High-Speed X-ray Flow Visualization of a Liquid Jet

Liquid jets are found in many applications, from electronics cooling to manufacturing to cleaning. This study utilizes high intensity X-rays from the Advanced Photon Source (APS) at Argonne National Laboratory to visualize a water jet emanating from a 2.1 mm circular nozzle into an air region. Three X-ray visualization modes are employed to study the jet operating at three Reynolds numbers to cover laminar, transitional, and turbulent flow. Focused beam X-ray measurements use a 5 x 6 micron monochromatic X-ray beam to determine the jet equivalent pathlength at selected locations. Data are acquired at 6.25 MHz so high-frequency fluctuations at the gas-liquid interface can be assessed. White beam X-ray imaging provides a high intensity polychromatic X-ray beam over a larger area that allows high-speed X-ray video of the entire jet region. Image acquisition rates up to 10 kHz are captured to provide qualitative images of the entire jet. Mono beam X-ray imaging uses a larger monochromatic X-ray beam than focused beam imaging, but the beam is at a lower flux than white beam imaging. Hence, instantaneous 2D projections of the equivalent path length over the entire jet width are possible, but at slower acquisition rates than white beam imaging.