CFD Methodology Development to Predict Lubrication Effectiveness in Electromechanical Actuators Eaton India Innovation Center

Format:

Book

Conference/Event

Author/Creator:

Bhardwaj, Divyanshu, author.

Contributor:

George, Jubin

Kumar, Anant

Conference Name:

AeroCON 2024 (2024-06-06 : Bangalore, India)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2024

Summary:

Electromechanical actuators (EMAs) play a crucial role in aircraft electrification, offering advantages in terms of aircraft-level weight, rigging and reliability compared to hydraulic actuators. For various functions within the actuator such as prevention of backdriving, torque limiting, damping, braking, et cetera, skewed roller devices are typically employed to provide braking torque. These technology components are continuing to be improved with analysis driven design innovations e.g., U.S. Pat. No. 8,393,568. The device has the rollers skewed around their own transverse axis that allow for a combination of rolling and sliding against the stator surfaces. This friction provides the necessary braking torque. By controlling the friction radius and analyzing the Hertzian contact stresses, the device can be sized for the desired duty cycle. While operating, the rollers require sufficient lubrication to ensure local temperatures do not exceed limits of the components or the lubricant itself. This was analyzed by multiphase computational fluid dynamics (CFD) modeling to predict fluid characteristics around the skewed rollers and conjugate heat transfer modeling to identify component overheating. Elasto-Hydrodynamic lubrication (EHL) theory was used to estimate the lubrication thickness around the rollers. The analysis revealed the formation of vapor due to the high rotational speed of the rollers with respect to the stator discs, resulting in direct metal-to-metal contact. Consequent testing of the device in a Tribological Testing Machine confirmed the findings with wear patterns on the stator consistent with loss of lubrication. In addition, the temperature data aligned within 2°C of predicted CFD results at key locations on the device. Given the high fidelity of the analysis methodology, future steps include assessing new design iterations against intended performance parameters

Notes:

Vendor supplied data

Publisher Number:

2024-26-0466

Access Restriction:

Restricted for use by site license