WEG Electric Motor Corporation is the largest Latin American electric motor manufacturer and is present on five continents in more than 60 countries. The company develops a large part of its own technology and has been using CFD to improve products performance.

One particular interest is the cooling systems of electric motors. The cooling system is responsible for keeping the temperature of the internal components within a specific range to maintain or increase the life of the motor.

Because of the complex geometry, a computational mesh was created using tetrahedral elements, and prism layers were added at the walls to capture the boundary layer effects. The main objective of the analysis was to evaluate the velocity profile at the channel between the fins. The CFD model included the fan rotor. A far field type of boundary condition was imposed in such a way that the air flow rate was driven by the fan rotor. The resulting grid size was about 2.2 million nodes and demanded just 220 iterations to converge (1e-5 RMS residual) using a high-resolution advection scheme. The high-quality ANSYS ICEM CFD tetra/prism mesh, together with the robustness and accuracy of the ANSYS CFX coupled solver, made this task easy and fast. After results were obtained, air velocity profiles at channels between the fins were compared against experimental measurements and showed very good agreement.

CFX results permitted WEG engineers not only to visualize the air velocity profiles in the channels, which are related to the heat transfer coefficient and have been previously measured experimentally, but have also provided a complete understanding of the flow and heat behavior. This is helping to improve the heat transfer coefficient on this equipment, to create better products and to reduce the design time.

WEG Motors electric motors. Courtesy of WEG Motors.

ANSYS CFX enabled engineers to understand air velocity profiles and improve the heat transfer coefficient.

The CFD results were compared with smoke experiments.