Erosional jets, the ultimate challenge in coupled flow-particle dynamics: Application to industrial post operational clean out

点击翻译按钮获取中文摘要

Impinging jets are used in a wide range of process engineering applications, such as tunnelling operations, paint spraying and cavitation drilling. Liquid jets are also used as a method to estimate sediment strength in natural environment studies. They are additionally important within the nuclear waste industry for mixing of radioactive wastes, as they are preferred over mechanical impellers, due to the lack of moving parts. Despite this wide relevance of multiphase jet mixing systems, quantitative studies of their flow-profiles, turbulence and recirculation in sediment beds are lacking, while current predictions of erosion thresholds are also empirical. Difficulties arise in characterisation, due to the complex impingement profiles and because traditional laser or image techniques cannot be used at high solids loads. As an alternative, this PhD project will seek new research to investigate the application of acoustic Doppler and backscatter instruments to characterise these complex flows and their erosion profiles. Measurements will be coupled with multiphase CFD simulations of the jets, to specifically enable the prediction of impinging jet mixers used to mobilise nuclear wastes, as part of post operational clean out (POCO) operations at Sellafield Ltd.