MESOSCALE MODELING OF SOLID ROCKET MOTORS

Solid composite propellants (SCP) are ubiquitous in rocket propulsion due to their simplicity, reliability, and stability during long-time storage.

They have been used in applications ranging from the Space Shuttle to hobby rockets, but little has been done to predictively model or optimize their composition for peak performance in the condensed phase.

In this work we develop a model for predicting burn behavior of Ammonium Perchlorate SCPs with binders including hydroxyl-terminated polybutadiene (HTPB) and polybutadiene acrylonitrile (PBAN).

The model is designed to handle the solid and gas phases together, while fully resolving the nuances involved in both.

We begin by developing a phase field (PF) type model that is capable of capturing heterogeneous SCPs and resolving the full complexity of the burn front.

We demonstrate that the model provides accurate results for a variety of composite geometries including sandwich and packed spheres.

We then extend the model to examine the thermoelastic and mechanical response of SCPs during deflagration, as well as predicting ignition behavior. In the last part of the talk, we introduce a novel approach to solid-fluid interaction (SFI) for mass-flux boundary conditions, and provide an overview of the theoretical underpinnings of a diffuse-boundary formulation for resolving a solid-fluid mass flux interface.

Speaker:

Dr. Brandon Runnels is an Associate Professor of Aerospace Engineering at Iowa State University. He obtained his BS in Mechanical Engineering from New Mexico Tech in 2011 and his MS from Caltech in 2012. He completed his PhD work at Caltech, graduating in June 2016. He moved to the University of Colorado Colorado Springs (UCCS) in August 2015, receiving tenure in August 2022, and then moving to Iowa State University in August 2023. Dr. Runnels leads the solid mechanics research group , whose focus is the development of high-performance computational methods for simulating mechanics and materials in extreme environments. His work has been sponsored by the US National Science Foundation, US Office of Naval Research, US Air Force Research Laboratory, Lawrence Berkeley National Laboratory, and Los Alamos National Laboratory. Dr. Runnels has been awarded the US NSF CAREER award and was named the UCCS Engineering and Applied Science Researcher of the Year in 2023.

03.12.2024