L3:THM.CFD.P9.05 Full-Field Measurements of Turbulent Bubby Flow using Innovative Experimental Techniques

Multi-phase flows are one of the challenges on which the CFD simulation community has been working extensively with a relatively low success. The phenomena associated behind the momentum and heat transfer mechanisms associated to multi-phase flows are highly complex requiring resolving simultaneously for multiple scales on time and space. Part of the reasons behind the low predictive capability of CFD when studying multi-phase flows, is the scarcity of CFD-grade experimental data for validation. The complexity of the phenomena and its sensitivity to small sources of perturbations makes its measurements a difficult task. Non-intrusive and innovative measuring techniques are required to accurately measure multi-phase flow parameters while at the same time satisfying the high resolution required to validate CFD simulations. In this context, this work presents the implementation of innovative measuring techniques that can provide whole-field and multi-scale measurements of twophase flow turbulence parameters. To this end, simultaneous implementation of visualization techniques are used to study isothermal two-phase turbulent flows through a vertical rectangular channel. These techniques are listed next and are used as follow: 1) Particle Tracking Velocimetry (PTV) is used to analyze the influence that the diluted phase parameters have on the liquid phase turbulence statistics, and 2) High-speed shadowgraphy with LED illumination is used to obtain the gas phase dynamics. The present experiments are intended to improve the understanding of two-phase turbulent flows and to provide reliable and accurate experimental information for verification and validation of two-phase flow computational models. In this report, isothermal bubbly turbulent flow in a square channel was studied. The experiments were performed with two different gases diluted in liquid refrigerant (3M-7000). Helium and nitrogen were used as the dispersed phase. The gas was injected into the channel through a porous media at three different superficial gas velocities. For helium, the gas superficial velocities were: 0.81 mm/s, 3.85 mm/s, 7.33 mm/s. And for nitrogen, the gas superficial velocity was 5.50 mm/s, 9.17 mm/s, 16.5 mm/s. Measurements of the liquid parameters CASL-U-2014-0209-000 L3:THM.CLS.P9.05 such as the velocity, RMS of the liquid velocity, and Reynolds stresses were provided by PTV. The availability of simultaneous shadowgraphy and PTV experiments allowed the study of the intricate interaction between the liquid and gas phases. The present experiments were designed to provide information for the development and validation of two phase flow turbulence models.