Development of an Advanced PIV System for Full-Field Flow Measurement

研制了一种基于高速CMOS摄像机、高速脉冲激光器和定时控制器相结合的先进的动态PIV系统。通过添加另一台CMOS摄像机，用一对Scheinmpflug定位设备(自制)构建了一个立体PIV系统。该系统已应用于各种流场的全场流动测量，并利用现有的动态PIV系统对水滴射流进行了测量。用立体和动态PIV系统测量了旋转速度为1800rpm的PC冷却系统轴流风扇下游的流动。利用两个高速摄像机成功地研制了一个不仅在时间上而且在空间上具有大动态范围的新系统，并将其应用于自由射流。利用立体动态PIV的实验结果分析了从多孔喷嘴喷出的空气射流的湍流和涡系结构。和同步MeA-…技术建立了更多的喷雾液滴尺寸和三维速度分量的确定，开发了复杂活体模型的非侵入式立体标定技术，实现了高时空分辨率的非定常流动测量。采用动态PIV系统分析动脉模型内的脉动流动，该系统具有高度的不稳定性和三维复杂性，成功研制了扫描立体PIV系统，用于测量圆形射流和圆形冲击射流的三维速度和涡量分布，其中圆形射流的流动装置中安装了冲击平板。利用研制的动态PIV系统对圆形冲击水射流进行了时空测量。通过对获得的湍流量的评估，对测量结果进行了验证。对滞流区湍流结构的时空行为进行了分析，发现壁面附近出现了间歇性的高速流体团块，并伴随着横向涡旋结构的存在。较少

An advanced dynamic PIV system has been successfully developed based on the combination of a high-speed CMOS camera, a high-speed pulse laser, and a timing controller. Adding another CMOS camera, a stereoscopic PIV system has been constructed with a pair of Scheinmpflug positioning devices (made in-house). The system has been applied to various flow fields for the full-field flow measurement.The water-droplet jet flow has been measured using the present dynamic PIV system. The flow downstream an axial flow fan for PC cooling system, rotating at 1,800 rpm, has been measured using the stereoscopic and dynamic PIV system.A new system with high dynamic ranges not only in time but also in space has been developed successfully by using two high speed cameras, and it was applied to a free jet flow..Turbulent and vortex structure of air jets issuing from a multi-hole nozzle have been analyzed using experimental results obtained by stereoscopic dynamic-PIV. And the technique of simultaneous mea … More surements of size and 3D velocity components of spray droplets has been established.Non-invasive stereo calibration technique for complicated living body models had been developed and highly temporal and spatial resolution of unsteady flow measurement is enabled. The dynamic PIV system is applied to analyze pulsatile flow inside the arterial model, which has highly instability and 3-dimensional complexity.A scanning stereoscopic PIV has been developed in success and was applied to measure the three-dimensional velocity and vorticity distribution of the round jet and the round impinging jet, where an impinging flat plate was installed in the flow apparatus of the round jet. Stretching of vortices in the stagnation region was observed.The dynamic PIV system developed has been used for the spatio-temporal measurement of a circular impinging jet flow of water. The measurement has been verified through an evaluation of turbulence quantities obtained. Spatio-temperal behaviors of turbulent structures in the stagnation region are analyzed, showing intermittent appearance of high-speed fluid lumps near the wall and the associated presence of transverse vortical structures.The International Workshop on Dynamic PIV was hosted by the present project group. Less