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Kyle Daniel (Sandia National Labs)09/09/2024, 16:10High speed facilities, flight testing and propulsion
Background
This study uses spatially resolved optical emission spectroscopy (OES) in the 205–265 nm range to measure nitric oxide (NO) in hypersonic shock layers over cylinder and wedge geometries in the Sandia Hypersonic Shock Tunnel (HST). The measurements, taken in regions of rapid flow expansion, are fit with NASA NEQAIR and Sandia SPEARS codes to extract NO rotational and vibrational...
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Mr Shubham Thirani (University of Illinois Urbana-Champaign)09/09/2024, 16:35
Background of the study
Optical emission spectroscopy (OES) is a valuable tool to gather information about complex thermochemical processes that take place in hypersonic flowfields. Furthermore, optical emission data plays a vital role in the validation of high-fidelity thermo-chemical models used to numerically simulate these flowfields. This work is part of an ongoing study at the Sandia...
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Maïlys Buquet09/09/2024, 17:00High speed facilities, flight testing and propulsion
Introduction
Atmospheric entry leads to extreme heat flux onto the flight vehicle’s surface due to the high enthalpy of the surrounding flowfield. Currently, thermal protection systems are severely oversized which makes vehicles too heavy,restricting performance and payload capacity. One large source of uncertainty is thermochemical non-equilibrium, which has been shown to have a strong...
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Prof. Ronald Hanson (Stanford University)10/09/2024, 16:30High speed facilities, flight testing and propulsion
The acquisition of laser, detector, optical, mechanical, and electronic hardware has supported the ongoing development and application of sensor strategies for the time-resolved measurement of species concentrations, state populations, and non-equilibrium gas temperatures within the NASA Ames Electric Arc Shock Tube (EAST) facility using tunable diode laser absorption spectroscopy (TDLAS)....
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Jesse Streicher (Stanford University)10/09/2024, 16:55High speed facilities, flight testing and propulsion
A multi-year effort has led to a set of advanced UV absorption diagnostics, which probe vibrational populations of O2 and NO in the nonequilibrium gas behind strong shock waves in air. The recent advancements in spectroscopic modeling, ultraviolet (UV) laser availability, and high-temperature shock-tube experiments, like those of this study, have enabled the development of...
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Elijah Jans (Sandia National Labs)11/09/2024, 15:55High speed facilities, flight testing and propulsion
Background of the study
Reflected shock tunnels are an excellent tool for studying high-temperature, hypersonic problems such as boundary layer transition, ablation, and shock-induced flow separation. These phenomena are known to be sensitive to the thermochemical state of the tunnel freestream. Although shock tunnels are a mature technology, much uncertainty in the tunnel freestream...
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Dr Divek Surujhlal (German Aerospace Center (DLR))11/09/2024, 16:15High speed facilities, flight testing and propulsion
Background
The development of re-entry aerodynamic configurations requires examination of surface heat flux. Surface heating due to radiation at high-enthalpy stagnation conditions has been shown to comprise a significant portion of the total measured surface heat flux on re-entry configurations [1] [2]. Earlier studies in high-enthalpy flows on blunt sphere-cones [3] and capsules [4]...
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Hiroki Sakamoto (Tohoku University)11/09/2024, 16:35High speed facilities, flight testing and propulsion
Background of the study
An expansion tube is one of the ground-based experimental facilities that can generate a high-enthalpy hypersonic flow. A standard expansion tube consists of a compression tube, a shock tube, an acceleration tube, and a test section. In the expansion tube, the acceleration tube at extremely low pressure is connected to the shock tube with a thin diaphragm. The...
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Andrea Fagnani (Oak Ridge Associates Universities at NASA Ames Research Center)11/09/2024, 16:55High speed facilities, flight testing and propulsion
Background
The Electric Arc Shock Tube (EAST) at NASA Ames Research Center produces hypersonic shock waves for validation and improvement of non-equilibrium chemical kinetics and radiation models relevant to atmospheric entry flows. The main experimental technique employs four spectrometers, capable of achieving simultaneous spatially resolved emission spectra of the radiating gas from the...
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Samuel Lock (The University of Queensland)12/09/2024, 11:10High speed facilities, flight testing and propulsion
Background of the study
This work demonstrates a versatile optical system capable of providing simultaneous radiation measurements from the vacuum ultraviolet (VUV) to the mid-wave infrared (MWIR). The system consists of several easily swappable configurations that aim to not only minimise experimental setup and alignment time but also increase the scientific output of the X2 expansion...
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Mragank Singh (University of Queensland)12/09/2024, 11:35High speed facilities, flight testing and propulsion
Background of the study
Mars has been the major focus of space exploration and interplanetary travel next only to Earth. The current design process of thermal protection systems for Mars atmospheric entry has large tolerances and uncertainties, which result in the excessive mass of heat shield. One major contributing factor to the uncertainties is the lack of understanding of backshell...
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Mario Lino da Silva (Instituto de Plasmas e Fusão Nuclear - Instituto Superior Tecnico)12/09/2024, 12:00High speed facilities, flight testing and propulsion
ESTHER is a two stage shock-tube. It comprises a 1.6m length and 200mm diameter combustion driver where He/H2/O2 and N2/H2/O2 mixtures are injected by an automated gas filling system at initial pressures up to 100bar. These mixtures are ignited through a Nd:Yag laser shooting on the back plate through a thick sapphire window, reaching...
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Brett Cruden (AMA Inc/NASA Ames)12/09/2024, 15:45High speed facilities, flight testing and propulsion
The Electric Arc Shock Tube Facility (EAST) at NASA Ames Research Center is a well established shock tube facility for quantifying shock layer radiation phenomena. First operated in 1965, EAST consisted of an arc driver into a 10 cm (4”) diameter stainless steel driven tube. A second stainless steel 60 cm (24”) diameter tube, utilizing the same driver, was installed in 1971. The 24” tube...
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Maïlys Buquet12/09/2024, 16:15High speed facilities, flight testing and propulsion
Introduction
The complexity of the flow field encountered around re-entering vehicles poses significant problems to the design of spacecraft thermal protection systems. One large source of uncertainty is linked to thermochemical non-equilibrium. Ground testing is conducted to generate flows similar to those encountered in flight, replicating the essential features of non-equilibrium flows....
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Mr Aaron Kennedy (University of Oxford)12/09/2024, 16:40High speed facilities, flight testing and propulsion
This paper shows the results of an emission spectroscopy test campaign completed in Oxford’s T6 free piston driven Shock tube. Ablative thermal protection systems have proven to be a common option utilised on spacecraft returning to earth in the brief time mankind has been conducting space missions. The pyrolysis gasses produced by ablative heat shields while undergoing heating from an earth...
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