle is deployed.

[0031] (2) Carry out aerodynamic load design and formulate aerodynamic load conditions.

[0032] (21) Identification of high dynamic loads during interstage separation: The interstage separation process is accompanied by the relative motion of the high-pressure jet and the separation body, and the interstage flow field exhibits high dynamic and strong non-uniformity characteristics. It is necessary to analyze the dynamic changes of the nozzle surface pressure under time series changes based on the rapid dynamic changes of the flow field to further analyze the modal response of the nozzle. The load form is the internal and external pressure difference of the extended nozzle block (the extended nozzle is divided into multiple blocks according to axial equidistance and circumferential equidistance). .

[0033] For high dynamic loads of stage separation, the external flow field under typical working conditions is at the lowest altitude, the internal pressure of the engine is at the maximum, and the pressure holding is considered for the longest time. The time-series internal and external pressure differences of different parts of the extension cone are extracted.

[0034] Pressure difference between inside and outside of the block The formula is:

[0035] in, To extend the nozzle block internal and external pressure difference, is the inner surface pressure of the block element, is the outer surface pressure of the block element, is the microelement area of ​​the block of the extended nozzle, where the block is divided into a plurality of grid units, each of which is a microelement.

[0036] (22) Load identification before the extended nozzle is deployed: After the stage separation is completed, the extended nozzle is still in a retracted state and is affected by the external flow during the entire flight of the rocket. In particular, the nozzle is relatively large in size exposed relative to the rocket body when it is in a swinging state. It is necessary to analyze the influence of the lateral concentrated force and distributed force loads after flow separation and reattachment on the nozzle structure. The load form is the maximum pressure on the surface of the extended nozzle before deployment and the aerodynamic coefficients of the extended nozzle before deployment (axial force coefficient CA1, normal force coefficient CN1, pitch moment coefficient CMZ1).

[0037] For the load before the extended nozzle is deployed, the typical working condition external flow field is the lowest height state, and the nozzle swing angle considers the maximum state. The pressure distribution of different generatrixes of the extended cone is extracted, and the flow pressure Q and reference area S ref Cp is dimensionless, and the aerodynamic coefficients (CA1, CN1, CMZ1) are obtained to give the segmented aerodynamic force.

[0038] The steps for obtaining the maximum pressure on the surface of the extended nozzle before it is deployed are as follows: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum before the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle before it is deployed from the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed.

[0039] (23) Load identification during the extension nozzle deployment process: During the extension nozzle deployment process, the flow is extremely complex due to the coupling of the internal and external flow of the engine jet and the external aerodynamic turbulence. It is necessary to analyze the force of the extension cone during this complex process. The load form is the internal and external pressure difference of the extension nozzle surface and the aerodynamic coefficients of the extension nozzle deployment process (axial force coefficient CA2, normal force coefficient CN2, pitch moment coefficient CMZ2).

[0040] For the load of the extension cone deployment process, the flow fields inside and outside the typical working condition are taken as standard state, and two working conditions are considered according to the swing angle of 0° and 6°. The pressure distribution of different generatrixes of the extension cone at different times is extracted, and the aerodynamic coefficient is obtained by dimensionless transformation of the flow pressure and reference area, and the segmented aerodynamic force is given.

[0041] The internal and external pressure difference of the extended nozzle surface includes the internal and external pressure difference of the windward surface of the extended nozzle and the internal and external pressure difference of the leeward surface of the extended nozzle; The steps of obtaining the internal and external pressure difference of the windward surface of the extended nozzle are as follows: the internal and external flow fields of the extended nozzle are simulated when the nozzle has the maximum swing angle during the deployment of the extended nozzle, and the internal and external pressure distribution of the generatrix of the windward surface of the extended nozzle is obtained. According to the internal and external pressure distribution of the generatrix of the windward surface of the extended nozzle, the internal and external pressure difference of the windward surface of the extended nozzle is obtained, such as Figure 3 shown.

[0042] The steps of obtaining the internal and external pressure difference of the leeward surface of the extended nozzle are as follows: the internal and external flow fields of the extended nozzle are simulated when the nozzle has the maximum swing angle during the deployment of the extended nozzle, and the internal and external pressure distribution of the generatrix of the leeward surface of the extended nozzle is obtained; and the internal and external pressure difference of the leeward surface of the extended nozzle is obtained according to the internal and external pressure distribution of the generatrix of the leeward surface of the extended nozzle, such as Figure 4 shown.

[0043] (24) Load identification after the extended nozzle is deployed: After the nozzle is fully deployed, the exposed size relative to the rocket body is larger, and it is subjected to greater lateral forces under the action of the external flow. It is necessary to analyze the impact of lateral concentrated force and distributed force loads on the nozzle structure. The load form is the maximum pressure on the surface after the extended nozzle is deployed and the aerodynamic coefficients after the extended nozzle is deployed (axial force coefficient CA3, normal force coefficient CN3, pitch moment coefficient CMZ3).

[0044] For the load after the extended nozzle is deployed, the typical working condition external flow field is the lowest height state, and the nozzle swing angle is considered to be the maximum state. The pressure distribution of different generatrixes of the extended cone is extracted, and the aerodynamic coefficient is obtained by dimensionless transformation of the flow pressure and reference area, and the segmented aerodynamic force is given.

