气固流化床非球形颗粒传热机制的多尺度建模研究

生物质和固废流化床等能源动力系统中气固作用机理的研究对系统结构放大、设计和优化等方面具有重要的意义。本项目以数值模拟为主要研究手段，过程建模和实验验证相结合的方式对非球形颗粒气固流化床流动和传热等复杂多尺度行为进行研究。首先采用颗粒尺度高精度数值方法模拟典型非球形颗粒-流体系统传热、传质行为，量化流固耦合力和热通量；而后采用这些信息对宏观尺度高效耦合模型中曳力和平均Nusselt数计算公式进行修正，建立通用多尺度模型。最后采用所建立模型模拟流化床反应器内流动和热量的传输过程，探索深层次非球形颗粒传热机制，并开展热态流化床实验予以验证。本项目从非球形颗粒多尺度结构形成机理出发建立通用多尺度模型，充分利用颗粒尺度数值模型给出的传统实验无法获得的微观信息，从基本原理层次为流化床操作技术和能量效率提供优化策略，研究成果将对开发新型流化床和推动大型工业装置的节能减排具有重要的现实意义。

Full knowledge on the complex fluid-particle interaction mechanism in energy and power systems such as biomass and solid waste fluidized beds is of great importance to the scaling design and configuration optimization. In this project, numerical simulation will be employed to investigate the complex flow characteristics of heat and mass transfer in non-spherical fluidized beds together with process modelling and experimental validation. Firstly, particle scale simulations with high precision will be conducted to quantize the coupling force and heat flux in typical non-spherical particle-fluid systems. Then, these information will be used to correct the drag force and averaged Nusselt number in those efficient macro-scale models, depending on which a general multi-scale model can be established. At last, the established model, which is validated by experimental, will be adopted to investigate the heat and mass transfer behavior in a non-spherical fluidized bed and understand the essential heat transfer mechanism of non-spherical particles. The multi-scale model proposed in this project is based on the particle scale information which is extremely difficult to measure by physical experiments, the obtained results can be helpful for providing optimization policy on operating parameters and energy efficiency, which also has important significance on the development of novel fluidized art and energy-saving and emission-reduction of large industrial devices.