考虑风致振动的膜结构屋盖附近耦合流动与传热机理研究

As a typical lightweight and flexible system, membrane structure is susceptible to wind load， and its thickness and thermal insulation are insufficient. However, the mechanism of coupled flow and heat transfer near the membrane roof with wind-induced vibration isn’t very clear. The engineering application of membrane structure and the assessment and control of thermal environment are restricted seriously.In the project, the quantitative relationship between coupled flow boundary layer and thermal boundary layer under the wind-structure interaction with main control parameters is studied using scaling analysis and numerical simulation. The evolution of flow regimes and flow structures with Reynolds number, Rayleigh number and rise span ratio is found using multi-physics coupling simulation. The characteristics of vortex shedding and flow instability are also investigated. The main cases based on the measured data are tested using wind tunnel experiments. On the other hand, the study include the influence of wind-load, solar radiation intensity, roof open or shut mode and internal heat source location on temperature field. We try to emphasize the important effect of the special boundary conditions and flow structures on the heat flux and the physical mechanism of formation and evolution processes. The investigation is a beneficial exploration to demonstrate the dynamic mechanism and the heat transfer law of coupled flows near the membrane roof. The results are expected to provide a theoretical basis for energy conservation design of membrane structure.

膜结构是一种典型的轻质、柔性体系，对脉动风荷载的作用十分敏感，并且膜材厚度有限，保温隔热等热工性能不足。然而，考虑风致振动的膜结构屋盖附近耦合流动与传热机理尚不十分清楚，这严重制约了膜结构屋盖的工程应用及其内部热环境的评价与控制。本项目拟采用量纲分析和数值模拟方法，研究风致振动的膜结构屋盖附近耦合流动边界层和热边界层与控制参数间的定量关系。采用多物理场耦合数值模拟，研究耦合流场流态和主要流动结构随雷诺数、瑞利数和矢跨比的变化，分析涡脱落特性和流动稳定性，并根据实测数据对主要工况进行风洞试验。研究风荷载、太阳辐射强度、屋盖开闭状态、内部热源位置等对温度场的影响，确定对流换热的重要影响条件和特殊流动结构，及其形成和发展的物理机制。本项目拟揭示膜结构屋盖风振响应中耦合流动转捩和传热机理，为膜结构建筑节能设计提供可靠的理论依据。

膜结构屋盖是一种新型轻质、柔性体系，对脉动风荷载的作用十分敏感，在大跨煤棚等结构中应用广泛，因为保温隔热等热工性能不足，导致结构内热环境恶劣。这严重制约了膜结构屋盖的工程应用及其内部热环境的评价与控制。.本项目采用量纲分析和数值模拟方法，研究风致振动的膜结构屋盖附近耦合流动边界层和热边界层与控制参数间的定量关系。采用多物理场耦合数值模拟，研究耦合流场流态和主要流动结构随雷诺数、瑞利数和矢跨比的变化，分析涡脱落特性和流动稳定性，并根据实测数据对主要工况进行试验研究。采用风洞试验研究了煤棚结构表面风荷载，对比分析各风向角下，天窗位置测点的体型系数，90°风向角下体型系数绝对值较大，风压较大，应适当对其加固。研究了封闭式单热源煤棚内部流动传热特性，煤棚内瞬态流动会经历三种不同发展阶段：初始阶段、演化阶段、充分发展阶段，在演化过程中羽流脱落分离会推动煤棚内非对称结构形成，非对称现象出现的时间会随瑞利数增大而提早。煤棚内部流动在充分发展阶段呈现无规则的非定常湍流流动特性，且达到充分发展状态的时间随瑞利数增大而推迟。研究了有开口的双煤堆煤棚内流动传热特性，流态随雷诺数增长由湍流向周期转变，在一定范围内雷诺数增大对流换热增强。分析了外界太阳辐射强度、屋盖开闭状态、内部热源位置等对温度场的影响，对流换热的重要影响条件和特殊流动结构，及其形成和发展的物理机制。.本项目对膜结构屋盖风振响应中耦合流动转捩和传热机理提供了理论解释，为膜结构建筑节能和热环境优化设计提供了参考。