亚跨超风洞现代试验设计方法研究

开展了基于现代试验设计方法(MDOE)的亚跨超风洞试验研究,以八号标模尾翼为试验对象研究其气动特性,采用同时改变攻角-侧滑角的多变量方法,而不是传统的单变量(OFAT)方法进行试验。对自变量攻角和侧滑角进行试验设计(DOE),应用响应面法建模,用IV-最优方法对测量点分布进行设计。在FD-12亚跨超风洞完成了试验,并和传统的OFAT方法结果进行比较分析。结果表明:MDOE方法获得的数据和传统的OFAT方法的数据吻合很好;MDOE采集样点数减少了46%,吹风的时间比OFAT减少30%左右,提高了风洞试验效率,缩短了试验周期;MDOE试验方法可以给出设计空间内任意给定自变量对应的响应值及其置信区间。     

基于现代试验设计的风洞天平校准方法

风洞天平的校准精度直接决定了风洞试验的气动载荷测量精度,为了提升天平校准的质量和效率,以BCS-100天平校准系统为研究对象,基于现代试验设计方法（modern design of experiments,MDOE）开展了风洞天平校准研究。针对单因子变量法（one factor at a time,OFAT）天平校准中存在系统误差与响应量耦合的问题,采用MDOE的随机、重复和分块策略控制校准的系统误差,并选定响应面理论的中心复合设计方法生成校准矩阵。校准矩阵共计86个样本点,包括64个分级因子点、12个轴向因子点和10个中心因子点,其中所有样本点的加载顺序做随机化处理,并作为一个样本块在短时间内集中完成加载,中心因子点则用于满足重复原则。最后开展了OFAT和MDOE的对比校准,拟合载荷的残差正态概率分布显示MDOE校准中横侧向分量的样本点独立性更强,样本点残差最高可降低84%;检验载荷显示MDOE和OFAT两种方法中天平所有分量的综合加载重复性持平,MDOE校准中横侧向分量的综合加载误差最高可降低54%。研究表明MDOE能够有效降低校准的系统误差,提升横侧向小量的预测能力。     

基于神经网络-遗传算法的液力透平叶片型线优化

提出了一种叶片型线的多工况优化设计方法,该方法包括叶片型线参数化、优化的拉丁超立方试验设计、CFD技术、GA-BP(genetic algorithm-back propagation)神经网络与遗传算法.具体采用三次非均匀B样条曲线参数化叶片型线,优化的拉丁超立方试验设计方法在设计空间内获取训练GA-BP神经网络的样本点,各个样本点性能分析由CFD技术完成,随后开展GA-BP神经网络的学习训练,最后采用GA-BP神经网络和遗传算法相结合的优化技术求解液力透平叶片型线的多工况优化问题.基于上述优化方法对一液力透平进行了叶片型线的优化改进,结果表明,在保证扬程不小于相应初始扬程的约束条件下,优化后的液力透平效率在3个指定工况下分别提高了3.91%,3.59%和3.09%, 证明采用此方法优化叶片型线具有一定的可行性.      

气动模型在现代气动试验设计中的应用研究

简要比较分析了MDOE方法相对于传统OFAT方法的优势,研究了MDOE方法的关键影响因素。研究表明气动模型是现代试验设计的关键因素之一,提出基于气动模型的试验设计新方法。为此,文章研究了一类带电缆罩的轴对称飞行器的气动数学模型,并以三角级数的形式给出了模型的通用形式。以某飞行器为对象,以饱和D-最优为准则,分别采用三角级数模型和常用的响应面模型,开展了气动模型对现代试验设计的影响研究,验证了气动数学模型在现代试验设计中的重要作用以及试验设计新方法的有效性,获得了有价值的研究结果。     

基于Kriging模型的风洞应变天平静态校准方法

本文提出了一种基于Kriging代理模型的风洞应变天平静态校准方法。采用拉丁超立方设计的试验设计（DOE）方法选取校准加载点,以六分量组合加载技术为支撑,采用一阶回归基函数和EXP关联函数对校准数据构建Kriging模型,以电压信号增量和其他条件变量为自变量,通过Kriging模型对天平所受载荷进行预测。校准结果表明,与传统的OFAT（One Factor at A Time）校准方法相比,该方法具有相同的准度,加载点数量极大减少。将该方法应用于某矢量喷管推力测量天平的校准工作中,以通气流量和天平电压信号增量作为自变量,较好预测了喷管产生的推力,解决了传统校准方法难以克服的通气影响问题。     

基于多输出高斯过程的超临界翼型优化

提出了一种基于多输出高斯过程(MOGP)回归模型和模拟退火算法相结合的翼型优化方法。采用拉丁超立方抽样方法在设计空间内构造一系列样本点,其中优化设计采用CST参数化方法对翼型的几何外形进行参数化表示。通过CFD流体计算得到其响应值来建立初始的MOGP代理模型。以阻力最小化为设计目标,考虑面积、升力等约束条件。通过单点优化和多点优化试验表明,发展的翼型优化设计方法达到了优化设计的目的,同时也说明基于MOGP模型的优化设计方法在气动优化设计中的应用是可行的。     

Kriging模型在固体火箭发动机装药可靠性分析中的应用

基于Kriging方法对固体火箭发动机装药结构可靠性进行了分析.首先,采用拉丁超立方抽样技术得到了随机参数样本点;然后,利用样本点数据对黏弹性有限元模型的装药进行了结构力学分析;最后,通过Kriging模型得到了八面体剪应变的函数近似响应面,并结合失效判据对失效函数进行了可靠性计算.为了验证Kriging模型在可靠性计算中的有效性,其计算结果与Monte-Carlo方法进行了比较,得到了十分接近的可靠度.      

