Boiling and two-phase flows

沸腾和两相流

• 批准号: 41929-2008
• 负责人: Teyssedou, Alberto
• 金额: $ 2.02万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=450879
• 关键词: Boiling; two; phase; flows

Improving the performance of thermal equipment used in the power industry can strongly contribute in re- ducing environmental impacts of burning fuels. In addition, nuclear power plants produce electricity without emissions. Thus, the nuclear technology is now at the foreground of the power industry. A better design of thermal systems can help in reducing conventional plant emissions as well as to guarantee the safe operation of nuclear stations. Therefore, this proposal presents a program intended to study several subjects that could help in improving the efficiency of conventional and nuclear power plants. These subjects are: i) Pressure Losses in Boiling Fluids: their prediction is essential for dimensioning thermal equipment and consequently reducing energy waste. They are calculated with empirical correlations developed from data. In boiling experiments, water is commonly replaced by other fluids. The data is converted into water equivalent values by scaling laws that have been verified only under Critical Heat Flux (CHF) flow conditions. A Freon loop will be used for performing experiments under high-pressure water equivalent flow conditions different from CHF. ii) Flow Distribution in a Full Size Rod Bundle Assembly: pressure losses and heat transfer in fuel channels depend on two-phase flow patterns. A transparent rod-bundle simulation assembly will be manufactured for performing two-phase distribution experiments with air-water mixtures. The flow will be characterized by measuring among other parameters, the local void fractions. iii) Subchannel Analysis: fuel channel thermalhydraulic analyses are carried out with subchannel codes. For calculating lateral mixing effects, these codes require empirical constants to be selected by the user. These parameters, however, depend on local conditions a priori not known. A genetic algorithm coupled to an objective function will be used in a horizontal subchannel model for optimizing lateral mixing without user intervention. iv) 3-D Modeling of the Candu Calandria Vessel: it is intended to introduce more modern simulation techniques than those commonly employed in the nuclear industry. Simulated local flow and temperatures will be used in nuclear safety analyses.

提高电力工业中使用的热力设备的性能可以极大地减少燃烧燃料对环境的影响。此外，核电站发电时不会产生排放。因此，核技术现在处于电力工业的前沿。更好的热系统设计有助于减少常规工厂的排放并保证核电站的安全运行。因此，该提案提出了一项旨在研究有助于提高常规发电厂和核电厂效率的几个课题的计划。这些主题是： i) 沸腾流体中的压力损失：它们的预测对于确定热设备尺寸并从而减少能源浪费至关重要。它们是根据数据得出的经验相关性来计算的。在沸腾实验中，水通常被其他液体代替。数据通过仅在临界热通量 (CHF) 流动条件下验证的比例定律转换为水当量值。氟利昂回路将用于在不同于CHF的高压水当量流量条件下进行实验。 ii) 全尺寸杆束组件中的流量分布：燃料通道中的压力损失和传热取决于两相流模式。将制造一个透明的杆束模拟组件，用于执行空气-水混合物的两相分布实验。将通过测量局部空隙率等参数来表征流动。 iii) 子通道分析：燃料通道热工水力分析采用子通道代码进行。为了计算横向混合效应，这些代码需要用户选择经验常数。然而，这些参数取决于先验未知的当地条件。与目标函数耦合的遗传算法将用于水平子通道模型，以在无需用户干预的情况下优化横向混合。 iv) Candu Calandria 容器的 3-D 建模：旨在引入比核工业中常用的技术更现代的模拟技术。模拟的局部流量和温度将用于核安全分析。