A5042301591- Gas Dynamics and Kinetic Theory
- Laser-induced spectroscopy and plasma
- Plasma and Flow Control in Aerodynamics
- Heat and Mass Transfer in Porous Media
- Computational Fluid Dynamics and Aerodynamics
- Fluid Dynamics and Turbulent Flows
- Plasma Diagnostics and Applications
- Combustion and flame dynamics
- Heat Transfer and Optimization
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Particle Dynamics in Fluid Flows
- Nanofluid Flow and Heat Transfer
- Heat transfer and supercritical fluids
- Advanced Sensor Technologies Research
- Nuclear Materials and Properties
- Planetary Science and Exploration
- Acoustic Wave Resonator Technologies
- Vacuum and Plasma Arcs
- Space Satellite Systems and Control
- Laser Design and Applications
- Rocket and propulsion systems research
- Advanced ceramic materials synthesis
- Thermal properties of materials
- Particle Accelerators and Free-Electron Lasers
University of Oxford
2017-2025
Science Oxford
2021
Deutsches Elektronen-Synchrotron DESY
2020
Stuttgart Media University
2020
University of Stuttgart
2012-2017
Rieter (Germany)
2015
Technical University of Munich
2009
Porous ultra-high-temperature ceramics (UHTCs) are a candidate group of materials for transpiration cooling hypersonic vehicles due to their exceptionally high melting point, typically above 3000 K. Their operating temperature permits higher amount radiative than that achievable with conventional materials, which reduces the required coolant mass flow rate cool surface. This work experimentally examines internal and external behavior porous UHTC made zirconium diboride purpose cooling. A...
This paper presents results of a system study transpiration-cooled thermal protection systems for Earth reentry. The cooling performance the sustained hypersonic flight and transient reentry blunt cone geometry is assessed. A simplified numerical model used to calculate temperature heat shield. transpiration assessed by calculating overall required coolant mass different steady-state scenarios. Spatially temporally optimized injection presented various conditions. majority on spherical nose...
Abstract This article presents the full operational experimental capabilities of plasma wind tunnel facilities at Institute Space Systems University Stuttgart. The simulation aerothermodynamic environment experienced by vehicles entering atmosphere Earth is attempted using three different facilities. Utilizing facilities, recent improvements enable a unique range flow conditions in relation to other known Recent performance optimisations are highlighted this article. Based on demonstrated...
Abstract The mixing between the coolant and boundary-layer gas downstream of an injector—for transpiration/film cooling—has been extensively studied for turbulent flows; however, only a handful studies concerning laminar exist, particularly in hypersonic flows. In this paper, concentration at wall heat flux reduction transpiring injector flow are experimentally measured examined. Experiments performed Oxford High Density Tunnel Mach 7. A flat-plate model is coated with pressure-sensitive...
Abstract An Argon plasma free jet is investigated using spectrally narrow bandpass filtered high-speed imaging. The images were captured at 16 kHz with an exposure time of 3.9 μs and then calibrated for absolute radiance. exhibited behaviour consistent turbulent shear flow maintains axisymmetric shape. Significant local fluctuations observed over time, growing in strength size as the convected downstream. Assuming thermodynamic equilibrium self-similar free-jet temperature profiles, radiance...
Abstract Three different types of rocks were tested in a high enthalpy air plasma flow. Two terrestrial rocks, basalt and argillite, an ordinary chondrite, with 10 mm diameter cylindrical shape order to observe decomposition, potential fragmentation, spectral signature. The goal was simulate meteoroid ablation interpret meteor observation compare these observations ground based measurements. test flow local mass-specific 70 MJ kg −1 results surface heat flux at the meteorite fragment...
Two-dimensional simulations of transpiration cooling in a laminar, hypersonic boundary layer were performed using the thermochemical implicit nonequilibrium algorithm (TINA): Navier–Stokes solver. Coolant concentration and heat flux results are compared to data obtained from laminar experiments conducted Oxford High Density Tunnel employing flat-plate geometry at Mach 7. TINA successfully predicts mixing rate wall as function streamwise direction for all blowing ratios. The more successful...
This paper presents a comparison of re-entry ight data measured by the NASA/JAXA Hayabusa Observation campaign with numerical calculations and ground testing in NASA Ames Electric Arc Shock Tube (EAST) facility University Stuttgart plasma wind tunnel, Plasmawindkanal 1 (PWK1). The were conducted using URANUS code including thermal chemical non-equilibrium as well radiation transport modeled programs HERTA PARADE. ow eld extended an ablation calculation FABL (Fluid Gravity Engineering...
