Plant Fund Scope:(NextGen MatProTech) Hypersonic Modeling for Novel Materials and Systems - Project 8

Research Project 8: Hypersonic Modeling for Novel Materials and Systems UK PIs: Alexandre Martin (PI), Savio Poovathingal (Co-PI) ARL POCs: Daniel Knorr Task 8.1 Rapid Testing and Modeling of Materials in Hypersonic Environments: Material Response and Flow Environment In order to evaluate the performance of new materials in hypersonic environments, it is desired to model them and predict their behavior. To demonstrate that process, existing materials of interest to the Army will be selected, and a property model will be built. A readily available – yet relevant – material, such as C/C, will be used for this initial step. The material properties will either be generated or existing dataset used to build a material model, and this material model will be utilized in the in-house code KATS-MR to simulate the behavior of the material in a high-enthalpy environment. The simulations can also be used to predict how the material would perform in a real flight environment. As opposed to standard state-of-the-art Thermal Protection Systems (TPS) modeling codes, KATS-MR uses the Volume-Averaged Navier-Stokes (VANS) formulation, and thus resolves the full momentum equation for porous media, instead of relying on simplified models such as Darcy’s Law. To improve the accuracy of the material response, modeling of the plasma environment will be performed. To achieve this, chemistry models will be added to the code, as well as additional governing equations (Maxwell equations) to account for Joule heating. ARL Activities Central to the task will be an early visit by the UK hypersonic team (Drs. Poovathingal, Fu and Martin) to ARL to better understand their needs, initiate collaborations, and define interactions. More specifically to this sub-task, discussions with the C/C composite team at ARL will help down-select a material, and potential ARL data sets will be used for material properties and model validations. The initial interactions with ARL will be drive the selection of the material that is to be modeled and evaluated for performance in hypersonic environments. Deliverables Material model for the hypersonic material of interest to the Army. Fluid dynamic solution of the plasma environment for an ionizing gas. Prediction of material behavior in high-enthalpy environment. Fluid dynamic solution of the plasma with Maxwell equations. Preliminary report documenting the technical approach and results. Task 8.2 Advanced Development of New TPS Concept: Transpiration Cooling Through this second task, advanced development of new TPS concept will be pursued. For example, the concept of transpiration cooling could be tested for low-atmosphere (high pressure) hypersonic environments. For such a TPS, a coolant gas is injected through a porous material into the boundary-layer. This technology reduces the heat load to the TPS, thus increasing the envelope of performance for hypersonic vehicles. The heat propagation, as well as the gas-surface interactions, will first be modeled at the micro-scale using direct simulation Monte-Carlo (DSMC). These results will be homogenized and transformed into transport parameters (permeability, tortuosity, porosity) applicable at the macro-scale, and used in the KATS-MR solver. For such an approach, modifications to the solver will be needed so that low-speed boundary conditions can be used. Published experimental results on transpiration cooling systems using porous ultra-high temperature ceramics will be used to validate the numerical approach. This task is envisioned as a high-risk, high-payoff effort and if successful, could lead to novel used of C/C materials for heat shield materials. ARL Activities Central to the task will be an early visit by the UK hypersonic team (Drs. Poovathingal, Fu and Martin) to ARL to better understand their needs, initiate collaborations, and define interactions. More specifically to this sub-task, a novel TPS of interest to the Army will be selected and studied. The environment used for this TPS will be modeled, and the concept of transpiration cooling will be applied to evaluate the potential benefit. Deliverables Preliminary report documenting the technical approach and validations results, Task 8.3 Advanced Development of New TPS Concept: Differential Recession Rates for C/C Composites For this third task, detailed physical phenomenon that is key to high temperature materials will be explored. Primarily, this task would focus on building multi-scale physics-based models of materials interacting with hypersonic environments. As an example of such phenomena, the complex interaction between the carbon fibers, matrix/binder and the high-temperature gas in the hypersonic flow could be studied. The voids formed from manufacturing, differences in the densities of the fibers and matrix, the crystalline/amorphous structures of the fibers and matrix, diffusion of reactive gases, and effusion of oxidized products all combine together such that the fibers and matrix ablate at different rates resulting in microstructural variations in the composite material as they ablate. The difference in ablation rates, increases the area available for oxidation reactions, traps heat, can affect the flow field (early transition), and leads to a cascading effect, where one mode of degradation feeds into the other. In hypersonic environments, these are catastrophic, and failure will be rapid. The activities will be performed using in-house computational tools that have been optimized to investigate micro-scale reactive processes at high temperatures for various materials. The microstructural architecture is imported into the computational tools through high-resolution micro-tomographic imaging. Materials will be ablated in a high-temperature oven, thermogravimetric analyzer (TGA), or obtained from experimental partners. Pre and post test samples will be imaged or obtained directly from the ARL team, and in-house tools will be used to infer relative reactivities of the fiber and matrix. Multi-scale models will be developed from the detailed microscale analysis to capture the differential recession at the macroscale. The study will help understand the features of C/C composites that could lead to uncontrolled ablation, which needs to be avoided to prevent failure. [PS1] ARL Activities Central to the task will be an early visit by the UK hypersonic team (Drs. Poovathingal, Fu and Martin) to ARL to better understand their needs, initiate collaborations, and define interactions. More specifically to this subtask, ARL will be consulted to choose a material, and provide samples to be used to perform the micro-tomography imaging. Depending on available information from the ARL team, tomographic imaging may not be required as the pre and post test images may already be available. Deliverables High resolution imaging of the material of choice. A multi-scale model of the performance of material in hypersonic environments. Characterization of pre and post test samples and their ablated microstructures. [PS1] Let me know if I should expand more on: why care??