baidu english translator:
1 aircraft thrust vector technology is to change the direction of the engine exhaust to provide a stronger steering torque of the aircraft. Aircraft with thrust vector technology application can give the fighter super maneuverability, STOL and low detectability, greatly improve the fighter's combat effectiveness and viability. The United States, Russia and other developed countries will be the priority of its development as an important technology.
In the research of thrust vector technology, it is the key to change the direction of the engine exhaust, that is, the research of thrust vector nozzle is the key and decisive part. Axial symmetrical vector nozzle (AVEN) is a kind of thrust vector nozzle developed on the conventional mechanical convergent divergent nozzle, which is changed by the deflection of the divergent section of the nozzle. On the whole aircraft thrust vector technology, AVEN has a simple, lightweight, low risk characteristics, the aircraft, the main engine of the modified requirements of small, is the implementation of thrust vector technology, the best nozzle program. AVEN technology research goal is to develop AVEN test pieces to complete the target platform turbofan type, and realize the hot state test.
2 research objectives and approaches
Aven to keep axisymmetric divergent nozzle area and area than regulatory function based on implementation of deflection of the diffuser, and other mechanical equipment is the important difference is that aven is a kind of complex spatial multi degree of freedom mechanical movement, the people are most concerned about is how to make such mechanical device movement, how to realize the deflection, how to ensure that the deflection after numerous, overlapping component coordinated motion and no clamping stagnation, how to determine the correct movement. So research ideas is from capture the movement mechanism of the staff, from the computer simulation to the model, when after the success of the model, immediately decided in a converted into I:1 principle prototype so as to overcome the key technology research of thrust vectoring nozzle movement mechanism.
Because of the technical difficulty of AVEN research, the lack of domestic technical reserves, there is no similar mechanical device for reference, to find out the key technology to solve the problem is not possible. In view of this situation, through self-reliance, progressive approach, from the computer simulation to model, from the model to the kind, from the cold to the hot, phase decomposition of key technologies, one by one to take technical measures and according to need is verified by computer simulation or test and other methods. At the same time, the decomposition the key technology of the next stage, so the cycle development, gradually overcome the key technologies of Aven stages, the final completion of the target platform turbofan type aven test development and hot commissioning.
A VI test development is a involving gas, mechanism, structure, intensity and control, materials and processes, etc. many technology research topic, each have a lot of innovative research content, the concurrent engineering technology to coordinate multiple projects, the development of quality have been got great benefits.
3 computer simulation
Aven is a kind of complex spatial multi degree of freedom motion mechanism, typical of Aven mechanism has about 200 a moving member and more than 300 sports vice, these components in an annular space cross overlapping movement, only by artificial means to study the movement mechanism and the relationship between the is impossible. In the development process of the aven experiment, using a large number of computer simulation technology, the completion of the movement mechanism research, motion component design and assembly process and inspection technology in many aspects of work, not only effectively relationship research cycle, but also improve the accuracy of the design of the structure.
3.1 motion mechanism simulation
Using C language to compile aven main moving components dynamic motion simulation software, of Aven's movement mechanism, the main moving components of the mutual relations exercise, A9 manipulation position in relation to the cylinder and nozzle divergent section, thus give aven's position and motion control law.
32 entity simulation
In the research process of AVEN, especially the development of the whole size cold and hot test piece, the computer simulation technology is applied to complete the closed-loop design of AVEN according to the following working process:
(1) according to the aerodynamic design scheme and the simulation results of motion mechanism, the design of the structure is carried out;
(2) according to the scheme of initial size of real 3D computer modeling, computer virtual assembly simulation, and computer aven entity mechanism motion simulation and structure scheme to examine the rationality and movement accuracy.
(3) the main components of the 3D model to provide strength design strength, stiffness check and preliminary structural strength optimization;
(4) the preliminary control law is given, and the scheme design of the hydraulic system and the controller is carried out in parallel;
(5) the scheme design of small closed loop process, after more or less several times repeated, structure design scheme can be optimized, after the subsequent design iterations, structure design scheme can be optimized, subsequent design work have good foundation. After the completion of the main components of the engineering design, according to the actual structure of the 3D entity simulation of Aven, to verify the structural design, reasonable pass and control of correctness, part and check the processing performance and test the assembly process performance.
According to this design procedure can be before the hardware processing complete virtual assembly and virtual experiment, effectively ruled out most of ten blind spots and failure, greatly improve the quality of test research, shorten the development cycle, save development funding.
On the basis of these simulations, the program design and motion simulation software of AVEN mechanism is worked out, which can quickly and accurately complete the design and optimization of AVEN.
4 motion mechanism and model test
In order to verify the correctness of the computer simulation results, the mechanism of AVE.N motion is further studied, and the mechanism of cold motion and the development and testing of the model test specimens are also studied.
Firstly, the diffusion aven section shrinkage than motion mechanism test pieces, research on motion mechanism of controllable performance and deflection when the main component of motion coordination; thereafter, the development of the size of the real engine of Ling state principle prototype, of Aven motion mechanism and motion mechanism structure the specific structure of the feasibility and the sub agency implementation method, research and verify the control principle and control system. Through to the two sets of test development and test to verify the correctness of the movement mechanism of the computer simulation results, to moving mechanism of Aven intuitive, clear understanding; master the manipulation of Aven methods; find the optimal vector angle; has completed the development of level, semi automatic controller; to determine the next step needed to solve the key technology.
