Numerical and experimental studies of heat transfer in steady and unsteady laminar or turbulent natural and mixed convective flows

稳定和非稳定层流或湍流自然对流和混合对流传热的数值和实验研究

• 批准号: 5573-2009
• 负责人: Oosthuizen, Patrick
• 金额: $ 1.53万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=504967
• 关键词: Numerical; experimental; studies; heat; transfer

Research in five areas involving convective heat transfer will be undertaken. A number of electronic and electrical components are air-cooled using natural convection and involve geometric shapes that have not been dealt with in basic natural convective heat transfer studies. In the first part of the present work equations that can be used to predict the heat transfer rate in such situations will be developed. Both numerical and experimental studies will be undertaken. In the practical applications considered in the first area of research there is sometimes a low velocity flow over the components. The forced air velocity in such situations is often so low that the heat transfer is by mixed natural and forced convection. Such flows will be considered in the second area of research. Both numerical and experimental work will again be undertaken. The main aims of this work will be to define the conditions under which mixed convection exists. No systematic studies of numerical results obtained using a range of turbulence models for situations involving natural and mixed turbulent convective flows which are similar to air flows in buildings and for which experimental results exist have been undertaken. Such a study will be undertaken in the third study area, the main purpose being to derive recommendations as to which turbulence model to use in a particular flow situation. Most studies of heat transfer across window-blind systems assume that the natural convective flow over the room side of such systems is laminar. Turbulence and unsteady flow can, however, develop in such flows. Therefore in the fourth part of the research basic experimental and numerical studies of the development of turbulent and unsteady flow in window-blind systems will be undertaken. Gas flows in mini-channel systems in which the channel follows a wavy path will be considered in fifth part of the work. Such mini-channel systems are used in a number of practical situations and the flow in these systems can become unsteady at Reynolds numbers that are lower that that at which turbulent flow develops. The purpose of the study is to determine how the channel geometry affects the conditions under which unsteady flow develops.

将在涉及对流传热的五个领域进行研究。许多电子和电气部件使用自然对流进行空气冷却，并且涉及在基本自然对流传热研究中未处理的几何形状。在本工作的第一部分，可以用来预测在这种情况下的传热速率方程将被开发。将进行数值和实验研究。在第一个研究领域考虑的实际应用中，有时会有低速流流过部件。在这种情况下，强制空气速度通常很低，以至于热传递是通过混合的自然对流和强制对流进行的。第二个研究领域将考虑此类流动。数值和实验工作将再次进行。这项工作的主要目的是确定混合对流存在的条件。对于涉及自然和混合湍流对流（类似于建筑物中的空气流动，并且已有实验结果）的情况，使用一系列湍流模型获得的数值结果没有进行系统的研究。这种研究将在第三个研究区域进行，主要目的是就在特定流动情况下使用哪种湍流模型提出建议。大多数关于百叶窗系统传热的研究都假设百叶窗系统房间一侧的自然对流是层流。然而，在这种流动中会产生紊流和非定常流。因此，在研究的第四部分中，将对百叶窗系统中湍流和非定常流的发展进行基础实验和数值研究。在第五部分中，我们将考虑微通道系统中的气体流动，其中通道遵循波状路径。这种微型通道系统用于许多实际情况中，并且这些系统中的流动在低于湍流发展的雷诺数的雷诺数下可能变得不稳定。研究的目的是确定渠道的几何形状如何影响的条件下，不稳定流的发展。