Study on Two-Phase Flow in Small Metal Pipe Tube using Proton Radiography

研制了一种高灵敏度、高分辨率的实时质子照相系统，当以不透明流体为工质，测试截面为金属时，不能用光学方法对沸腾气泡进行可视化。由于高速事件，如沸腾气泡的行为，它已经很难用X射线或中子束可视化。在这些情况下，可以预期质子照相是有用。由于质子射线照相依赖于质子的电离功率在其射程末端附近随距离的快速变化，因此用于高通量的质子束。本文采用14 Mev单色质子束，用质子照相技术对细小金属管内沸腾气泡等动态事件进行了可视化研究。用直径分别为0.94 mm、1.54 mm和1.94 mm的质子束流密度约为10~(-11)粒子/cm~(-2)s照射试验段，然后在靠近试验段的荧光屏上拍摄沸腾气泡的质子照相。用高速摄像机记录的气泡图像(最大每秒4000帧)。

High sensitive and high resolution real-time proton radiography system has been developed.When an opaque fluid is used as a working fluid and the test section is made of metal, optical method cannot be used for the visualization of the boiling bubbles. It has been difficult to visualize with X-ray or neutron beams because of the high speed events such as behaviors of boiling bubbles. In these case, it may be expected that proton radiography is useful. Because proton radiography depends on the rapid change of ionizing power of proton with distance near the end of their range and is used with a high flux of proton beams. In this study, the visualization of the dynamic events such as boiling bubbles in a small metal pipe was investigated by using proton radiography.The monochromatic proton beam of 14 Mev was used. Test section were irradiated with proton beam flux of about 10^<11> particles/cm^2.s for 0.94, 1.54 and 1.94mm in diameter, and then proton radiography of boiling bubbles were taken on the fluorescent screen near by the test section. Images of bubbles recorded with the high speed video camera (maximum 4000 frames per second).