Capabilities and limitations of existing hypersonic facilities

Gu, Sangdi; Olivier, H.

doi:10.1016/j.paerosci.2020.100607

Cited by 88 publications

(22 citation statements)

References 64 publications

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“…During the re-entry flight of the space vehicle in the earth's atmosphere or the interplanetary atmospheric entry of space vehicles, the flow surrounding the aircraft is characterized by the high-temperature effects such as the dissociation even ionization of the fluid molecules in the flow past hypersonic vehicles 1, 2,3 . The high enthalpy tunnel can duplicate the high flow velocities and subsequently the high-temperature effects 4,5 . For the high enthalpy shock tunnel, the stagnation gas passes through a convergent-divergent nozzle and converts into the hypervelocity free flow, where the stagnation gas is highly dissociated 5,6 .…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: The thermochemical non-equilibrium expansion effects of the high enthalpy nozzle

Shen

Chen

et al. 2020

Preprint

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The high enthalpy shock tunnel can simulate the free-flow speed above 3km/s. The characteristic of the flow is that the kinetic energy of the high enthalpy stagnation gas is high enough to effectuate high-temperature effects such as dissociation even ionization of fluid molecules. The high enthalpy nozzle converts the high enthalpy stagnation gas into hypervelocity free flow. The flow of the high enthalpy nozzle consists of three distinct flow regions: an equilibrium region upstream of the throat, a non-equilibrium region near the throat, and a frozen region downstream of the throat. The study focuses on the conical nozzle, testing thermochemical non-equilibrium expansion effects under the different expansion angle of the expansion section, the curvature radius of the throat, the throat radius, and the convergence angle of the convergent section. A multi-block solver for axisymmetric compressible Navier-Stokes equations is applied to simulate the thermochemical non-equilibrium flow in several high enthalpy conical nozzles. The significant conclusions of this study contain tripartite. Firstly, the thermochemical non-equilibrium effects are sensitive to the maximum expansion angle and throat radius, but not to the radius of throat curvature and the contraction angle. Secondly, as the maximum expansion angle decreases and the throat radius increases, the flow approaches equilibrium. Finally, the maximum expansion angle and the throat radius not only affect the position of the freezing point but also impacts the flow field parameters, such as temperature, Mach number, and species mass concentration.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: The thermochemical non-equilibrium expansion effects of the high enthalpy nozzle

Shen

Chen

et al. 2020

Preprint

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“…Two types of wind tunnels used to facilitate this research is the expansion tunnel [1], and the nonreflecting shock tunnel [2]. Both types of wind tunnels are suitable of generating very high velocity test conditions (> 8 km/s) as they avoid stagnating the test gas, unlike in many of the other configurations [3]. As a result, the nozzles used in these two facilities are purely diverging nozzles, instead of the more common converging-diverging nozzles.…”

Section: Introductionmentioning

confidence: 99%

State-Specific Study of Air in the Expansion Tunnel Nozzle and Test Section

Hao

Wen

2022

AIAA Journal

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Thermochemical nonequilibrium in expansion tunnel nozzles is investigated numerically using a state-to-state description in one-dimension for representative air conditions. Limiting the multi-quantum jumps of VVT transitions to 3 in both N2 and O2 can accurately simulate the nonequilibrium nozzle flow. The reduction of VVT transitions to VT transitions works well. State-to-state modelling of an actual expansion tunnel nozzle condition yielded agreement with the measured static pressure. A study on the influence of different thermochemical excitation in the freestream at the test section shows that the post-shock radiation emissions can differ by more than 50 %. However, the non-Boltzmann distributions in the freestream has no influence. An evaluation of the discrepancy between the twotemperature and state-to-state models shows that the former generally predicts a faster thermochemical relaxation. Furthermore, the state-to-state results indicate that, in general, the molecular species all have a different vibrational temperature.

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“…If the flow establishment time is much longer than the response time of the drag measurement technique, the unexpected response of the test model-support system PLOS ONE can be induced by the unstable aerodynamic force application during the flow development time, which significantly drops the accuracy of the drag measurement. In the present work, the flow establishment time around the test model t e for the attached flows was approximated as follows [5]:…”

Section: Comparison Of the Test Environment Between Drag Measurement ...mentioning

confidence: 99%

“…Impulse facilities are one of the ground test facilities that can simulate a wide range of highpressure and high-temperature supersonic flow conditions with real-gas effects for drag measurements. In recent years, great efforts have been made to develop force measurement techniques with a high accuracy and fast responses for impulse facilities to overcome the limitations in impulse facilities of the short steady test time [5] and non-stabilized structural vibrations inside the model-support system.…”

Section: Introductionmentioning

confidence: 99%

Assessment of drag measurement techniques in a shock tunnel

et al. 2022

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Three force measurement techniques in a shock tunnel, the free-flight, movable-support force balance, and stress-wave force balance techniques were employed, and each technique’s characteristics were assessed. For each force measurement technique, the system setup, data processing method, measurement uncertainties, and applied range of the test model size-flow establishment time were described in detail and compared. For a comparison and discussion, the drag coefficients of a circular pointed cone model with a semi-angle of 18.4° at a nominal freestream Mach number of 6 were measured. As a result, three force measurement techniques yield similar drag coefficients. However, the measurement uncertainties were increased in the order of the free-flight, the stress-wave force balance, and the movable-support force balance techniques. The main causes of the measurement uncertainties were the corner detection uncertainties for the free-flight techniques, and the propagation of the internal or external vibrations for the movable-support and stress-wave force balance techniques. To estimate the appropriate range of the test model size and flow establishment time for each technique’s application, the force measurement systems of the present work and the available literature were compared. As a result of comparative discussion, force measurement environments that can be advantageous for each technique are suggested.

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Capabilities and limitations of existing hypersonic facilities

Cited by 88 publications

References 64 publications

WITHDRAWN: The thermochemical non-equilibrium expansion effects of the high enthalpy nozzle

WITHDRAWN: The thermochemical non-equilibrium expansion effects of the high enthalpy nozzle

State-Specific Study of Air in the Expansion Tunnel Nozzle and Test Section

Assessment of drag measurement techniques in a shock tunnel

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