Application of tomographic reconstruction techniques to quantify multiphase flows during sloshing model tests

Abstract

Sloshing in partially filled tanks induces dynamic loads on tank walls and structures inside the tank. Internal structures influence the flow and may lead to ventilation effects that generate a gas-liquid mixture. Entrapped and dissolved gas alters the properties of the liquid phase, which typically reduces impact loads. In the present study, non-invasive tomographic reconstruction techniques were applied to optically capture entrapped air in a sloshing model-scale tank. The simultaneous multiplicative algebraic reconstruction technique (SMART) and the multiplicative line-of-sight (MLOS) technique were used to quantify entrapped air. Results showed that the accuracy of the calculated air volumes depends significantly on the image pre-processing as well as on the selected reconstruction settings. A predefined test case was used to adjust the processing and to validate the reconstruction results. Induced single bubbles were captured while the tank oscillated, exciting the fluid in resonance. Associated trajectories of the rising bubbles were captured, compared, and analyzed. The applied tomographic techniques were capable to reconstruct the required volume of interest for single bubbles and bubble clouds. Tank motions did not limit measurement capabilities as the camera setup moved along with tank motions.