纵向涡间干涉的描述参数及其与纵向涡强化传热对应关系研究

The longitudinal vortices are widely used to enhance the heat transfer performance of heat exchangers. But the longitudinal vortices will interact with each other when they meet in the flow channel and the heat transfer performance is always affected by the interaction between the longitudinal vortices. Unfortunately, few studies have focused on the interaction between vortices and their effect on heat.transfer enhancement. The description parameter for interaction of longitudinal vortices is still not reported yet. A deeper understanding of the interaction of longitudinal vortices and their effect on heat transfer performance can identify the desirable features of vortices for heat exchanger geometries and point toward designs that can exploit their full potential, which is also pertinent to many engineering problems. Therefore, there is a strong need of description parameter for evaluating the degree of the interaction between longitudinal vortices and their effect on heat transfer. The main research contents of this project are: (1) The developing characteristics of the longitudinal vortices and the method for determining the space between different longitudinal vortices by using the parameters of vortex generators; (2) Defining a parameter named as interaction factor for the description of the interaction between longitudinal.vortices; (3) The qualitative relationship between the interaction factor and the fin performance of fluid flow and heat transfer. The research objects are the obtainment of interaction factor and the guiding principle for optimization design of fins basing on the interaction factor. The guiding principle can be used to exploit the full potential of heat transfer enhancement performance of longitudinal vortices without carrying out numerical simulation. The research results of this project can promote the deeper research and understanding of interaction between longitudinal vortices and guide the application of interaction factor for the optimization design of fins. Thus, the research of this project has not only theoretical significance but also value of practical application.

纵向涡强化传热技术在换热器中得到了广泛应用。但是，纵向涡间相遇时不可避免的存在相互干涉，而纵向涡间的干涉影响着纵向涡的强化传热效果。目前关于纵向涡干涉的研究甚少，对纵向涡干涉描述参数的研究还没有文献报道。纵向涡干涉描述参数的缺乏使得对涡干涉的认识理论不足，工程应用价值不强，无法更好地利用涡干涉达到最佳换热性能。本项目将开展如下研究：(1)认识纵向涡发展衰减变化规律，通过涡产生器结构参数确定纵向涡间距；(2)定义纵向涡间干涉程度的定性描述参数—纵向涡干涉系数；(3)纵向涡干涉系数与纵向涡强度及翅片换热性能之间的定性关系。项目研究目标是：获得纵向涡干涉系数和基于纵向涡干涉系数的翅片性能优化设计原则，该优化原则可使纵向涡干涉规律不经过数值模拟而方便的应用于翅片优化设计。项目研究结果可促进纵向涡干涉系数在纵向涡干涉研究及翅片优化中的应用，进一步发掘纵向涡强化传热的潜力，具有理论意义和工程应用价值。

在采用纵向涡强化传热的换热通道内，纵向涡间不可避免的存在相互干涉，而纵向涡间的干涉影响着纵向涡的强化传热效果。如何根据涡产生器参数及其布置参数定义纵向涡干涉系数来直观的描述涡产生器产生的纵向涡之间的干涉是本项目研究的关键任务。项目针对翼型涡产生器产生的旋转方向不同、旋转方向相同的两个纵向涡之间的干涉模型，翅型涡产生器产生的成对的相反旋转方向的纵向涡之间的干涉模型，波纹换热通道以及管翅换热通道内纵向涡间的干涉等多个模型，研究了涡产生器尺寸、攻击角、间距、布置方式等参数对纵向涡间干涉规律、干涉后纵向涡强度变化及流动换热的影响，分析了涡产生器结构参数和布置方式等参数与纵向涡干涉间的关系。定义了描述纵向涡间干涉程度的参数—纵向涡干涉系数。纵向涡干涉系数反映了涡产生器间相对位置、布置方式、涡产生器尺寸、攻击角等参数对纵向涡干涉的影响。并针对不同的纵向涡干涉类型及多种涡产生器结构参数考核了纵向涡干涉系数用于描述纵向涡间干涉程度的适用性。通过纵向涡干涉系数探索了不同纵向涡干涉类型之间的纵向涡干涉规律，确定了翅片表面具有较优换热性能时对应的涡产生器布置方式和纵向涡干涉系数的范围。采用人工神经网络与多目标优化算法相结合对翅片进行了优化。项目研究结果可促进纵向涡干涉系数在纵向涡干涉研究及翅片优化中的应用，进一步发掘纵向涡强化传热的潜力，具有理论意义和工程应用价值。