Performing Airflow Analysis using 3DEXPERIENCE Fluid Dynamics Engineer Role (FMK)

Introduction:

Understanding propeller aerodynamics is crucial for optimal performance. Leveraging 3DEXPERIENCE SIMULIA advanced Rotating Zone feature offers a realistic airflow representation, surpassing simpler models. This analysis provides quantitative insights into velocity, pressure, and turbulence. Engineers can then accurately evaluate thrust, efficiency, and noise. Ultimately, this detailed understanding drives the creation of optimized propeller designs for diverse applications.

Workflow

Propeller speed
For this propeller analysis, a rotational speed of 20 RPM was used.

Model preparation: (Creation of rotating zone)

To model the rotating zone around a propeller using the frozen rotor approach, draw a cylinder around the propeller with a diameter 1.3 times the propellers and a length 1.5 times the hubs. This defines the rotating zone, where the flow rotates with the propeller. The rest remains stationary. This method adds rotational effects to the Navier-Stokes equations without needing a moving mesh.

Define the Environment:
Fluid Domain: A fluid domain is a finite volume made up of one or more fluid regions, enclosed by parts, external geometries, and openings. For external fluid flow simulations, it’s necessary to define the exterior geometry to bound the entire space that will be meshed.

Once the boundary has been set, the next step is to define a fluid cavity for stationary and rotating region

Stationary Region: This is the area where there are no moving parts, representing an inertial frame of reference. The fluid in this region remains fixed, with no rotation or movement caused by mechanical components.

Surface Selections
Surface selections are made for defining the flow conditions. Here three surfaces were selected for inlet of fluid, outlet face for pressure outlet of fluid and a surrounding boundary for fluid.

Discretization:
For numerical analysis, we’ll create a computational mesh to discretize the fluid domain. While simulations of high-frequency rotating parts require a refined mesh near the boundary layer to resolve viscous effects, this propeller’s low rotational speed allows us to use a coarser mesh.

Based on the cross-section shown below, it appears that the mesh along the boundary layer is sufficiently refined to run this simulation.

Physics, Boundary Conditions and Execution:
Here Air physics (compressibility, heat transfer, gravity) is defined. A ‘steady state’ step establishes stable airflow. Equation controls are refined (including pressure under-relaxation for rotating parts) to optimize solver accuracy in both rotating and stationary regions.

For simulations involving external fluid flows, the SST k-ω turbulence model is a suitable choice
Set Rotating Zone: Specify the propeller’s rotation speed and axis.
Apply Boundaries: Define inlet velocity, outlet pressure, and wall conditions for the fluid domain.
Set Output Requests: Choose simulation results to extract (e.g., velocity, pressure, forces).

Run Simulation: Execute the solver to compute fluid flow.

Velocity plot: To visualize simulation results, select “Velocity.1” in the Plots window to display flow velocity on the propeller. Also streamlines can be created in results section to identify the flow pattern.

In conclusion, 3DEXPERIENCE SIMULIA Rotating Zone feature provides a more accurate analysis of propeller airflow than simpler methods. This detailed understanding of aerodynamic characteristics, through quantitative measures, enables engineers to precisely evaluate performance metrics and optimize propeller designs for specific applications.

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