Towards comprehensive multiphase flow modelling for nuclear reactor thermal hydraulics

核反应堆热工水力综合多相流建模

• 批准号: EP/S019871/1
• 负责人: Marco Colombo
• 金额: $ 44.01万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FS019871%2F1
• 关键词: Towards; comprehensive; multiphase; flow; modelling

In any nuclear reactor, ensuring that the nuclear fuel always remains properly cooled is the main achievement of the thermal hydraulic design, which thus has utmost impact on the safety and the performance of the plant. Often, this thermal hydraulic design and the plant safety assessment rely on computational models that, by providing a mathematical representation of the physical system, predict the fluid dynamic behaviour of the coolant and the rate of heat transfer in the system. In a nuclear plant, in normal operating conditions or in accident scenarios that require emergency cooling, this often requires solving gas-liquid multiphase flow problems. Unfortunately, although computational tools of any degree of complexity are now available, modelling and computation of gas-liquid multiphase flows is still mainly limited to well-defined flow conditions and/or entirely based on empiricism. The aim of this fellowship is to develop an advanced computational model that overcomes these limitations and goes well-beyond currently available capabilities. At the present time, different techniques reach good accuracy in distinct and well-defined flow conditions, but none has been successful in modelling the entire spectrum of gas-liquid multiphase flows without a priori knowledge of the flow regime. This strongly limits the applicability of available models to flows that are of industrial interest, since these rarely exhibit the same well-characterized and defined flow features. In this project, by means of novel numerical techniques, advanced modelling methods will be coupled in the same computational model and selectively applied based on suitability to the local flow conditions. This will ensure accuracy and unprecedented applicability to multiphase gas-liquid flows, avoiding limiting assumptions but at the same time unrealistic computational requirements.In the nuclear sector, such a model will provide leading edge modelling and simulation capabilities, underpinning improved operation of the current reactor fleet and design and assessment of future plants. Confident predictions will inform the reactor design and the assessment of safety limits, reducing empiricism and conservatism. In addition, the number of costly experiments will be limited to a smaller number of model-driven tests. Reactors that are safer and produce electricity at a cheaper price and with a reduced waste footprint will underpin Government's plan for between 16 GW and 75 GW of new nuclear generation capacity by 2050. This new capacity will be essential to ensure a secure, sustainable and low-carbon energy future to the UK and respect the legally binding commitment to reduce carbon emission by 2050 of at least 80% with respect to 1990.In addition, the work will have wider application outside the nuclear sector in the optimization of the design and operation of the numerous industrial equipment exploiting gas-liquid multiphase flows across all branches of engineering (e.g. enhanced mixing by bubbles in bubble columns, fluid dispersion and mass transfer in separation equipment, two/three phase flow streams in extraction, treatment and transportation of oil and gas). At the same time, the fine resolution of spatial and temporal scales as well as of the majority of the interfacial details will allow more fundamental studies to be made. These will shed new light on the many aspects of multiphase flows that still miss thorough understanding, which negatively affects the design and operation of multiphase equipment. The project will benefit from close collaboration with esteemed academics within the UK and overseas (Massachusetts Institute of Technology and North Carolina State University) and industrial leaders in the development of computational products for the nuclear industry and in the analysis and assessment of nuclear reactor thermal hydraulics (Siemens Industry Software Ltd and Frazer-Nash Consultancy).

在任何核反应堆中，确保核燃料始终保持适当的冷却是热工水力设计的主要成果，因此对核电站的安全和性能有着最大的影响。通常，这种热工水力设计和工厂安全评估依赖于计算模型，通过提供物理系统的数学表示，预测冷却剂的流体动力学行为和系统中的热传递速率。在核电站中，在正常运行条件下或在需要紧急冷却的事故场景中，这通常需要解决气液多相流问题。不幸的是，尽管现在已经有了各种复杂程度的计算工具，但气液多相流的建模和计算仍然主要限于明确定义的流动条件和/或完全基于经验主义。该奖学金的目的是开发一种先进的计算模型，以克服这些限制，并远远超出目前可用的能力。目前，不同的技术在不同的和定义明确的流动条件下都能达到很好的精度，但没有一种技术能够在不事先了解流型的情况下成功地模拟整个气液多相流的频谱。这极大地限制了现有模型对具有工业意义的流动的适用性，因为这些流动很少表现出同样良好的特征和定义的流动特征。在本项目中，将通过新的数值技术，将先进的模拟方法耦合到同一计算模型中，并根据对局部流动条件的适应性有选择地应用。这将确保多相气-液流的准确性和前所未有的适用性，避免限制假设，但同时也有不切实际的计算要求。在核能领域，这样的模型将提供前沿的建模和模拟能力，为改善当前反应堆机队的运行以及未来工厂的设计和评估奠定基础。自信的预测将为反应堆设计和安全极限评估提供信息，减少经验主义和保守主义。此外，昂贵的实验数量将被限制在较少数量的模型驱动测试中。更安全、以更低价格发电和减少浪费的反应堆将支持政府到2050年新增16千兆瓦至75千兆瓦核能发电能力的计划。这一新能力对于确保英国未来的安全、可持续和低碳能源至关重要，并遵守具有法律约束力的承诺，即到2050年将碳排放量减少至少80%。此外，这项工作将在核能部门以外的许多工业设备的优化设计和操作中得到更广泛的应用，这些设备利用跨越所有工程分支的气液多相流(例如，鼓泡塔中的气泡强化混合，分离设备中的流体分散和传质，石油和天然气的提取、处理和运输中的两/三相流)。同时，空间和时间尺度的精细分辨率以及大多数界面细节的精细分辨率将使更多的基础研究得以进行。这些将为多相流的许多方面带来新的曙光，这些方面仍然没有得到彻底的了解，这对多相设备的设计和运行产生了负面影响。该项目将受益于与英国和海外受人尊敬的学者(麻省理工学院和北卡罗来纳州立大学)以及在为核工业开发计算产品以及核反应堆热工水力分析和评估(西门子工业软件有限公司和Frazer-Nash咨询公司)方面的密切合作。

项目成果

Large eddy simulation for the modelling of the dynamic behaviour of the DYNASTY natural circulation loop

用于 DYNASTY 自然循环回路动态行为建模的大涡模拟

• 发表时间: 2022
• 作者: Battistini A.

A novel generalized multiphase modelling approach for the simulation of multiphase flows: model development and validation.

用于模拟多相流的新颖的广义多相建模方法：模型开发和验证。

• 发表时间: 2021
• 作者: Colombo M.

Benchmarking of computational fluid dynamic models for bubbly flows

气泡流计算流体动力学模型的基准测试

• DOI: 10.1016/j.nucengdes.2021.111075
• 发表时间: 2021
• 期刊: Nuclear Engineering and Design
• 影响因子: 1.7
• 作者: Colombo M

Prediction of Horizontal Gas-Liquid Segregated Flow Regimes with an All Flow Regime Multifluid Model

用全流态多流体模型预测水平气液分离流态

• DOI: 10.3390/pr10050920
• 发表时间: 2022
• 期刊: Processes
• 影响因子: 3.5
• 作者: Colombo M

Multi-Fluid Computational Fluid Dynamic Predictions of Turbulent Bubbly Flows Using an Elliptic-Blending Reynolds Stress Turbulence Closure

使用椭圆混合雷诺应力湍流闭合对​​湍流气泡流进行多流体计算流体动力学预测

• DOI: 10.3389/fenrg.2020.00044
• 发表时间: 2020
• 期刊: Frontiers in Energy Research
• 影响因子: 3.4
• 作者: Colombo M