【作者】 姜健；

【导师】 刘波；

【作者基本信息】 西北工业大学 ， 先进制造， 2022， 博士

【摘要】 推力矢量飞机过失速区试飞是我国飞行试验的新领域,与常规飞行包线相比,具有飞行速度低、迎角大、机动过程飞行状态急剧变化的显著特点,面临着较为突出的进气道与发动机相容性问题,也存在巨大的安全风险和技术难度,直接影响着飞行性能与安全。因此,摸清低速大迎角下的进气道性能特性和流场畸变、评估进气道/发动机相容性(简称:进/发相容性)则成为推力矢量飞机过失速区飞行试验亟需攻克的关键技术。本文是在国防重大项目的资助下开展的,涉及的推力矢量技术演示验证试飞是国内首次开展,其中过失速区的低速大迎角进气道试飞备受关注。通过辨识推力矢量飞机过失速区试飞的新特征,CFD仿真其进气道低速大迎角时的流场畸变,分析常规迎角进气道试飞技术的适用性,确定了低速大迎角进气道试飞所面临的流场测量、试飞风险控制、试飞方法设计、瞬态总压畸变评估等技术难题,形成了本文的主要研究方向及研究内容。为准确测量低速大迎角时进气道出口的流场,以获取丰富的流场信息为目标,引入了探针融合的理念,自主设计了集流场单点处总压/静压/动压同步测量的复合压力探针,研制了复合探针多模式总压畸变测量耙,满足了该飞机全包线范围的使用环境要求,实现了进气道出口稳态总压流场、静压流场、动态总压流场的同步测量,获取了丰富的试验数据,在大迎角区进气道性能特性和流场品质的准确测量、评估方法上有了新的突破。为降低低速大迎角区进气道试飞的风险,设计了“减速爬升→缓慢推杆→拉杆保持”和“减速爬升→缓慢推杆→拉杆保持→蹬舵”的迎角及侧滑角组合试飞动作、分叉树式的试飞方法、三段式的试飞方案,开发了进气道试飞辅助监视系统,引入了飞机模拟器、畸变预测手段,建立了风险预测评估、动作演练优化、试飞安全验证的多维一体化进气道试飞新模式,实现了低速大迎角进/发相容性试飞的风险最小、效率最高,突破了低速大迎角进气道试飞的风险控制与设计技术。为预估大迎角安全风险、优化试飞试验点的设计,提出了以试飞风险控制点为核心、中小迎角区有限试飞样本为基础、趋势预测与误差修正相融合的建模预测技术,并最终构建了新的大迎角/侧滑角组合时的进气畸变预测方法,降低了畸变预测的复杂度、难度,预测结果的精度显著提高,可有效地用于低速大迎角进气道试飞中的试验点的风险评估及优化;同时,提出了面向过程的动态建模试飞预测方法,通过试飞数据的回溯验证,结果表明该方法实现了试飞过程的动态建模、修模,从而在保证预测结果准确性的同时拓展了模型适用范围,提高了迎角/侧滑角包线拓展试飞的风险预估能力。综合应用上述的技术和方法,在保证进气道与发动机相容性正常的情况下,飞机进气道试飞中在过失速区将迎角拓展到了其常规迎角边界的4.17倍。研究表明:在过失速区,进气道总压恢复系数随着迎角、侧滑角的增大而减小,进气道性能下降;周向畸变指数、紊流度、综合畸变指数随迎角、侧滑角的增大而增大,进气道出口的总压流场畸变增大。基于此确定的飞机中低空大迎角、侧滑角试飞“安全岛”合理可行,并在多次过失速机动试飞和2018年的珠海航展表演中得到验证。围绕过失速机动过程中的瞬态总压畸变,从畸变强度与流场构型两个维度入手,引入了基于相邻环模型的瞬时周向畸变指数、基于偏差模型的瞬时流场偏离度等,定义了畸变瞬时最大值、流场偏离峰值等指标,建立的指标定量表征与图形分析相结合的瞬态总压畸变评估方法通过了试飞数据对比验证,结果表明该评估方法具有工程实用性。本文研究突破了进气道多维压力流场同步测量技术、基于试飞数据的进气畸变建模与预测方法、低速大迎角进/发相容性试飞的动作设计与安全控制方法、瞬态总压畸变评估等关键试飞技术,实现了国内进/发相容性飞行试验领域的重大技术进步,可以为后续未来先进战斗机的飞行试验提供科学依据和技术基础。更多还原

