IMECH-IR  > 高温气体动力学国家重点实验室
高超声速分立悬挂式气动力测量理论与技术
英文题名Theories and Technologies for the Components-Uncoupled Suspension Balance of Hypersonic Aerodynamic Measurement
孟宝清
导师姜宗林
2018-05-21
学位授予单位中国科学院大学
学位授予地点北京
学位类别博士
学位专业流体力学
关键词高超声速 大型激波风洞 气动力测量 大尺度模型 分立悬挂式
摘要

高超声速流动的真实气体效应研究以及带动力一体化飞行器研制是目前先进空天飞行技术领域研究面临的两大困难。热化学反应尺度以及发动机/飞行器的强耦合效应不随模型缩尺而变化,高超声速流动气动力实验研究需要采用大尺度模型,以极小化热化学反应不可缩尺的影响。复现高超声速飞行条件激波风洞(JF12复现风洞)可复现马赫数5~9飞行条件,实验模型尺度可长达6m,为气动力实验提供了良好平台,但是传统的激波风洞气动力测量技术面临挑战。首先,传统的天平技术由于刚度不足、流场干扰较大、实验时间短、无法满足大尺度模型气动力测量需求。另外,传统的集成式天平结构不可避免地带来了测力分量间的干扰,限制了气动天平测量精度的进一步发展。为了发展JF12复现风洞的气动力测量技术,本论文提出了一种分量解耦悬挂式(简称分立悬挂式)气动力测量新方法,具有支撑刚度高、对流场干扰小、六量测力元件分立的优点。论文完成了新气动天平的理论发展、技术建立、天平设计、性能校测和实验验证。取得的主要创新成果如下:

1.           提出分量解耦悬挂式高超声速气动力测量方法,基于静态以及动态方程,构建气动力与杆系内力之间的理论解。由空间力系平衡方程得到的静态理论解与实验结果符合良好,其杆系合力与加载力偏差小于2%。动态理论解基于多自由度振动方程得到,为风洞内动态测力提供理论支撑。杆内力与气动力一一对应,系数矩阵存在精确理论解。而传统测力天平二者间无理论解,需校准实验获得系数矩阵。

2.           从振动系统广义振型矩阵出发,提出了两平面与尾撑正交组合的低干扰设计方案,构建了分立悬挂式天平的整体结构布置方式。发展的刚度调节理论为设计方案的详细参数拟定提供快速、直接的解析公式。研究结果表明,新方法测力系统可调参数达到5~6个,刚度调节灵活。将低干扰以及刚度需求作为约束条件,对杆系布置平面位置、平面个数、面内杆件数量、尾撑形式的影响规律开展研究,提出了杆系布置准则。基于测力理论需求,发展了空间几何参数一站式测量方法,提高了测力高精度,并研制了基于空间杆系的内力自平衡轴向天平,解决了轴向预紧导致大变形的难题。应用HB2标模开展风洞动态测力验证实验,测力系统各分量在实验时间内均能获得3~6有效周期信号,轴向力系数比国军标偏差优于2%,重复性精度优于1.8%。进一步开展了带动力一体化飞行器实验,对于类似X-51A全尺度飞行器模型,测力系统刚度特性良好、测力的重复性精度高。

3.           为了极小化分立悬挂式测力方法杆系支撑对流场干扰,将飞行器表面-圆柱杆简化为平板-半无限长圆柱模型,通过数值求解三维N-S方程,得到飞行器表面以及杆表面的流场特征结构。考虑平板表面气动力增量量级大小以及杆表面气动力分布特性及影响,发现单杆对飞行器表面气动干扰影响低于0.5%,杆系的对称布置使得气动增量相互抵消,干扰影响将下降一个量级,影响可扣除。

4.           提出激波风洞起动气动冲击载荷建模方法,得到激波风洞起动波系衍化过程,获得了冲击载荷近似理论解和冲击载荷的频率特性。进一步结合测力系统强迫振动特性,理论推导了“能量因子”参数具体表达式,从解析解所包含的诸多简谐载荷中“挑选”3-5个载荷,达到与原载荷“激励能量”上相近。载荷建模结合了冲击载荷特性,给出了天平设计约束条件的初步结果。

 

