1. XFlow™ 培训
第 10章
Discrete Phase Model
离散相模型
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2. Continuous phase flow field
10 – Discrete Phase Model
XFlow allows to simulate a discrete second phase consisting of spherical particles (droplets, dust, bubbles, etc) dispersed in the continuous phase
Xflow可模拟连续相介质流动中分散的离散相（球粒、液滴、气泡、尘埃等等）
One-way coupling: 单向耦合
- Fluid flow influences particles via drag and turbulence 通过阻力和湍流作用于粒子
- Particles have no influence on the fluid flow 粒子对流场没有影响
No particle-particle collisions 无粒子间的碰撞作用
Transient: each particle advances in time along with the flow 每个粒子随着流动场瞬态变化
Steady: velocity field at a reference frame 稳态：参考帧的速度场
Dispersion of particles due to turbulent fluctuations (only when averaged and standard deviation results have been saved) 湍流脉动促使粒子的分散
Particle streams are injected from a shape 从形状上注入粒子流
Continuous phase flow field
连续相流场
Particle trajectory
粒子轨迹
In addition to solving the transport equations for the continuous phase, XFlow allows to simulate a discrete second phase in a Lagrangian frame of reference. This second phase consists of spherical particles (which may represent droplets, dust, bubbles, etc) dispersed in the continuous phase.
XFlow features the following discrete phase modeling capabilities:
calculation of the discrete phase trajectory using a Lagrangian formulation that includes the discrete phase inertia, hydrodynamic drag, and the force of gravity, for both steady and transient flows
prediction of the effects of turbulence on the dispersion of particles due to turbulent eddies present in the continuous phase

3. 10 – Discrete Phase Model Behaviour: DPM 粘性模拟 Source源 Inlet 入口
Number of tracers 迹线数
Particles flux rate 粒子流率
Particle properties 粒子特性
Density (ρp) 密度
Diameter (for drag coefficient FD)直径
Standard deviation (in particle diameter)标准偏差
Restitution coefficient (for collision with surfaces)恢复系数
Velocity laws (initial velocity)初始速度
Acceleration laws (a1 and a2) 加速度
Timing 时间
Transient: Off/On 瞬态开关
Colored by field 颜色场
Data数据
Restitution coefficient = 0
Restitution coefficient = 0.5
DPM
Geometry (shape that will be the source of stream tracers)
Number of tracers (number of seed points for the streamlines)
Particles flux rate (number of particles per second)
Particle density
Particle diameter
Particle standard deviation
Particle restitution coefficient (1= perfectly elastic, 0= perfectly inelastic)
Velocity laws
Acceleration laws
Transient: Off/On
Restitution coefficient = 1

4. 10 – Discrete Phase Model Behaviour: DPM Source Inlet
Number of tracers
Particles flux rate
Particle properties
Density
Diameter
Standard deviation
Restitution coefficient
Velocity laws
Acceleration laws
Timing
Transient: Off/On
Colored by field
Data
Number of tracers = 0 produces stream tracers at random positions on the specified inlet
0个迹线表示在入口随意位置指定流迹
Flux rate = 0 generates just one sequence of particles
流率=0，表示只产生一个序列的粒子
Transient: Off
Reference frame
Time
Transient: On
Initial frame
Last frame
DPM
Geometry (shape that will be the source of stream tracers)
Number of tracers (number of seed points for the streamlines)
Particles flux rate (number of particles per second)
Particle density
Particle diameter
Particle standard deviation
Particle restitution coefficient (1= perfectly elastic, 0= perfectly inelastic)
Velocity laws
Acceleration laws
Transient: Off/On

5. 10 – Discrete Phase Model
Different variables for particles and fluid 粒子和流体不同变量
Number of active particles激活的粒子数目
Right click in Function Viewer > Data stream tracers > Tracer # > Active particles
Measure particles through outlet 出口测量粒子
Right click in Function Viewer > Data stream tracers > Tracer # > Outlet particles flux
particle_x, _y, _z
fluid_px, _py, _pz
particle_vx, _vy, _vz
fluid_vx, _vy, _vz
particle_t
fluid_sp
fluid_vrt
Different variables for particle and fluid