Characterization of the inductively coupled plasma (ICP) torch at Plasmatron X facility developed by Center for Hypersonics & Entry Systems Studies (CHESS) was performed means optical emission spectroscopy (OES). OES provides a noninvasive method identifying both atomic and molecular species within jet without physically perturbing flow. Additionally, experimental spectra can be compared to simulated provide estimates gas temperature. In this work, we present preliminary results...

View Video Presentation: https://doi.org/10.2514/6.2023-1338.vid Inductively coupled plasma wind tunnels accurately replicate the harsh conditions that hypersonic vehicles experience during atmospheric reentry phase. With ability to reproduce aerothermal heating and chemistry of flight, phenomena such as gas-surface interactions, heat shield ablation response, aero-optics, non-equilibrium can be investigated in a pristine flexible test environment. This paper describes new Plasmatron X...

Direct simulation Monte Carlo (DSMC) is an essential tool in the modeling of spacecraft atmospheric entry. The accuracy transport processes DSMC simulations depends on collision cross section parameters used to model particle interactions. In this work, we provide a comprehensive collision-specific Variable Soft Sphere (VSS) parameter database for accurate properties DSMC. A Nelder–Mead optimization scheme find optimized VSS from integrals, which are acquired either high-fidelity literature...

A systematic approach for calibrating the direct simulation Monte Carlo (DSMC) collision model parameters to achieve consistency in transport processes is presented. The DSMC cross section are calibrated high temperature atmospheric conditions by matching integrals from against ab initio based that currently employed Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) and Data Parallel Line (DPLR) computational fluid dynamics solvers. parameter values computed widely used Variable...

This work discusses the development of a multi-physics modeling framework for Inductively Coupled Plasma (ICP) wind tunnels. As opposed to monolithic approach, separate in-house solvers are considered deal with different parts complete model. The flowfield is modeled using hegel, finite volume solver non-equilibrium plasmas. simulation electric field and thermal Protection System (TPS) material sample accomplished via element (flux pato, respectively). three tools coupled preCICE library....

A general approach for achieving consistency in the transport properties between direct simulation Monte Carlo (DSMC) and Navier-Stokes (CFD) solvers is presented five-species air. Coefficients of species diffusion, viscosity, thermal conductivities are considered. The coefficients that modeled CFD often obtained by expressions involving sets collision integrals, which from more realistic intermolecular potentials (i.e., ab initio calculations). In this work, self-consistent effective binary...

Ion beam irradiation has recently emerged as a versatile approach to functional materials design. We show in this work that patterned defective regions generated by ion of silicon can create phonon glass electron crystal (PGEC), longstanding goal thermoelectrics. By controlling the effective diameter and spacing between regions, molecular dynamics simulations suggest reduction thermal conductivity factor $\approx$20 is achievable. Boltzmann theory shows thermoelectric power remains largely...

Abstract Vibrational energy transport in disordered media is of fundamental importance to several fields spanning from sustainable biomedicine thermal management. This work investigates hybrid ordered/disordered nanocomposites that consist crystalline membranes decorated by regularly patterned regions formed ion beam irradiation. The presence the results reduced conductivity, rendering these systems interest for use as nanostructured thermoelectrics and device components, yet their...

A vibrational state-specific model for dissociation and recombination reactions within the direct simulation Monte Carlo method is introduced to study energy level dynamics of O2 + O system. The state-resolved cross sections relaxation are obtained from a rotationally averaged quasi-classical trajectory database based on Varandas Pais O2( 3Σg−)+O( 3P) potential surface. two-step binary collision framework outlined characterize probabilities, which constrained by detailed balance orbiting...

View Video Presentation: https://doi.org/10.2514/6.2022-1501.vid Reentry and hypersonic vehicles are exposed to high temperatures during flight that require the use of thermal protection systems protect internal structure, payload, crew. Simulating response a system different conditions provides time dependent, spatial information for all regions material, but such simulations difficult perform accurately can incur large computational expense geometrically thermochemically complex materials....

The influence of nitrogen on the oxidation behavior hot-pressed zirconium carbide was investigated using a flow-tube furnace at temperatures ranging from 1000 to 1600 °C. Mass gain, oxide formation characteristics, and transitions were evaluated various experimental conditions. Differences in across range show both kinetic microstructural dependence with implications pointing this materials efficacy ultra-high temperature applications. Results suggest that above 1400 °C, although mechanisms...

A general approach for constructing finite rate surface chemistry models using time-of-flight (TOF) distribution data acquired from pulsed hyperthermal beam experiments is presented. First, a detailed study performed with direct simulation Monte Carlo (DSMC) to analyze the TOF distributions corresponding several types of reaction mechanisms occurring over wide temperature range. This information used identify and isolate products formed through different angular distributions. Next,...

Viscous drag reduction on a submerged surface can be obtained both in the limit of an unbroken gas film coating solid and nanobubble or perhaps microbubble regime when air layer is created with superhydrophobic coatings. We examine intermediate bubble size trapped-bubble array (TBA) formed tap water environment using electrolysis to grow maintain bubbles thousands millimeter-sized holes surface. show that even though tension sufficient stabilize TBA against hydrostatic shear forces beneath...

A new set of continuum breakdown parameters, rigorously derived from Generalized Chapman-Enskog theory, to capture regions strong thermal and chemical nonequilibrium for high speed, chemically reacting flows is presented. Detailed analysis shows that reactions can indirectly contribute via diffusion fluxes.

Classical molecular dynamics calculations were used to investigate the formation of defects produced during irradiation energetic ions on silicon. The aim this study was characterize nature and defective regions formed through ion establish a connection between parameters, lattice defect configurations, resulting modified thermal conductivity characterized according total number generated, size density region, longitudinal radial distribution along impact path. In addition, clustering into...

The purpose of the present work is to investigate plasma characteristics (e.g., three-dimensionality, stability, turbulence) Plasmatron X facility using a state-of-the-art multi-physics computational framework developed at Center for Hypersonics and Entry Systems Studies (CHESS) University Illinois Urbana-Champaign. modeled under Local Thermodynamic Equilibrium assumption. flow governing equations (i.e., Navier-Stokes) are discretized in space based on cell-centered finite volume method....

The influence of nitrogen on the oxidation behavior hot-pressed zirconium carbide was investigated using a flow-tube furnace at temperatures ranging from 1000 to 1600 {\deg}C. Mass gain, oxide formation characteristics, and transitions were evaluated various experimental conditions. Differences in across range show both kinetic microstructural dependence with implications pointing this materials efficacy ultra-high temperature applications. Results suggest that above 1400 {\deg}C, although...