Development of Shock Tube for Ground Testing Reentry Aerothermodynamics

Yamada, Gouji; Suzuki, Toshiyuki; Takayanagi, Hideaki; Fujita, Kazuhisa

doi:10.2322/tjsass.54.51

Cited by 17 publications

(7 citation statements)

References 16 publications

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“…To predict the attainable pressure in the compression tube, the motion and compression of the free piston are investigated as mentioned in Ref. 6. In this analysis, isentropic process is assumed.…”

Section: Hvst Update For High Shock Velocitymentioning

confidence: 99%

Radiation intensity measurement in VUV wavelength region behind strong shock wave for future sample return missions

Takayanagi

Fujita

Ishida

et al. 2014

11th AIAA/ASME Joint Thermophysics and Heat Transfer Conference

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Radiation measurements in VUV wavelength region behind strong shock wave around 14 km/s at 5 Pa and 12 km/s at 30 Pa with air are conducted in Hyper Velocity Shock Tube developed in JAXA Chofu Space Center in order to expect the radiative heating for future sample return missions from Jupiter Trojans and comet surfaces. For high shock velocity, the thickness of the first diaphragm and pressure inside the compression tube are investigated theoretically and experimentally. Calibrated with a Deuterium lamp, the absolute spectral radiances in VUV region are estimated. By setting it at the measurement positions, spectral radiance in VUV wavelength region can be obtained.

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Section: Hvst Update For High Shock Velocitymentioning

confidence: 99%

Radiation intensity measurement in VUV wavelength region behind strong shock wave for future sample return missions

Takayanagi

Fujita

Ishida

et al. 2014

11th AIAA/ASME Joint Thermophysics and Heat Transfer Conference

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“…In order to attain the soft landing of the free piston at the end of the compression tube, pressures inside the air reservoir tank and compression tube are adjusted. 9 After the first diaphragm ruptures because of the high pressure gas generated in front of the piston running toward the first diaphragm, a strong shock wave is generated and propagates through the test gas filled inside the high pressure tube. In the high pressure tube, the shock wave accelerates the test gas.…”

Section: Flow Conditions In Hvet a Theoretical Analysismentioning

confidence: 99%

“…In order to rupture the first diaphragm safety by compressing the gas with the free piston, the pressures inside the air reservoir tank and compression tube are adjusted in accordance with the simple analysis. 9 Once the primary shock wave arrives at the low pressure tube, rupture of the secondary diaphragm induces a second shock wave that propagates into the expansion gas. As a result, a flow with a uniform pressure and speed is achieved through a secondary unsteady expansion wave at the driven and expansion contact surface.…”

Section: A Expansion Tube Developed On the Basis Of Hyper Velocity Smentioning

confidence: 99%

Emission Intensity Measurements around Mars Entry Capsule with a Free-Piston-Driven Expansion Tube

