ENDGAME - Laboratory Experiment 2024-01-18 Exp. 008 - High Speed Camera data

Shock-tube experiments in combination with high speed Schlieren shadow photography. 

The shocktube setup consists of a high-pressure reservoir connected with a cylindrical tube through a diaphragm pulse valve which allows a fast release of pressurized gas into the ambient pressure tube. The high-pressure reservoir is filled with compressed air at a given overpressure with respect to ambient pressure (up to 8 bar). The pipe was either empty (i.e. with air at ambient conditions) or filled with a given amount of small particles. We adopted pipes an inner diameter of 4 cm and different lengths (20, 30 and 80 cm). We also considered different volumes of pressurized gas (~650 cm3 and ~1550 cm3). A pressure sensor has been placed at the vent of the conduit to record pressure variations during experiments. Images from the high speed camera were collected at a frame rate of 30000 fps.

When the valve is open, a jet flow is produced, with shock and acoustic waves propagating in the atmosphere, which become visible due to the high speed Schlieren shadow photography.

本数据集采用激波管（shock-tube）实验结合高速纹影阴影摄影（Schlieren shadow photography）技术开展数据采集。

激波管实验装置由高压储气腔与圆柱形实验管组成，二者通过膜片脉冲阀相连，该阀可实现高压气体快速释放入常压实验管中。高压储气腔填充的压缩空气相对于环境压力具有设定过压值，最高可达8巴。实验管可保持空置（即填充环境条件下的空气），或充入定量细小颗粒。本次实验所用实验管内径为4厘米，长度分别为20、30与80厘米；同时设置了两种不同容积的高压储气腔，对应气体容积约为650立方厘米与1550立方厘米。在管路排气口处安装有压力传感器，用于记录实验过程中的压力变化。高速相机以30000帧每秒的帧率采集图像数据。

当膜片脉冲阀开启时，会产生射流，同时伴随激波与声波在大气中传播，这些流动现象可通过高速纹影阴影摄影技术清晰显现。