基于Kriging模型的翼型多目标气动优化设计研究

在翼型气动优化设计中引入Kriging代理模型,发展了一套高效、稳定的气动优化设计程序。采用拉丁超立方试验设计方法在设计空间内构造一系列样本点,通过求解二维可压缩的雷诺平均NS方程（RANS）得到其响应值来建立初始Kriging模型。优化设计采用Hicks-henne函数对翼型几何外形进行参数化表示,以阻力极小化为设计目标,考虑面积、升力、力矩等约束条件,通过算例证明,发展的优化设计方法不仅可行,而且具有高效稳定的特性。与传统的优化设计方法比较,大大减少了设计时间。     

现代试验设计方法在高速风洞试验中的应用

为了验证现代试验设计(MDOE)方法在高速风洞试验中应用的可行性,进一步提高风洞试验效率,采用区组化的回归组合设计进行了某运输类飞机亚声速基本纵向常规测力风洞试验,通过少量关键控制点数据建立了气动力参数随马赫数和迎角变化的二阶响应面模型,并进行了方差分析及显著性检验。同时,通过额外增加的试验点检验响应面模型的精准度。试验及分析结果表明:通过回归组合设计少量试验点建立的纵向气动力系数响应面模型预测误差满足高速风洞飞机模型测力试验精度指标要求,方差分析(ANOVA)及显著性检验结果正确反映了迎角、马赫数对飞行器基本气动特性的影响规律,突显出MDOE方法应用于风洞试验方案设计及数据分析的显著优势。     

基于 Kriging模型机翼平面外形气动优化设计

使用基于Kriging模型的优化设计方法,进行了非常规布局机翼的平面外形多目标优化设计。利用CFD技术进行机翼升力系数和阻力系数的气动计算,通过拉丁超立方试验设计生成样本点,建立了Kriging代理模型,结合多目标遗传算法对机翼平面外形进行多点多目标优化设计,最终得到了Pareto最优解集。根据设计需求,从Pa-ret0前沿选取一个非劣解作为优化结果。结果表明：陆ging模型与cFD计算误差很小,可信度高;在不问设计状态下,机翼气动性能都得到了提高,表明优化设计方法具有可行性和高效性。     

某型倾转旋翼机的旋翼桨叶气动优化设计

倾转旋翼机的旋翼气动外形设计需要对其直升机模式和固定翼模式下的不同要求进行综合考虑。通过基于Kriging模型的多目标遗传算法建立一套适用于倾转旋翼桨叶气动外形优化设计方法,采用拉丁超立方抽样试验设计方法得到样本点,并建立Kriging模型替代费时的流动数值模拟。以最大化旋翼地面悬停拉力和高空巡航效率为目标,以地面悬停功率不增和巡航拉力不减为约束条件,进行倾转旋翼桨叶平面形状优化设计,并经过非定常数值模拟和风洞试验验证。结果表明:数值模拟结果和风洞试验结果吻合良好,优化结果满足设计指标。     

代理模型选样准则研究

致力于针对确定问题,利用其在已知空间中的样本信息指导该问题其他空间中的样本选择.基于Kriging模型和拉丁超立方设计选样方法,以某数学函数为例,首先研究了设计空间大小对样本选择的影响,然后具体分析了样本分布特性对代理模型预测误差的影响.引入了样本平均疏密度、样本稀疏度、样本紧凑度等概念衡量样本特性,依据不同空间中各参数与代理模型预测精度的关系提出了样本稀疏度准则,并以不同维数的数学函数和翼型气动力分析模型验证了准则的准确性和实用性.     

Multi-disciplinary design optimization with fuzzy uncertainties and its application in hybrid rocket motor powered launch vehicle

In this paper, an Uncertainty-based Multi-disciplinary Design Optimization (UMDO) method combining with fuzzy theory and Multi-Discipline Feasible (MDF) method is developed for the conceptual design of a Hybrid Rocket Motor (HRM) powered Launch Vehicle (LV). In the method proposed, membership functions are used to represent the uncertain factors, the fuzzy statistical experiment is introduced to analyze the propagation of uncertainties, and means, standard deviations and credibility measures are used to delineate uncertain responses. A geometric programming problem is solved to verify the feasibility of the Fuzzy-based Multi-Discipline Feasible (F-MDF) method. A multi-disciplinary analysis of a three-stage HRM powered LV involving the disciplines of propulsion, structure, aerodynamics and trajectory is implemented, and the mathematical models corresponding to the F-MDF method and the MDF method are established. A two-phase optimization method is proposed for multi-disciplinary design optimization of the LV, including the orbital capacity optimization phase based on the Ziolkowski formula, and the scheme trajectory verification phase based on the 3-degree-of-freedom point trajectory simulation. The correlation coefficients and the quadratic Response Surface Method (RSM) based on Latin Hypercube Sampling (LHS) are adopted for sensitive analysis of uncertain factors, and the Multi-Island Genetic Algorithm (MIGA) is adopted as the optimization algorithm. The results show that the F-MDF method is applicable in LV conceptual design, and the design with the F-MDF method is more reliable and robust than that with the MDF method.     

