Spray Dryer ANSYS Fluent CFD Simulation Tutorial

Project Description

In this product, a spray dryer is simulated by ANSYS Fluent software. The feed solution (slurry, paste, etc.) is first conveyed to the atomizer via a tank using a pump. The atomizer disperses the liquid solution as a spray or liquid droplets into the main dryer compartment.

On the other hand, hot air, which rises from a burner or steam heater, blows into the chamber by a fan. At this point, the liquid phase of the spray contacts hot air so that the moisture within the droplets evaporates within a short time, leaving the powdered dry particles with the hot air out of the chamber.

We have used two types of continuous and discrete phases in the present problem. The hot airflow, responsible for evaporating the moisture in the solution, enters the spray dryer chamber as a continuous phase and flows into the chamber (Eulerian). The geometry of this project has been designed using Design Modeler software. The mesh was created on this geometry using ANSYS Meshing software.

The mesh type is unstructured, and the element number is 84047.

Spray Dryer Methodology

We have used the Species Transport Model in this simulation. It is assumed that the inlet’s hot and dry airflow has a very small amount of (about 0.009%) water vapor. Also, some moisture air comes into the inlet air with the feed solution. So the inlet air with the solution contains water vapor.

Therefore, in addition to receiving moisture from the feed solution, the inlet hot air flow also has the task of drying the humid air with the solution. In addition, there is a solution consisting of water and solid particles. Whose purpose is to separate the water droplets or the moisture from the particles.

By choosing the Interaction With Continuous Phase, the behavior of the selective discrete phase flow (water droplets) interacts with the continuous flow (hot air).

Spray Dryer Conclusion

As can be seen in the pictures, the velocity, pressure, temperature, and particles injected into the domain are clear. Based on the spray dryers’ function, particles penetrate the domain at high speed. While a hot air stream enters from around. The behavior of the particles in the air and their penetration and breakup length are also discussed.

Combining these two phases, which enter the domain in Eulerian and Lagrangian, leaves the outlet uniformly at a temperature lower than the air inlet temperature.