SPH For Multiphase Flows Inside a HAL Storage Tank

该项目将使用平滑粒子流体力学(SPH)，这是一种创新的无网格计算技术，非常适合于具有高度复杂运动几何形状的强烈非线性的自由表面流体动力学。本文开展的研究将适用于水工建筑物中的核退役流动和核工业中的产热流动。该项目将解决以下重要问题：在预测所产生的流体动力学的背景下，确定对复杂混合物进行建模的最佳技术；确定不同机制的影响；适用于涉及文献中可获得的沉积物数据的测试案例以及英国国家核实验室提供的案例。更具体的细节：高活性液体(HAL)是在乏核燃料的后处理过程中产生的。由此产生的废流具有腐蚀性，化学成分复杂，并会产生热量。它包括两个主要阶段：液层和粘性沉积物，沉积物包含大部分活动并通过放射性衰变产生热量。在玻璃化之前，废液被储存在大型储罐中；废物定期搅拌，以避免形成局部热点，否则会加剧腐蚀并缩短设施的运行寿命。PHD将专注于模拟储罐内搅拌系统中的复杂混合物。这种复杂的多相问题不适用于传统的现代技术，因为传统的现代技术难以捕捉液体/沉积物界面。这项工作将建立在2014年完成的前一个博士项目(Fourtakas)的基础上，该项目使用开放源代码DualSPHycitical：http://www.dual.sphysics.org中的图形处理单元(GPU)提供的加速来开发新的SPH配方

This project is to use Smoothed Particle Hydrodynamics (SPH), an innovative meshless computational technique ideal for potentially violent free-surface hydrodynamics where there is strong nonlinearity with highly complex moving geometries. The research developed here will be applicable to flows in nuclear decommissioning in hydraulic structures and the heat-generating flows in the nuclear industry. The project will address the important issues of identifying the best techniques for modelling complex mixtures in the context of predicting the resultant hydrodynamics, identify effects of different mechanisms, apply to test cases involving data on deposits available in the literature and for cases provided by National Nuclear Laboratory (NNL) in the UK. More specific detail: Highly active liquor (HAL) is generated during the reprocessing of spent nuclear fuel. The resulting waste stream is corrosive, chemically complex and heat-generating. It comprises two main phases: a liquid layer and a viscous sediment, the sediment contains the majority of the activity and generates heat via radioactive decay. Prior to vitrification, the waste stream is stored in large tanks; the waste is agitated regularly to avoid the formation of local hot-spots which would otherwise enhance corrosion and reduce the facility's operational lifetime. The PhD will focus on the simulation of the complex mixtures in the agitation systems within the storage tanks. This complex multi-phase problem is not amenable to traditional modern techniques, which struggle to capture the liquid/sediment interface. The work will build upon a previous PhD project, which was completed in 2014 (Fourtakas), developing new SPH formulations using the acceleration provided by graphics processing units (GPUs) in the open-source code DualSPHysics: http://www.dual.sphysics.org