【Abstract】 The post-stall zone flight test of the aircraft with thrust vectoring control(TVC)is a newly-emerged part in Chinese flight test field.Compared with conventional flight envelope,this flight test is characterized by low flight speed,high angle of attack(AOA)and abrupt change of flight state during maneuver.It is faced with prominent inlet/engine compatibility issue,immense safety risks and technical challenge,directly affecting flight performance and safety.Therefore,the post-stall zone flight test of TVC aircraft badly needs critical technical breakthroughs to be made in understanding thoroughly the engine inlet performance characteristics and the flow field distortion level at low speed and high AOA as well as assessing the compatibility of the inlet and the engine.Supported by an important national defense project,the research was carried out.The concerned demonstration flight test of thrust vectoring technology was implemented for the first time at home and the inlet flight test at low speed and high AOA attracted a great deal of attention.Technical challenges faced by the inlet flight test at low speed and high AOA form the main research direction and content of this thesis such as flow field measurement,control of flight test risk,design of flight test methods and evaluation of transient total pressure distortion.These challenges were determined by identifying the new characteristics of the flight test of TVC aircraft over post-stall zone,conducting CFD simulation of the inlet flow field distortion at low speed and high AOA,and analyzing the applicability of the inlet flight test technique at conventional AOA.In order to accurately measure the flow field of inlet outlet at low speed and high AOA,aiming to obtain abundant flow-field information,the concept of compound probe was adopted.An integrated probe was independently designed which can measure total pressure/static pressure/dynamic pressure at a single point simultaneously.Along with it,a multi-model rake for total pressure distortion measurement with these compound probes was developed.This rake satisfies the test environment requirements throughout the overall envelope of the test plane.Thanks to these creations,synchronous measurement was achieved at the flow field of the inlet outlet for steady total pressure,static pressure and dynamic pressure,providing large amount of test data which facilitated breakthroughs in the methods of evaluating and measuring the inlet performance characteristics and flow field quality over high AOA zone in a more precise way.In order to reduce the risk of the inlet flight test at low speed over high AOA zone,the flight maneuver combining AOA and sideslip angle by“deceleration climbing→slow pushrod→stick pulling holding”and“deceleration climbing→slow pushrod→stick pulling holding→push the rudder”,the tree structure flight test method and three-step test plan were designed.An auxiliary monitoring system for inlet flight test was developed.In addition,a new multi-dimensional incorporate pattern for inlet flight test integrating risk prediction and evaluation,maneuver optimization and flight test safety verification was established by introducing flight simulator and distortion prediction method.This pattern minimized the risk of and maximized the efficiency of the inlet/engine compatibility flight test at low-speed and high AOA.Breakthroughs were made in the technologies of the risk control and design for the inlet flight test at low-speed and high-AOA.To estimate the risk of flight test at high AOA and optimize the design of flight test points,a modeling-based prediction technique was proposed.It integrates tendency prediction and error correction by concentrating on flight test risk control points and on the basis of the limited number of test samples over medium and low AOA zones.Finally,a new method for predicting the inlet distortion with high AOA and sideslip angle combined was developed.Thanks to this method,the distortion prediction becomes less complex,easier and the prediction results much more accurate.This method was effective for the risk assessment and optimization of low speed high AOA inlet flight test points.At the same time,the process-oriented dynamic modeling prediction flight test method was proposed,by which the dynamic modeling and correction during the flight test were achieved through recalling verification of the flight test data.The Result shows this method not only ensures the accuracy of the prediction results,but also expands the applicable scope of the model,improving the ability of predicting the risk of AOA/sideslip angle envelope expansion flight test.The AOA was extended to 4.17 times of conventional AOA boundary in the post-stall zone by applying the above technologies and methods comprehensively during the inlet flight test so long as the compatibility of the inlet with the engine was ensured.The research shows that the recovery coefficient of inlet total pressure decreases with the increase of AOA and sideslip angle over post-stall zone,leading to poorer inlet performance;and that the circumferential distortion index,turbulence intensity and comprehensive distortion index all increase with the growth of the AOA and sideslip angle;and that the total pressure distortion of the inlet outlet flow field increases too.Based on these findings,a“safety island”was determined for the aircraft high AOA and sideslip angle flight test either at low-or medium-levels.The safety island is reasonable and feasible,which was verified by many post-stall maneuver flight tests and the flying demonstration on the 2018 Zhuhai Air Show.In terms of the transient total pressure distortion in the process of post-stall maneuvering,multiple indicators such as maximum instantaneous distortion,flow filed deviation peak and others were defined by introducing the instantaneous circumferential distortion index based on the adjacent ring model and the transient flow field deviation index based on the deviation model,and considering both distortion intensity and flow field configuration dimension.As a result,a transient total pressure distortion evaluation method was developed which combines quantitative index and graphical analysis.The method was verified through comparing flight test data and was proved practical in engineering.The research of this thesis breaks through the key flight test techniques including synchronous measurement technique for inlet multidimensional pressure flow field,inlet distortion modeling and prediction method based on flight test data,maneuver design and safety control method for inlet/engine compatibility flight test at low speed and high AOA,and evaluation method of the transient total pressure distortion.A significant progress in the domestic inlet/engine compatibility flight test techniques was achieved,providing scientific basis and technical foundation for the subsequent flight tests of future advanced fighters.更多还原