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，适用于具有高度复杂运动几何形状的强非线性的潜在暴力自由表面流体力学。本文所开展的研究将适用于水工建筑物的核退役流和核工业的产热流。该项目将解决以下重要问题：在预测结果流体动力学的背景下，确定复杂混合物建模的最佳技术，确定不同机制的影响，应用于涉及文献中可用的沉积物数据的测试案例，以及英国国家核实验室（NNL）提供的案例。更具体的细节：高活性液体（HAL）是在乏核燃料后处理过程中产生的。由此产生的废物流具有腐蚀性，化学成分复杂，并产生热量。它包括两个主要阶段：液体层和粘性沉积物，沉积物包含了大部分的活动，并通过放射性衰变产生热量。在玻璃化之前，废物流被储存在大罐中；废物定期搅拌，以避免形成局部热点，否则会增强腐蚀并减少设施的使用寿命。博士课程将重点研究储罐内搅拌系统中复杂混合物的模拟。这种复杂的多相问题不是传统的现代技术所能解决的，因为传统技术很难捕捉到液体/沉积物界面。这项工作将建立在之前的博士项目的基础上，该项目于2014年完成（Fourtakas），利用开源代码dualspphysics: http://www.dual.sphysics.org中图形处理单元（gpu）提供的加速开发新的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