过渡流下分离与再附不稳定性及其传热强化机理的研究

项目名称： 过渡流下分离与再附不稳定性及其传热强化机理的研究

项目编号： No.51476080

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 能源与动力工程

项目作者： 喜冠南

作者单位： 南通大学

项目金额： 83万元

中文摘要： 过渡流有着较强的不稳定性，这种不稳定性具有周期性，能对壁面产生周期性强化作用。尤其在分离和再附中，不稳定性具有三维结构特征，壁面的传热强化机理变得更为复杂。此外，随着换热设备向小型化的发展趋势，部分换热设备内部流动处于过渡流状态的概率变大。因此，研究过渡流下分离与再附不稳定性、传热强化机理具有很高的学术意义及实用价值。本项目首先对过渡流进行理论分析和机理研究，建立相应的数学模型；其次建立相关三维后台阶流动传热数值模型，通过PIV实验及相关传热实验验证上述过渡流传热数值模型；最后系统分析过渡流下分离与再附的流动特性，着重研究过渡流区湍流结构不稳定性的三维特性，继而研究相关壁面的传热强化机理，找到降低流场阻力和提高传热效率的关键因素及有效手段，为高效壁面传热强化换热设备的设计开发提供理论依据。

中文关键词： 强化传热；数值模拟；对流传热；传热特性；不稳定性

英文摘要： The transition flow has stronger instability and its instability has periodicity which can produce the periodical heat transfer enhancement to the wall surface. Especially in the separation and reattachment, instability has a three-dimensional structure, therefore, to make heat transfer enhancement mechanisms to be more complex. In addition, with a compactness trend of heat transfer equipments, internal flow in some of heat transfer equipments has large probability to be in transition flow region. Therefore, the research on instability of flow separation and reattachment and heat transfer enhancement mechanisms in the transition flow has higher academic significance and practical value. In this project, firstly, the theoretical analysis and mechanism researches in the transition flow are studied to establish a corresponding mathematical model. Secondly, a heat transfer numerical model of the three-dimensional backward-facing step, which is validated by PIV experiments and heat transfer experiments, is established. Finally, flow characteristics of separation and reattachment in the transition flow are analyzed systematically and the three-dimension characteristics of instability are researched particularly. And then the heat transfer enhanced mechanisms on the wall are concluded to find the key factors, which reduce flow resistance and improve heat transfer efficiency. It will provide theoretical basis for the design of the high efficiency heat transfer enhancement equipment.

英文关键词： Enhanced heat transfer;Numerical simulation;Convection heat transfer;Heat transfer characteristics;Instability