摘要
对牛顿流体内溶解与热对流对单颗粒在垂直管道中的沉降运动进行了直接数值模拟.流体运动由守恒方程计算,密度和黏性的变化考虑流场温度变化的影响,通过积分黏性应力和压力获得颗粒的受力跟踪颗粒运动,溶解引起的相变及其形状的变化由溶解潜热、溶解质量与分散相边界处的温度梯度的关系建立的方程决定.通过颗粒和流体间相互的作用力和力矩及边界条件的施加实现相间耦合.分别模拟了颗粒在等温流体、热流体、冷流体及颗粒溶解四种情况下的沉降过程.结果表明,在一定雷诺数内,热对流产生的颗粒尾迹处涡的脱落以及溶解引起的颗粒表面形态的变化引起了颗粒的横向摆动,并使颗粒沉降速度发生了变化.
The influence on the motion of single solid particles in a Newtonian fluid by melting and convection was directly simulated. The fluid motion was computed from the conservation laws. Density and viscosity change with the fluid temperature, the particles move according to the equations of motion of a rigid body under the action of gravity and hydrodynamic forces arising from the motion of the fluid. In the process of melting, a distinctive morphology develops due to the different heat flux around the particle＇s surface, and the thermal gradient determines the melting rate. The phases were coupled by the fluid-particle mutual force, force moment and the boundary conditions. In our study four different situations were considered, namely the sedimentation in isothermal fluid without thermal convection and melting, sedimentation in cool fluid and hot fluid without melting, and sedimentation with thermal convection and melting. The results showed that the vortex shedding arising from the natural convection changes the sedimentation velocity and induces horizontal oscillating.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第9期6369-6375,共7页
Acta Physica Sinica
基金
山西省青年创新基金(批准号:2008021004)
中北大学校基金(批准号:20081002)资助的课题~~
关键词
溶解
热对流
颗粒两相流
直接数值模拟
melting
thermal convection
two-phase flows
direct numerical simulation
