Tips About DPM To simulate the evaporation process of droplets, we need to define the…
DPM Injection and Particle Types
Discrete Phase Model
In numerical and theoretical studies of multiphase flows, you can writhe the governing equations of the flow separately for each phase. Two approaches can be used to study the motion of each phase. The first approach is Eulerian-Eulerian methods, in which the governing equations of each of the continuous and discrete phases must be written based on the Eulerian view. However, in the Eulerian-Lagrangian approach, continuous phase equations are applied from Eulerian’s point of view, while discrete phase equations are written and used using Lagrangian laws.
DPM Injection Type
Ansys fluent software has provided different types of injections that we can use according to the type of injection and are as follows:
Single, group, Cone, surface, file, volume, plain orifice atomizer, pressure swirl atomizer, air blast atomizer, flat fan atomizer, effervescent atomizer
What are the “Injection” conditions in Fluent?
For Transient problems and to detect unsteady particle tracking, the injection start time and stop time should be specified in the point properties section. If we set the value to zero for the start and end of the injection, they are injected only at the moment of starting.
In a nozzle, the discharge coefficient is equal to the ratio of actual discharge to ideal discharge, and you can express its mathematical relation as follows:
- Where C_d is the discharge coefficient
- m ̇mass flow rate
- fluid density
- Volumetric volume
- A cross-section
- u fluid velocity
- And ∆p is the pressure drop.
Adjust the particle velocity flows along the spray cone angle specified in the “Velocity” section.
DPM Injection Initial Conditions
For the injection to take place, you must define the injection properties. The injection properties are:
We need to specify the injection site to inject from that area.
By specifying this parameter, you can determine the direction and speed of particle injection.
Specifies the particle temperature.
• Start time & Stop time
The injection starts and stops time must be specified in the point properties section to detect unsteady particles.
• Drop size distribution
We can determine how the droplet size distribution works.
• Flow rate
We also need to determine the mass flow rate of the particles.
The initial injection conditions are essential for spray simulation. The internal flow of the injector has strong effects on the external spray.