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冷却是热工水力设计的主要成就，因此对核电站的安全和性能具有最大影响。通常，这种热工水力设计和工厂安全评估依赖于计算模型，该模型通过提供物理系统的数学表示来预测冷却剂的流体动力学行为和系统中的传热速率。在核电站中，在正常运行条件下或在需要紧急冷却的事故情况下，这通常需要解决气液多相流问题。不幸的是，尽管现在可以使用任何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，克服这些限制并远远超出当前可用的能力。目前，不同的技术在不同且明确的流动条件下达到了良好的精度，但在没有流态先验知识的情况下，没有一种技术能够成功地模拟气液多相流的整个范围。这极大地限制了可用模型对具有工业意义的流动的适用性，因为这些模型很少表现出相同的良好表征和定义的流动特征。在该项目中，通过新颖的数值技术，先进的建模方法将耦合在同一计算模型中，并根据对当地流动条件的适用性选择性地应用。这将确保多相气液流的准确性和前所未有的适用性，避免限制性假设，但同时避免不切实际的计算要求。在核领域，这样的模型将提供领先的建模和模拟功能，为当前反应堆的改进运行奠定基础机队以及未来工厂的设计和评估。可靠的预测将为反应堆设计和安全限制评估提供信息，减少经验主义和保守主义。此外，昂贵的实验数量将仅限于较少数量的模型驱动测试。更安全、发电价格更便宜、废物足迹更少的反应堆将支撑政府到 2050 年新增 16 吉瓦至 75 吉瓦核电产能的计划。这一新产能对于确保安全、可持续和低排放至关重要。 -英国的碳能源未来，并遵守具有法律约束力的承诺，即到 2050 年将碳排放量比 1990 年减少至少 80%。此外，这项工作将在核领域之外得到更广泛的应用跨所有工程分支利用气液多相流的众多工业设备的设计和操作的优化（例如，鼓泡塔中气泡的增强混合、分离设备中的流体分散和传质、萃取中的两相/三相流） 、石油和天然气的处理和运输）。与此同时，空间和时间尺度以及大多数界面细节的精细分辨率将允许进行更多的基础研究。这些将为多相流的许多方面提供新的认识，这些方面仍然缺乏透彻的理解，从而对多相设备的设计和运行产生负面影响。该项目将受益于与英国和海外知名学者（麻省理工学院和北卡罗来纳州立大学）和工业领袖在核工业计算产品开发以及核反应堆热工水力学分析和评估方面的密切合作。 （西门子工业软件有限公司和弗雷泽-纳什咨询公司）。

项目成果

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.

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: http://dx.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

Preliminary results of the experimental campaign conducted on the dynasty natural circulation loop.

王朝自然循环循环实验的初步结果。

• 发表时间: 2022
• 作者: Benzoni G.

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.

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: http://dx.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