Determining the source regions of meteorites is one major goals current research in planetary science. Whereas asteroid observations are currently unable to pinpoint most meteorite classes, meteors with camera networks and subsequent recovery may help make progress on this question. The main caveat such an approach, however, that rate falls low, implying meteoritic analogues at least 80% observed remain unknown. Aims: Spectroscopic bolides have potential mitigate problem by classifying...
This paper presents the analysis of optical emission spectroscopic measurements from vacuum ultraviolet (120 nm) to near infrared (960 in a high-enthalpy air plasma flow corresponding superorbital reentry conditions. The have been realized with new experimental setup allowing through bore hole sample. Using commonly applied spectroscopy side, radiation transport along line sight has assessed. allowed determination local ground state densities atomic oxygen and nitrogen branching ratio...
The design of a transpiration-cooled system requires detailed local heat transfer information on and in the vicinity porous injector; however, limited spatially resolved experimental studies exist, particularly hypersonic flows. In this work, experiments were conducted University Oxford’s high-density tunnel at Mach 6.1 both laminar turbulent regimes. Spatially two-dimensional surface measurements acquired by imaging directly downstream two microporous injectors (METAPOR® CE170 zirconia)...
This work presents the development and experimental testing of small-scale slug calorimeter total pressure probes, used to characterize a miniaturized thermal arc-jet facility at University Oxford. instrumentation is determine mass-specific stagnation-point enthalpy an argon plasma flow, allowing for characterization facility. The cold-wall heat flux rate determined using copper calorimeter, featuring pair ceramic insulators minimize losses from slug. Thermal simulations indicate 3.97%,...
An overview of a comprehensive experimental study to investigate ablative materials in high enthalpy air plasma flows including radiation effects is given. Through the application surface thermometry, in-situ recession measurements with photogrammetry, optical emission spectroscopy from vacuum-ultraviolet (120 nm) near infrared wavelengths (950 nm), pyrometry and thermography, complete set data for investigation ablation coupling has been acquired. The paper presents background this project,...
The paper presents the application of non-integer system identification (NISI) method with a focus on analysis system’s impulse response. NISI being first published in 2001 has been applied to very different inverse heat conduction problems. results presented this are new findings developed by considering response as characteristic investigated system. This assumption allows view problems where so far restricted. Examples shown for variable thermophyiscal properties and surface under...
A method is presented allowing for locally resolved emission spectroscopy using a tomographic setup. The approach in this work applied to high enthalpy air plasma flow. resulting data sets allow three-dimensional (3D) representation of the non-symmetric flow field photographs test section and 2D spectrally radiance field. An analysis different exposure times shows that transient fluctuations can result substantial asymmetry approaches symmetry only longer when temporal averaging significant....
Plasma wind tunnel experiments have been performed simulating a Hayabusa reentry trajectory point at 78.8 km altitude with velocity of corresponding to local mass–specific enthalpy and stagnation pressure 2.44 kPa. Ablation–radiation coupling is investigated using carbon preform sample, lightweight phenolic ablator cooled copper. Optical emission spectroscopic measurements in the vacuum ultraviolet (VUV) regime (116–197 nm) conducted through bore hole different samples. UV/VIS spectral range...
The atomic translational temperatures and velocities of a low pressure, high enthalpy air plasma are measured using Fabry–Perot spectroscopy. measurements presented here the first this system at level. sub-picometre resolution unique has allowed accurate temperature velocity species in plasma. detection allows Doppler broadening multiple nitrogen oxygen lines to be simultaneously. Additionally, having two optical paths, one perpendicular flow 45 deg. shift measured.
This paper presents a numerical model that assesses the effect of applying transpiration cooling to both outer wall and substructure high-speed flight vehicle. The porous impulse response analysis for evaluation (PIRATE) code has been extended validated account quasi-two-dimensional lateral heat conduction effects, thereby allowing more complex geometries. enables very fast calculations two-dimensional transient temperature transpiration-cooled thermal protection system suitable first-order...
This paper presents a correlation to obtain the surface species concentration on stagnation point with mass injection for hypersonic flow. The can be used determine recombination heat fluxes and oxidation levels ablatives or actively cooled shields in thermochemical equilibrium It explicitly expresses wall as function of freestream conditions, coolant properties, stagnation-point geometry, revealing direct effect aforementioned parameters desired quantity. method was compared against...