2．4m跨声速风洞的模型位移视频测量精度研究

风洞试验中模型的位置和变形测量对试验数据精准度至关重要。为此,创建2．4m跨声速风洞的模型位移视频测量系统,提出度量其测量误差的方法,并实验研究其测量精度。研究发现,试验中的振动对测量精度影响极大,采用振动环境中相机位、姿解算方法后,试验段底部的编码标记点的测量误差从22．80-48．48mm降至0．03～0．64mm。     

风洞收缩段曲线气动性能研究

介绍了一种新的风洞收缩段曲线的设计方法,即UG参数化收缩段壁型曲线设计。采用商用软件fluent对这种收缩段曲线性能进行数值模拟计算,获得了好的流场品质,对于风洞的设计以及流动优化提供了新的设计思想。在模拟计算的基础上应用了该研究成果加工制造了一座低速风洞,并对风洞流场进行了校测,对比了模拟计算结果与实验测量结果,并进行了流场性能分析。该设计方法可以应用推广到风洞设计工作中去。     

Scaling procedures of cabin noise generated by turbulent boundary layer excitation

This paper presents a new method for measuring the cabin noise of a structure in a wind tunnel. A method for scaling the cabin sound was derived to obtain the cabin noise of a structure, and the derivation of the scaling procedure was based on a theoretical hypothesis regarding the cabin noise prediction for a scaled model in a wind tunnel. A frequency offset was generated because of the error introduced by model manufacture and installation, and a proposed modal test method was used to eliminate the frequency offset. Both a full-scale structure and scaled structure were measured in the wind tunnel tests. The cabin noise of the full-scale model was compared with the results obtained using the scaling procedure based on the scaled model. The comparisons of the measurement results indicate that the scaling procedures developed in this paper are effective for vibro-acoustic predictions in wind tunnels. Moreover, background noise tended to affect the results of the cabin sound for the wind tunnel test, and thus background noise should be prevented through specific design efforts.     

天平与波纹管系统结构设计与有限元分析

为满足某飞机后机身风洞试验需求,研制了一种用金属波纹管密封测力天平的新型测力装置。利用密封原理,该装置的波纹管结构能有效地隔断风洞流场压力波动,使其内腔压力平衡,确保天平精确测量作用在飞机后机身上的气动载荷。通过对天平与波纹管系统进行合理的结构设计,以及应用有限元方法进行详尽的静态和动态力学分析,该装置得到了较为理想的设计结果。天平地面校准和风洞试验结果表明,波纹管密封效果好,对天平测力干扰小,达到了预期的试验要求。     

An active damping vibration control system for wind tunnel models

In wind tunnels, long cantilever sting support systems with low structural damping encounter flow separation and turbulence during wind tunnel tests, which results in destructive low-frequency and big-amplitude resonance, leading to data quality degradation and test envelope limitation. To ensure planed test envelope and obtain high-quality data, an active damping vibration control system independent of balance signal based on stackable piezoelectric actuators and velocity feedback using accelerometer, is proposed to improve the support stability and wind tunnel testing safety in transonic wind tunnel. Meanwhile, a design of powerful sting-root embedded active damping device is given and an active vibration control method is presented based on the mechanism analysis of aircraft model vibration. Furthermore, a self-adaptive fuzzy Proportion Differentiation(PD) control model is proposed to realize control parameters adjustment automatically for various testing conditions. Besides, verification tests are performed in laboratory and a continuous transonic wind tunnel. Experimental results indicate that the aircraft model does not vibrate obviously from -4° to 11° at Ma = 0.6, the number of useable angle-of-attack has increased by 7° at Ma = 0.6 and 5° at Ma = 0.7 respectively, satisfying the requirements of practical wind tunnel tests.     

FERA in parameter identification with application in low speed wind tunnel test

This paper presents a new approach which consists of a fuzzified eigensystem realization algorithm (FERA) to identify the parameters of the designed mini-UAV model performance in the low speed wind tunnel (LSWT) power on testing system. On the basis of the identification scheme, it is able to reduce system operational cost of wind tunnel tests and provide a tool for predicting results without resorting to on-site experiments. A variety of variables in model types and testing environment such as model profile, angle of attack, elevator, tunnel wind speed and power system (motor and propeller) are considered. The method based on logic devices is simple yet effective. The results obtained are compared to those obtained by the conventional wind-tunnel testing method. To verify effectiveness of the proposed methodology, both of simulations and real-world experiments are conducted. The results show that the working performance of the proposed method correlates well with expectation.