自激振荡多尺度瞬时涡量脉动强化传热机理及热流道设计方法研究

The achievement of energy-saving and efficient technology for passive pulsation flow heat transfer enhancement is very significant for the performs of thermal dissipation of the heat transfer equipment. The studies showed that the fluid mixing performance of the chamber wall and pulsed sustainability can effectively be increased by the special structure and specific boundary conditions of the self-excited oscillating chamber. Based on this study, the project focuses on the instantaneous vorticity generated by periodic pulsations and use multidisciplinary integration, involving mechanical engineering, power engineering and engineering thermophysics, and fluid dynamics. Also, a new idea about complex multi-scale instantaneous vorticity pulsation based on the self-excited oscillating effect will be proposed creatively. Firstly, the multi-scale instantaneous vorticity structures characterization method under three-dimensional time-varying feature flow field and the effect of self-excited oscillating pulsation-induced vorticity on heat transfer based on the field synergy principle are studied, then a scientific explanation of the mechanism of passive pulsating enhanced heat transfer can be precisely established. On the condition that, the design of the hot runner wall based on multi-scale instantaneous vorticity interference models and the intelligent synergic optimization of hot runner chamber with multi-objective dimensionless parameters are researched, after that the theory and method system of pulsating heat transfer runner will be established. Finally, the self-excited oscillating vorticity pulsating enhancing heat transfer effect is further evaluated by the experimental of enhancing heat transfer performance. The findings of the research will lay the theoretical foundation for enriching the pulse heat and mass transfer mechanism, and provide a scientific basis of the application of the proposed key technologies in the design of new heat exchanged equipment, which is of great significance of establishing an energy-saving society in our country.

实现节能高效的无源脉动流强化传热技术对换热装备散热性能有重要作用。研究发现：自激振荡腔室的特殊结构和特定边界条件能有效提高腔室壁面的流体掺混性能并增强其脉动持续性。基于此，项目聚焦周期性脉动产生的瞬态涡量，利用机械工程、动力工程及工程热物理和流体力学等多学科交叉融合，创新性地提出基于自激振荡效应的复杂多尺度瞬时涡量脉动传热新观点。项目首先研究三维时变特征流场下多尺度瞬时涡结构的表征方法和基于场协同原理的自激振荡涡量脉动热传递效应，建立精准的无源脉动强化传热机理的科学解释；在此基础上，研究基于多尺度瞬时涡间干涉模型的热流道壁面设计和腔室无量纲结构参数的多目标智能协同优化，建立脉动换热流道的设计理论与方法体系；最后，通过强化传热性能实验进一步评价自激振荡涡量脉动强化传热效果。项目研究将为丰富脉动传热传质机理奠定理论基础，并为新型换热装备设计关键技术提供科学依据，对我国建立节能型社会有重要意义。

项目结合无源脉动强化传热机理降低传热能耗相关研究的热点和难点，对基于自激振荡效应的复杂多尺度涡量脉动传热、自激振荡瞬态脉动涡结构的提取和表征方法和基于多尺度涡间干涉模型的自激振荡热流道设计理论及方法三个方面进行探讨，主要研究工作如下：.（1）借助Liutex-Omega涡识别方法对多尺度涡环结构的合并与破碎过程进行分析，依托涡结构所具有的结构尺度和时间尺度，获取影响涡环结构生成的主要因素；根据涡结构的特性，分析了腔室内涡结构的强度脉动趋势，有效避免了传统可视化方法在降维过程中的信息遗漏或显示过度复杂等问题。.（2） 依据大涡结构在自激振荡腔室内的蓄能及释能状态，揭示了自激振荡脉动流热场协同模型及涡量脉动热传递效应。利用场协同理论，分析了温度矢量和速度矢量对传热性能的影响，揭示了考虑流体脉动特性的复杂传热传质过程中的流热性能，实现了涡量脉动的高效热传递。.（3） 研究多尺度涡结构分布的瞬时非定常涡间干涉模型的热流道壁面设计方法，改变影响自激振荡脉动效果的主要结构参数，通过数值方法分析其涡结构干涉现象对换热性能的影响，通过非定常涡干涉模型，分析影响次生涡干涉的主要因素，进一步优化了流场流动特性并提高热交换效率。.（4） 热流道腔室无量纲结构参数的多目标智能协同优化对脉动换热性能有重要影响，通过中心复合设计实验方法，构建Kriging响应面近似模型，利用交叉参考线和DPD评估的MOEA-CRL协同优化方法，获取最优的腔室无量纲结构参数，为开发高效通用型的热结构优化设计算法提供了科学依据。.（5） 搭建自激振荡热流道强化传热性能实验平台，进行了不同工况下的平均努塞尔数、阻力系数、脉动频率和脉动振幅等关键参数测试实验，计算并完成了换热效果评价，实现了无源脉动强化传热机理与新型装备设计理论及方法的协调优化。.项目研究将为换热装备关键设计方法及传热数值模拟与计算奠定理论基础，对提高我国节能型装备关键技术的核心竞争力具有重要意义，具有广阔的应用前景。