5 to capture key technologies and test by hot test
In cold test on the basis of the research, according to the technical achievements of the aircraft division of the L2 request and preliminary work, decomposition of the key technology, completed the hot state test device and its control system design, construction and fades, the realization of the test on the platform of turbojet engine afterburner state. Hot bench test a test, to verify the eight main technical key, namely the gas dynamic performance, structural design, strength and stiffness analysis, automatic control, materials and technology, cooling and heat insulation, sealing and sealing, testing and trial car and the solving measures are successful for our self-developed aven technology demonstrator has laid a solid technical foundation.
6 technical validation and improvement of thermal state test pieces
On the basis of the 8 key technologies in the hot test
In order to overcome the other 4 key technologies, an improved thermal test is developed, which has been completed in two stages. The first stage of the completion of the trial the 558 vector cycles, test shows that, the test piece in fully inherit the second batch of machine all success, at the same time, to overcome the four key technologies designed to, design index of Aven has fully reached aircraft division proposed 12 requirements. Due to the limitation of the test bench, the AVEN thermal state test can not be fully tested. For this, the adaptability of the test bench is transformed, and the three component force measuring system is added to the test bench. With three component force system of the test bed measurement and to improve thermal state test pieces were increased vector angle, increasing the experimental study on cyclic number vector, the maximum thrust vector angle reached 21 degrees, hot 10026 vector cycle number. Test results show that the AVEN thermal test piece has a certain reliability.
At the same time, the temperature distribution, stress distribution and thrust characteristic of the key components are obtained.
7 target platform, the hot state test standard in after serious analysis and summary of the above work, through to three basic gas dynamic scheme and two basic structure scheme optimization analysis to determine the target platform aven's final plan and the need to overcome the difficulty of
Aven inherited the former aven's all successful technical measures. Improvements have been made to all the shortcomings, finally completed the test target platform aven full afterburner. The target platform AVEN maintains the aerodynamic characteristics, the control law and the installation interface which are similar to the original nozzle of the target platform, and has good compatibility. Test results show that, under the conditions of large adjustment range and high load of the target platform, the AVEN motion of the target platform is flexible and accurate, the nozzle seal is good, the bearing system is reliable and effective.
AVEN has a new small integrated digital control system, and has a safe and reliable emergency system.
Target platform AVEN to achieve the following technical indicators:
(1) deflection position: 360 degree;
(2) vector angle: 17 degrees to 20 degrees;
(3) deflection rate: =120 Wx degrees to 180 degrees / second, Wy=Wz = 45 degrees -60 degrees / sec;
(4) the inward force structure, dimensions meet the requirements;
(5) emergency reset device for setting control system.
AVEN test results on the target platform show that:
(1) the range of nozzle adjustment fully meets the requirements of engine main engine.
(2) the inward force structure withstood a load thrust level
(3) the design of A8 is correct. Using the original digital electronic controller
3) A8 design is correct. Using the original digital electronic controller to achieve the A8 AVEN automatic control and the original control system is fully compatible, no need to change.
(4) A8 and A9 can be individually controlled, and can be linked to a given relationship, coordination is very good.
(5) A9 control system to achieve miniaturization, digital, integrated, stable and reliable work.
(6) the sealing piece, the adjustment piece and other components work reliably.
(7) AVEN emergency reset function is safe and reliable.
(8) in the engine asked, small loading state, part of the afterburner and full afterburner state, ave n deflection of main nozzle and gas dynamic parameters match well, working stability of mechanical system,
(9) dimensions and aerodynamic shape to meet the requirements of aircraft.
(1O) the vector of various working conditions are successfully measured in the test run
Temperature distribution, stress distribution and the efficiency of the engine.
Turbofan axisymmetric vectoring exhaust nozzle test is successful, the hot state test pieces to solve the 11 key technology measures are successful, the study of thrust vectoring nozzle and step onto a new level.
8 concluding remarks
Aven aven to maintain the existing engine received divergent nozzle all the functions and the same regulation control mode, the completion of the final will be alternative existing axisymmetric convergent divergent nozzle. The 3 and half generation aircraft with dominant maneuver.
Similarly, aven can according to push more than 10, pushing more than 12, 15 engine design, as the push than 10, pushing more than 12, pushing more than 15 a standard nozzle, our country of the 4th generation fighter with higher mobility, enhance China's air defense forces. Aircraft with thrust vector technology can Application in aircraft, and is expected to develop a suitable for shipboard without tail STOL aircraft and conventional layout VTOL aircraft (general layout of vertical taking off and landing of aircraft taking off and landing in a manner similar to rocket, taking off and landing on the mobile landing platform or middle ship helicopter landing platform.
Equipped with thrust vectoring aircraft engine after modification, as a new type of wing in ground effect aircraft or a WIG craft, greatly improve the assaulting capability, mobility and survival? Technology research and application of new design method, such as calculating machine simulation technology, new materials, such as Ni3AL research, new process (such as super plastic forming and diffusion connection) research and of defence technology and civilian technology development will be to promote.