Ultra-fast x-ray tomography for multi-phase flow interface dynamic studies
Ultra-fast x-ray tomography for multi-phase flow interface dynamic studies
复制标题
用于多相流界面动力学研究的超快 X 射线断层扫描
作者：
Masaki Misawa;Ion Tiseanu;H. Prasser;Naoki Ichikawa;Makoto Akai
本文介绍了一种快速扫描X射线层析成像装置的概念、硬件研制和垂直管内气液两相流的测量结果。该设备使用18个脉冲X射线源，以连续的顺序激活。以这种方式，在38ms内获得对象的18个独立投影的完整集合，即。e.测量速率约为每秒250帧。最后，为了评估快速X射线CT的测量能力，在流动回路中安装丝网传感器，并且两个系统同时针对相同的两相流操作。两个系统的横截面平均空隙率时间序列的比较表明，在大空隙率下段塞流具有足够的一致性，而快速CT低估了泡状流的空隙率，尤其是在低空隙率范围内。对于丝网传感器，段塞气泡界面的强迫变形被发现。进一步的硬件改进正在进行中，以实现更好的分辨率与快速X射线CT扫描仪。
Abstract The present paper describes the concept of a fast scanning Xray tomograph, the hardware development, and measurement results of gas-liquid two-phase flow in a vertical pipe. The device uses 18 pulsed X-ray sources activated in a successive order. In this way, a complete set of 18 independent projections of the object is obtained within 38 ms, i. e. the measuring rate is about 250 frames per second. Finally, to evaluate the measurement capability of the fast X-ray CT, a wire-mesh sensor was installed in the flow loop and both systems were operated for the same two-phase flow simultaneously. Comparison of the time series of the cross section averaged void fraction from both systems showed sufficient agreement for slug flow at large void fractions, while the fast CT underestimated the void fraction of bubbly flow especially in low void fraction range. For the wire-mesh sensor, coerced deformation of slug bubble interface was found. Further hardware improvement is in progress to achieve better resolution with the fast X-ray CT scanner.