Icing on aircraft, ANSYS Fluent CFD Simulation

Description

In this project, we present a numerical simulation of the Icing process on an Aircraft using ANSYS Fluent software. We have modeled an aircraft containing two warm nacelles. Note that we design the half of the aircraft body and consider the surrounding airflow as the computational domain.

Icing Definition

Icing is the production process of forming an ice layer on flying objects. This icing phenomenon is caused by the impingement and freezing of supercooled droplets or the accumulation of ice crystals onto air vehicles flying in cold airflow.

Methodology

We carried out the icing simulation in three principal steps (with corresponding appropriate solvers) in ANSYS Fluent software:

1. Airflow Simulation

2. Particles Calculation

3. Ice Accretion Simulation

Airflow Solver:

We simulate the traditional airflow (without icing) around the aircraft to provide a basic analysis from an aerodynamic point of view.

Particles Solver:

We set Fluent launcher to the Enterprise level to use the Icing solver in ANSYS Fluent. Then, we import the initial solution data obtained from the airflow simulation.

In the present project, we model both Droplets and Crystals as the particle type required for preparing the icing process. The droplets refer to supercooled water droplets that exist in liquid form at lower ambient temperatures. However, the ice crystals refer to the solid particles suspended in the airflow.

Ice Accretion Solver:

After the particle calculations are complete, it is time for the final calculations to simulate icing.

In the present project, we define the Glaze model as the physical model described the icing condition. This is the most comprehensive model that can operate above and below freezing temperatures.

Conclusion

We represent the final results in two sections (airflow simulation and icing simulation):

1. We obtained contours related to the distribution of the velocity, pressure, and temperature. These velocity and pressure distributions around the aircraft body and its components (like wings and nacelles) confirm the reasonable behavior of the aircraft from an aerodynamic approach.

2. We obtained the distribution contours corresponding to the various icing variables, including ice thickness, ice film thickness, and ice growth. In addition, since we have modeled the droplet and crystal particle types, we obtained the distribution contours for droplet concentration, droplet collection, crystal concentration, and crystal collection. These resulting distributions confirm the ice generation on the aircraft concentrated on the different parts of the aircraft, such as the nose and tail, the leading edge of the wing, and the engine nacelles.