Evaluation of 3D mapping experimental non-intrusive methods for multiphase flows

Abstract

The present contribution focuses on the evaluation of non-intrusive 3D mapping experimental methods for the investigation of multiphase flows during tank sloshing. This problem is a key issue for launchers and satellites since the feeding in propellants has to be ensured during flight and manoeuvres. At first, an extensive survey of non-intrusive experimental techniques of interest for multiphase flows has been carried out. This task has accounted for new innovative methods developed for space and non-space applications with a focus on the methods used in medicine and other fields such as ultrasound techniques. A particular care has been given to electrical and ultrasonic tomography techniques since they are both non-intrusive, non-invasive, low cost, fast and simple to operate, and suitable for real time measurements. Electrical tomography techniques have demonstrated convincing capabilities for multiphase flow visualization and present numerous advantages for industrial processes and multiphase flow measurements. Ultrasound experimental techniques are extensively used in medicine for a wide range of investigations. They are also largely used for material analysis and fluid mechanics. As a consequence since several years, ultrasound tomography has been applied to multiphase flows. Application of the method to annular, sludge, slug and bubbly flows has demonstrated the potential of this technique for multiphase flow investigations. Additionally, in the context of launchers this technique presents an advantage in term of safety. Using the available results, the advantages and disadvantages of ultrasonic and electrical methods have been identified and this leads to the conclusion that the ultrasonic tomography possesses the best potential for the final application. Finally, using the available experimental results obtained using ultrasound tomography for the mapping of multiphase flows, numerical simulations have been performed to proceed to their reconstruction. This provides a cross-check between the experimental data and the numerical predictions in order to assess the suitability of the techniques for future studies.