[0045] The steps of obtaining the maximum pressure on the surface of the extended nozzle after deployment are as follows: simulating the extended nozzle flow field when the extended nozzle is deployed at the lowest flight altitude and the maximum nozzle swing angle, obtaining the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle after deployment from the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed. Figure 5 shown.

[0046] The aerodynamic force is calculated as follows:

[0047]

[0048]

[0049] In the formula, , are the axial force and normal force acting on the nozzle, is the reference area of ​​the force coefficient of the extended nozzle, is the reference length of the force coefficient of the extended nozzle, is the pitch moment acting on the nozzle, is the position of the pressure center (from the swing center). The axial force coefficient CA1, axial force coefficient CA2 and axial force coefficient CA3 can all be regarded as axial force coefficient CA, the normal force coefficient CN1, normal force coefficient CN2 and normal force coefficient CN3 can all be regarded as normal force coefficient CN, and the pitching moment coefficient CMZ1, pitching moment coefficient CMZ2 and pitching moment coefficient CMZ3 can all be regarded as pitching moment coefficient CMZ.

[0050] This embodiment provides a reasonable and effective aerodynamic load identification technology for the flight profile used by the extended nozzle, comprehensively identifies and analyzes the aerodynamic loads under each action link of the extended nozzle, and is used for load and structural design analysis, so as to efficiently and reliably complete the aerodynamic load design of the extended nozzle, thereby improving the design efficiency.

[0051] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for designing aerodynamic loads based on an extended nozzle using a profile action link, characterized in that include: The aerodynamic load profile is obtained according to the preset action chain used by the extended nozzle; Aerodynamic load design is carried out on the aerodynamic load profile to obtain the aerodynamic load conditions.

2. The aerodynamic load design method based on the extended nozzle using the profile action link according to claim 1 is characterized in that: The aerodynamic load profile includes a high dynamic load profile of interstage separation, a load profile before the extended nozzle is deployed, a load profile during the extended nozzle deployment, and a load profile after the extended nozzle is deployed.

3. The aerodynamic load design method based on the extended nozzle using profile action link according to claim 2 is characterized in that: The aerodynamic load condition of the stage separation high dynamic load profile is the pressure difference inside and outside the extended nozzle.

4. The aerodynamic load design method based on the extended nozzle using profile action link according to claim 2 is characterized in that: The aerodynamic load conditions of the load profile before the extended nozzle is deployed are: the maximum pressure on the extended nozzle surface before deployment and the aerodynamic coefficient before deployment of the extended nozzle.

5. The aerodynamic load design method based on the extended nozzle using profile action link according to claim 2, characterized in that: The aerodynamic load conditions of the load profile during the extended nozzle deployment process are: the internal and external pressure difference of the extended nozzle surface and the aerodynamic force coefficient during the extended nozzle deployment process.

6. The aerodynamic load design method based on the extended nozzle using profile action link according to claim 2 is characterized in that: The aerodynamic load conditions of the load profile after the extended nozzle is deployed are: the maximum pressure on the extended nozzle surface after deployment and the aerodynamic coefficient after the extended nozzle is deployed.

7. The aerodynamic load design method based on the extended nozzle using the profile action link according to claim 3 is characterized by: The pressure difference between the inner and outer blocks of the extended nozzle is obtained by the following formula: ； in, To extend the nozzle block internal and external pressure difference, is the inner surface pressure of the block element, is the outer surface pressure of the block element, is the infinitesimal area of ​​the block extending the nozzle.

8. The aerodynamic load design method based on the extended nozzle using profile action link according to claim 4 is characterized in that: The steps for obtaining the maximum pressure on the surface of the extended nozzle before it is deployed include: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum before the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle before it is deployed from the pressure distribution of the generatrix of the windward surface before the extended nozzle is deployed.

9. The aerodynamic load design method based on the extended nozzle using profile action link according to claim 5, characterized in that: The internal and external pressure difference of the extended nozzle surface includes the internal and external pressure difference of the windward surface of the extended nozzle and the internal and external pressure difference of the leeward surface of the extended nozzle; wherein, The steps of obtaining the internal and external pressure difference of the windward surface of the extended nozzle are as follows: simulating the internal and external flow fields of the extended nozzle when the nozzle has the maximum swing angle during the deployment of the extended nozzle, obtaining the internal and external pressure distribution of the generatrix of the windward surface of the extended nozzle, and obtaining the internal and external pressure difference of the windward surface of the extended nozzle according to the internal and external pressure distribution of the generatrix of the windward surface of the extended nozzle; The steps for obtaining the internal and external pressure difference of the leeward side of the extended nozzle are as follows: the internal and external flow fields of the extended nozzle are simulated when the nozzle has the maximum swing angle during the deployment of the extended nozzle, and the internal and external pressure distribution of the generatrix of the leeward side of the extended nozzle is obtained; and the internal and external pressure difference of the leeward side of the extended nozzle is obtained according to the internal and external pressure distribution of the generatrix of the leeward side of the extended nozzle.

10. The aerodynamic load design method based on the extended nozzle using the profile action link according to claim 6, characterized in that: The steps for obtaining the maximum pressure on the surface of the extended nozzle after it is deployed include: simulating the extended nozzle flow field when the flight altitude is the lowest and the nozzle swing angle is the maximum after the extended nozzle is deployed, obtaining the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed, and selecting the maximum pressure on the surface of the extended nozzle after it is deployed from the pressure distribution of the generatrix of the windward surface after the extended nozzle is deployed.

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