Takayanagi

Nomura

Fujita

2014

52nd Aerospace Sciences Meeting

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In order to estimate the emission intensity around a Mars Entry Capsule, an expansion tube is developed by updated the Hyper Velocity Shock Tube, which has been used for the radiation measurement from VUV to NIR wavelength region behind strong shock wave in Mars simulant gas. By expanded the low pressure tube inside the vacuum chamber, an expansion tube, which is called as Hyper Velocity Expansion Tube, is achieved. The test section, where test models are set, is located at the outlet of the expansion section. The test time and characteristics of the test flow are estimated theoretically and experimentally with air and CO 2 . The flow velocity can be around 6 km/s, which agree with a Mars entry condition. The radiation intensities in air and CO 2 are measured. The shock stand-off distances are mm in air and in CO 2 , respectively. I. Introductionecently, several missions with the entry into the Martian atmosphere have been proposed all over the world. On August 6, 2012, Mars Science Laboratory mission landed the Martian ground successfully. However, the design margin had to be quite large because of the lack of knowledge of the aerothermochemistry. 1 In order to predict the radiation heating during the Martian atmospheric entry, several researchers have investigated these phenomena with experimental and simulated methods. B. A. Cruden, et al, have been measured the emission intensities behind strong shock wave with Mars (96% CO 2 , 4% N 2 ) and Venus (96.5% CO 2 , 3.5% N 2 ) simulant gases at downstream pressures and incident velocities spanning from 0.1-2.0 Torr and 3-12 km/s. 2,3 In our research group, the absolute radiation intensities behind strong shock wave in Martian simulant gas have been measured in our Hyper Velocity Shock Tube. 4 Emission intensities from VUV to NIR region were obtained at 1.0 Torr, 7km/s and 0.1 Torr, 8.5km/s. The absolute spectral radiances from UV to NIR and VUV to UV regions were calibrated with a tungsten halogen lamp and a Deuterium lamp, respectively. CO 4 th positive band in VUV, CN violet in UV and C 2 swan band in VIS were detected. Atomic carbon, nitrogen, and oxygen were also detected. At 1.0 Torr, 7km/s, the flow was achieved in thermochemical equilibrium around 5 mm behind the shock wave, while at 0.1 Torr, 8.5km/s, the flow was totally in nonequilibrium. The observed radiation intensities were same orders of magnitude with the ones measured in EAST facility.Fujita, K., et al., assessed forebody and aftbody heat transfer rates of a small-sized Martian aerocapture demonstrator for the preliminary design study of an aeroshell equipped with light-weight thermal protection system. 5 In the forebody region, a major portion of the spectrum is distributed among VUV and UV

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“…Figure 1 shows a schematic drawing of the spectroscopic measurement system at the test section. The shock velocity at the test section is measured by the double-laser schlieren measurement system (Yamada, et al, 2011). Two laser beams are aligned along the flow direction in line to pass through the test section perpendicularly to the axis of the shock-tube flow.…”

Section: Shock Tube Facilitymentioning

confidence: 99%

Generation mechanism of precursor electrons ahead of a hypersonic shock wave in argon

Yamada

Ago

Kawazoe

et al. 2014

JFST

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Recently, various planetary explorations have been proposed around the world. Now, astronauts are staying in the international space station (ISS) and conducting various space activities. In addition, NASA has a plan to send humans to Mars in the 2030s. Improvement of atmospheric entry flight technology is an important goal to realize these missions. When a space vehicle enters into a planetary atmosphere, a detached shock wave is generated around the body, resulting in the severe aerodynamic heating. The aerodynamic heating is affected by the nonequilibrium processes of thermal relaxation, dissociation, ionization and recombination reactions around space vehicles (Park, 1985). An accurate prediction of the thermochemical nonequilibrium phenomena is necessary for the development of a thermal protection system (TPS). Now, the evaluation of flight environments is carried out by computational fluid dynamics (CFD) simulations (Gnoffo, et al, 1989). The result highly depends on the accuracy of the thermochemical model applied in the simulation. Therefore, the model should be validated and updated to improve the accuracy. Yamada et al. (2012a, 2012b) conducted shock tube experiments in super-orbital entry flight conditions to validate the two-temperature model (Park, 1988, 1989, 1990, 1993) which was widely used to evaluate entry flight environments. The results show that the relaxation process of the electronic excitation mode is much different from the model prediction. To clarify this problem, a numerical analysis was carried out by considering the nonequilibrium process of the electronic excitation mode (Yamada, et al., 2013). It was found that the calculated relaxation process agreed well with the measured one by assuming the generation of electrons ahead of a shock wave. The existence of precursor electrons ahead of shock waves in N2 was confirmed by the triple-probe measurements using a shock tube (Fujita, et al., 2001a, 2001b). In addition, the effect of precursor electrons on the thermochemical nonequilibrium process behind shock waves was numerically

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Development of Shock Tube for Ground Testing Reentry Aerothermodynamics

Cited by 17 publications

References 16 publications

Radiation intensity measurement in VUV wavelength region behind strong shock wave for future sample return missions

Radiation intensity measurement in VUV wavelength region behind strong shock wave for future sample return missions

Emission Intensity Measurements around Mars Entry Capsule with a Free-Piston-Driven Expansion Tube

Generation mechanism of precursor electrons ahead of a hypersonic shock wave in argon

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