Experimental Studies and Cfd Calculations for Buoyancy Driven Mixing Phenomena
نویسندگان
چکیده
Buoyancy driven flow is found in many engineering application such as the mixing of fluids with different densities. In nuclear reactor safety the mixing of borated and deborated water is a critical issue that needs investigation, assessment and prediction. As nuclear reactor geometries are complex, in this study a simple vertical mixing test facility (VeMix) was used to validate numerical models. Through the application of defined initial conditions in the test facility the mixing process could also be predicted by CFD simulations performed with ANSYS CFX software. A newly developed planar sensor was applied to experimentally investigate the mixing process. The sensor yields images of fluid distribution over the sensor’s surface by individually interrogating the conductivity of a multitude of sensing structures. Furthermore, an image processing algorithm based on the optical flow concept was implemented and tested which allows the measurement of flow pattern velocities. Validation experiments were performed in the VeMix test facility which show typical vertical and horizontal flow pattern under different flow regimes. The data from the planar sensor of mixing process and velocity fields were used for the validation of the simulation results. Comparisons of the experimental results with the corresponding simulations show similar flow patterns and typical periodic behavior.
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