Advanced mesoscale solid-gas modeling of AP/HTPB/Al propellant
Abstract
This proposed project will improve the capability of PF modeling methods, including extending -PF modeling to aluminized propellants including AP/HTPB/Al. The project consists of a five-goal -approach. Goal 1: Simulation of powder agglomeration. Metal additives are known to accumulate -at the burn surface, aggregate into particles, and leave the burning surface as agglomerates. This -will be tracked using the addition of a third species parameter, inclusion of both agglomeration and -burn kinetics, as well as topology analysis to determine detachment events. Goal 2: Monolithic -simulation of reaction flow chemistry and heat trasfer from the fluid phase. Previous work has -demonstrated the utility of the phase field method in driving flow from complex boundaries. In the -proposed project, we apply this framework to perform concurrent simulations of the gas phase with -the phase field model, resolving the kinetics and flame structure as driven implicitly by the order -parameter evolution. The scope of this goal is to resolve the gas phase only well enough to faithfully -capture the heat flux and momentum flux (tractions and pressure) onto the solid phase. However, -the framework will be readily generalizable for coupling to other, state-of-the-art gas-phase solvers. -Goal 3: Agglomerate advection. Agglomerates of aluminum, once formed, may detach from the -solid phase to be advected with the flow field. This presents a unique set of modeling challenges due -to the implicit interface representation. We propose a novel modeling scheme to effect this behavior -that is twofold: (i) topological analysis of the agglomerate fields using a surrogate simplicial -complex, and (ii) construction of overset grids to move particles in response to the flow field while -retaining a Lagrangian reference frame for simulating burn behavior. Goal 4: Mechanical damage -modeling. Initiation of burn can happen spontaneously due to mechanical damage, and damage -mechanisms such as delamination or fracture can result in unexpected, dangerous increases in -burn rate. Mechanical damage can occur as a result of loading prior to burn, or during burn due to -thermal and mechanical loads from the gas phase. Previous work led to the capability to simulate -mechanical effects during the burn simulation, enabling bidirectinoal coupling. This part of the -work will extend the damage modeling capabilities through improved viscous models, modeling the -plastic response of the fuel-binder interface, and improving the phase field fracture model. Goal 5: -Systematic study of realistic mesostructures. A substantial advantage of the proposed approach is -its ability to account for entirely arbitrary mesostructures. Whereas prior work focused more on -idealized systems, this project will focus on analysis of experimentally observed structures.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 14, 2024
- Source ID
- N000142512029
Entities
People
- Brandon Runnels
Organizations
- Iowa State University
- Office of Naval Research
- United States Navy