英文摘要

The real-gas effect and development of engine-integrated aircraft are the two challenges for the advanced technologies study of space-aeronautics flight. The reaction scale and the coupling effects of airframe and engine remain unchanged when the test model is reduced in its size in the wind-tunnel tests. That is, the large-scale aircraft model is needed for the ground test of hypersonic flow, which could minimize the effects induced by unchanged scale of chemical reaction. The Long test-Duration Hypervelocity Detonation driven Shock Tunnel (JF12 flight condition-reproducing tunnel ) is the world’s largest shock tunnel which is capable of reproduce the true hypersonic flight simulation with Mach numbers from 5 to 9. The lengths of its aircraft model are up to 6m and JF12 shock tunnel provides an excellent platform for the aerodynamic measurements. However, aerodynamic force measurement for a large-scale aircraft model by traditional method is confronted with great challenges. Poor stiffness and large interference to flow field place great limits to the aerodynamic measurements for large scale models in impulse tunnel. Moreover, the integrated structure of balance causes inevitable interference among force components, which limits the further improvement of the accuracy. To develop aerodynamic measurement technologies in the JF12 shock tunnel, this study presents a novel method named as Components-Uncoupled Suspension Balance (CUS Balance). It has advantages of high stiffness, low interference to flow field and six-components discrete. Development of the theories and technologies, design of the novel balance and verification by experiments were conducted and the main innovations are listed as follow:

1.           The investigation to present the aerodynamic measurement method of the novel balance. The theoretical solutions for the relationship of inner forces of rods and aerodynamics were obtained based on the static and dynamic equations. The solutions by solving the equilibrium equation of the three dimensional forces perform nice agreement with the results of experiment. The deviation between outer loads and the resultant forces was less than 2%. The multi-degree vibration equation was solved to obtain the dynamic solution, which laid a theoretical foundation for the dynamic force measurement in shock tunnel. The theoretical solution reveals that there is a one-to-one correspondence between the inner forces of the rods and the aerodynamics, that is, the matrix of coefficient has an exact theoretical solution. However, for the conventional balance, a mass of the calibration experiments should be conducted to obtain a proximate matrix of coefficients.

2.           A low-interference layout of the rods and balances was discussed from the perspective of the generalized modal matrix. It contained a perpendicular combination that included two planes and a sting support, which performed a holistic design form of balance. Theory for stiffness adjustment was investigated to provide rapid and simple equations for the layout design. Results showed that 5-6 parameters could give influence on the stiffness of the draw-rod system and it’s easier to change the stiffness of the system. The requirements of the low-interference layout and stiffness were chosen as constraint conditions to discuss the influence rules of items, such as positons and number of the planes to arrange the rods, numbers of rods in each plane, forms of sting support. As a requirement of the dynamic theory for the aerodynamic measurements, a one-station measurement method of spatial geometric parameters was developed. It’s essential for the high-accuracy aerodynamic measurement. In addition, an axial balance with capacities of self-equilibrium of inner forces was developed and manufactured to solve the large deformation during the preloading of the system. The HB2 standard aerodynamic model was applied in an actual shock tunnel experiments. For all the six components, 3~6 periods of the signals could be obtained. Compared with data of the national military standard, the derivation of the measured axial coefficient was 2% and the repeatability precision was less than 1.8%. Further study focused on the experimental study on engine-integrated aircraft model. And it aimed at the performance of the novel method when applied for the full-scale X-51A model. High stiffness and high accuracy were proved by the aerodynamic measurement results.

3.           The investigation on the interference induced by rods for the novel balance was conducted. The surface of the aircraft model was simplified as the infinite plate and the rods were simplified as semi-infinite cylinder. The typical flow fields were simulated by solving the three-dimensional Navier-Stokes equation. Further analysis focused on the magnitude of aerodynamics increment on the plate and the characters of the aerodynamic distribution on rods. Results showed that the interference induced by the single rod was less than 0.5% and the symmetrical arrangement of rods makes it lower than 0.05%. And the interference could be corrected.

4.           Investigation on the modelling method of the impulse force during the start-up process of the shock tunnel was performed. The evolution process of the wave structures was obtained. The frequency properties were analyzed by setting up analytical form of force. Moreover, the modelling of the impulse force was conducted. The theoretical form of the “energy metric” was derived based on the forced vibration properties of the force measurement system. Several harmonic forces (generally 3~5) were selected to model the impulse force and they contained the similar excited energy with impulse forces. A discussion was also conducted for the rules to design the balance based on properties of the impulse forces.

 

语种中文
文献类型学位论文
条目标识符http://dspace.imech.ac.cn/handle/311007/73135
专题高温气体动力学国家重点实验室
作者单位1.中国科学院力学研究所
2.中国科学院大学
推荐引用方式
GB/T 7714
孟宝清. 高超声速分立悬挂式气动力测量理论与技术[D]. 北京. 中国科学院大学,2018.
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