非牛顿流体高浓度液固两相流动相间作用机理研究

Hydrodynamics of dense non-Newtonian fluid-solid two-phase flow are constrained by collisions of wet particles and turbulence of fluid. In present proposed project, the hydrodynamic mechanics of dense non-Newtonian fluid-solid two-phase flow are investigated. The experimental system of the liquid-solid fluidized bed with measurements is constructed with power-law fluid of styrene oxide and Bingham fluid of the nonhydrolytic polyacrylamide and crosslinking agent solution as fluid phase, and catalyst particles and glass beads as solid phases. The velocities and fluctuation velocities of particles and fluid are measured using a CCD camera technique and particle imaging velocimetry (PIV) technique in the liquid-solid fluidized bed. Based on contact theory and liquid bridge theory to consider the effect of interstitial non-Newtonian fluid between particles on contact forces, the collisional model of wet particles is established. The effects of contact forces on momentum and energy transfer and dissipation are discussed. The kinetic theory of wet granular flow is derived using the collision interval theory of kinetic theory of dense gases. The effect of the liquid concentration turbulence on turbulent kinetic energy transfer and dissipation is simulated by large eddy simulation（LES）, in order to reveal the interaction relationship of particles and non-Newtonian fluid. The Euler-Euler two-fluid model for flow of non-Newtonian fluid-solid mixture with high concentration of particles is proposed to study the interaction mechanism of liquid and solid phases . The project will provide a foundation for prediction of macroscopic hydrodynamics of dense non-Newtonian fluid-solid two-phase flow.

高颗粒浓度非牛顿流体液固两相流动特性受“湿”颗粒相互碰撞作用和非牛顿流体湍流作用不同机制的协同。本项目以高颗粒浓度非牛顿流体液固两相流动为研究对象。采用催化剂颗粒等为固相、氧化苯乙烯以及非水解聚丙烯酰胺和交链剂水溶液非牛顿流体为液相，应用高速摄像和粒子图像测速仪测量颗粒和流体速度及脉动速度分布规律。以接触力学理论和液桥理论为基础，建立非牛顿流体“湿”颗粒碰撞动力学，分析颗粒润湿效应对湿颗粒碰撞的效应。以稠密气体分子运动论为基础，应用碰撞间隔理论，建立“湿”颗粒动理学，分析“湿”颗粒碰撞中动量和能量传递和耗散的影响。采用非牛顿流体大涡模拟计算模型，分析液体浓度脉动对液相湍动能传递和耗散的影响，揭示非牛顿流体与颗粒之间相互作用的内在关系。应用高颗粒浓度非牛顿流体的液固两相双流体模型，分析液固两相相间作用机制和协同作用，为正确预测高浓度液固两相流动奠定理论基础。

高颗粒浓度非牛顿流体液固两相流动过程广泛存在于工业过程，非牛顿流体液固两相流动过程存在强烈的颗粒之间碰撞作用，颗粒间相互碰撞改变颗粒动力学，产生动量和能量的交换，影响颗粒湍流特性，也使得描述液固两相流动模型中需要考虑颗粒相互碰撞作用力，改变了液固两相流动计算模型。非牛顿流体的流变性改变了流体湍流流动过程中动量和能量的传递特性，影响流体与颗粒之间的相间作用，进而影响高颗粒浓度非牛顿流体液固两相流体动力特性。由此可见，液体湍流作用下高颗粒浓度非牛顿流体液固两相流动过程受非牛顿流体颗粒相间作用和颗粒之间相互碰撞作用的控制，液固相间作用的协调和控制影响了反应器内液固混合、热量及质量传递速率等。本项目基于稠密气体分子运动论，建立高颗粒浓度非牛顿流体两相流动中的“湿”颗粒动理学，揭示高颗粒浓度非牛顿流体两相流动过程中非牛顿流体液膜润滑作用力下颗粒与颗粒之间的动量和能量传递以及耗散规律。考虑颗粒浓度和速度的脉动对液相浓度脉动的影响，构建考虑颗粒浓度脉动效应的非牛顿流体大涡模拟计算模型，分析液体浓度脉动对液相湍流能传递和耗散的影响。建立非牛顿流体与颗粒脉动速度互关联矩模型，揭示高颗粒浓度非牛顿流体液固相间动量和能量传递规律。结合“湿”颗粒动理学和大涡模拟方法，构建高颗粒浓度非牛顿流体液固两相欧拉-欧拉双流体模型，分析液固相间作用对高浓度液固两相流体动力特性的协同规律，为正确预测高颗粒浓度非牛顿流体液固两相宏观流动奠定理论基础。所建立的“湿”颗粒动理学，研究湍流作用和非牛顿流体液膜润滑作用力对颗粒碰撞属性的传递规律，揭示湿颗粒之间相互作用机理，拓宽了原有颗粒动理学的应用范围；揭示非牛顿流体与湿颗粒之间的相互作用机理，阐明了液固两相动量和能量传递与耗散的协同规律。本项目取得主要成果：发表SCI收录论文15篇，EI收录论文2篇，申请发明专利2项，获得黑龙江省科技奖自然科学二等奖1项，培养硕士研究生6人，博士研究生2人。