The atomization and vaporization of liquid jets within turbulent gaseous flows are characterized by the mixing phenomena occurring over a wide range of spatiotemporal scales. This creates a complex, turbid medium that is not easily interrogated using conventional optical-measurement techniques. In the current work, the optically dense, multiphase flow created by a cryogenic liquid jet injected into a turbulent gaseous coflow is probed using high-speed (MHz) X-ray radiography from a focused, narrowband synchrotron source to resolve the internal cascade of scales and the evolution to isotropic, homogeneous turbulence. Changes in the spectral characteristics for different flow conditions are furthermore correlated with changes in the spatial distributions of the liquid and gas phases within the spray using simultaneous X-ray radiography and tracer (krypton) fluorescence. It is found that an increase in entrainment and mixing infers an evolution in spectral characteristics toward the well-known −5/3 law of energy dissipation in the context of the classical Kolmogorov theory. These data demonstrate the utility of the synchrotron-based X-ray radiography and fluorescence for uncovering the internal, turbulent mixing processes in multiphase and optically dense flows.
Synchrotron X-Ray Interrogation of Turbulent Gas–Liquid Mixing in Cryogenic Rocket Sprays
2017
Article (Journal)
English
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