阵风发生器是阵风响应风洞试验的关键设备.针对叶片式阵风发生器的运行特点,通过简化的定常涡升理论,推导出阵风发生器下游流场Y向风速的计算公式.以0.55?m×0.4?m低速风洞(声学引导风洞)为实验平台,系统地研究了阵风发生器的设计参数(叶片弦长、数目、间距)和运行参数(叶片摆幅和摆动频率、来流速度)对阵风流场风速极值的影响.研究表明:推导的简化公式能够解释阵风发生器各设计和运行参数变化后,其下游流场Y向风速的变化机制,可在阵风发生器设计时对其产生的阵风流场进行简单预估;从增大阵风发生器下游流场Y向速度极值的角度出发,增加叶片数目比增大叶片弦长更能增大Y向速度;在叶片失速前,增大叶片摆幅比增大叶片摆动频率更能增大Y向速度;采用多组叶片的阵风发生器,叶片间距不能太小,否则会导致等效升力系数下降,当叶片间距为1.2倍弦长时,能够获得最大的Y向速度极值.本文研究工作可为其他风洞的阵风发生器设计提供参考.

为满足型号试验需求,2.4 m×2.4 m跨声速风洞需在不改变现有洞体结构和安装条件下新研制一个截面尺寸为3 m×1.92 m(宽×高)的专用开孔壁试验段.为了降低技术风险和投资风险,以0.24 m×0.20 m跨声速风洞(2.4 m×2.4 m跨声速风洞的引导风洞)为实验平台,采用变截面气动设计方案新设计、加工了一个专用开孔壁试验段实验件,并开展了预先性实验研究工作.通过实验研究验证了专用开孔壁试验段气动设计方案可行,且试验段模型区内流场达到设计指标要求.实验还考察了壁板扩开角、主流引射缝开度、开孔率分布等参数对流场均匀性的影响,研究结果表明:在扩开角0.3°、引射缝开度12 mm、加速区采用递增方式开孔时,专用开孔壁试验段的流场能够满足马赫数均方根偏差σM≤0.01(0.4≤Ma<1.0)、σM≤0.02(1.0≤Ma≤1.2、1.4)设计指标要求,并且在Ma≤1.0时,σM达到了国军标合格指标要求.研究工作为2.4 m×2.4 m跨声速风洞专用开孔壁试验段设计提供了技术支持,也为该风洞下一阶段调试和流场校测提供了可供参考的调试参数.

A pilot gust generator is as experiment object,by measuring the flow field of the gust generator in different situations with two dimension hot wire anemometer,the measurement scheme and online measuring angle correction,and the calculation of the gust amplitude and flow fluctuation are proposed.Experiment results show that online angle correction used can improve the accuracy and efficiency of two dimension hot wire in Y direction,phase analysis used can sat-isfy the calculate the amplitude and fluctuation of periodic gust.Gust amplitude is in direct ratio with the vane oscillation frequency of 4 ~ 15Hz,oscillation angle of 8°~ 30°,and vane chord length of 50~100mm.Unstability (velocity fluctuation at same phase)of the gust flow has a cer-tain linear relationship with the vane oscillation angle and wind speed,which increases while the vane oscillation angle and wind speed increase in the test range,at the same time,proper vane os-cillation frequency can decrease unstability.The conclusion is helpful for the gust generator de-velopment and flow field measurement in wind tunnel.

The flow field related to the interior weapons bay of a combat aircraft is associated with strong unsteadiness effects in the transonic range.The perforated test section of a 2.4 m×2.4 m injection driven transonic wind tunnel,whose test section caliber is China's only one larger than 2 m,is redesigned so as to obtain more accurate experimental data.Striving for the best design,attempts are made using computational fluid dynamics(CFD) analysis to evaluate and optimize the preliminary design project of a pilot wind tunnel.The boundary conditions of the perforated test section wall are validated by comparing with the experiment results at Mach number Mat=1.4,and then used for simulations of several projects.The current research reveales that the flow characteristics are greatly influenced by the entrance transition section and outlet transition section.The contraction and expansion of the entrance debase flow quality.The attitude of the injection flaps determines the size of the separation area.Then different models using different open-area ratios of perforated wall at entrance are investigated based on the numerical results.Desired flow quality is obtained when the transition section adoptes reasonable open-area ratios.

通过实验研究证明了用主流阻尼器快速调节半开口直流式低速风洞的实验风速的可行性.实验还考察了驻室容积、风扇转速等因素对调速加速度的影响,为稳态扫描环境模拟试验装置快速变速系统提供了必要的设计参数.