A High-Speed X-Ray Detector System for Noninvasive Fluid Flow Measurements

The opaque nature of many multiphase flows has long posed a significant challenge to the visualization and measurement of desired characteristics. To overcome this difficulty, X-ray imaging, both in the form of radiography and computed tomography, has been used successfully to quantify various multiphase flow phenomena. However, the relatively low temporal resolution of typical X-ray systems limit their use to moderately slow flows and time-average values. This paper discusses the development of an X-ray detection system capable of high-speed radiographic imaging that can be used to visualize multiphase flows. Details of the hardware will be given and then applied to sample multiphase flows in which X-ray radiographic images of up to 1,000 frames per second were realized. The sample flows address two different multiphase flow arrangements. The first is a gas-liquid system representative of a small bubble column. The second is a gas-solid system typically found in a fluidized bed operation. Sample images are presented and potential challenges and solutions are discussed.