Study of the Afterbody Radiation during Mars Entry in an Expansion Tube

Gu, Sangdi; Morgan, Richard G.; McIntyre, Timothy J.

doi:10.2514/6.2017-0212

Cited by 23 publications

(14 citation statements)

References 11 publications

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“…As was the case with experiments performed by [45], a cold gas driver configuration for X2 (see Figure 16) was recommended to provide the low enthalpy condition, where the helium driver gas is filled isothermally from a high pressure reservoir. A pressure rise occurs within the driver chamber until the primary diaphragm ruptures.…”

Section: Low Enthalpy Conditionmentioning

confidence: 99%

“…Letting state 1 be equal to the 4.0 km/s test condition from [45], and state 2 be equal to intended test conditions for this experiment: Pa was obtained. This was then input into PITOT as the fill pressure for the gas composition to be used for experiments.…”

Section: Low Enthalpy Conditionmentioning

confidence: 99%

“…This differs to the piston-driven configuration where the piston compresses the driver gas to rupture the primary diaphragm. In order to obtain the shock tube fill pressure, it was recommended to perform a density match with the fill pressure (600 Pa) of the 100% CO2 gas used by Gu et al in the 4.0 km/s test condition [45]. The density match arises from flow continuity:…”

Section: Low Enthalpy Conditionmentioning

confidence: 99%

“…Two conditions have been proposed for the in the design of the experiment; a low enthalpy condition modified from Gu et al [45], and a high enthalpy condition ideally suited for the X2 configuration at the time of this experiment. Both conditions are at low speeds where radiative heat transfer is not the highly dominant mode, however they should be considered as proof-ofconcept conditions before experiments with faster flows can be conducted.…”

Section: Test Conditionsmentioning

confidence: 99%

“…Along with this shock tube fill pressure, other parameters from the 4.0 km/s test condition were obtained from [45]: With these assumptions, the answers (see Table 4) are considered as an approximation to the conditions encountered over a 40º cone head in the test section, and throughout the expansion tube. For the output script from PITOT, refer to Appendix B.1.…”

Section: Low Enthalpy Conditionmentioning

confidence: 99%

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The effects of surface catalycity on spacecraft re-entry heat transfer

Little¹

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After identifying inefficiencies within the quantification of re-entry heat flux and the potential for an expanded capability of the X2 expansion tube, a study into the effects of surface catalycity on re-entry heat transfer was conducted. This led to an experiment design which: identified a method to heat a model to 1100 K;  designed, manufactured and bench tested a proof of concept model;  proposed experimental test conditions; and  proposed optical techniques to measure the heat transfer.A pre-heating method using the resistivity of test materials was chosen for experiments, as it provided a fast and effective way to reach temperatures up to 2350 K. Utilising this pre-heating method was an axisymmetric cone model mostly made of copper, with a 'catalytic insert' component (either stainless steel or graphite) intended to be used as the surface of interest for the measurement of surface catalycity effects.High enthalpy and low enthalpy test conditions were developed for the experiments, which were expected to provide operational flexibility and experimental comparison between different species number densities. To measure flow effects from these conditions, such as heat transfer to the model, a two colour technique and infrared pyrometry technique suggested. The infrared pyrometry method was recommended over the two colour method due to possible charge bleeding effects and a better sensitivity for the infrared photodetectors.Bench tests revealed the model reached a maximum temperature of 514 K after 30 s. This was supported by finite element analysis, and was attributed to a high contact area and low length.Therefore, it was suggested that the model be redesigned to incorporate a lower contact area and higher length. Proof of concept bench tests showed that this would enable the model to reach the desired temperature of 1100 K within 30 s.From this investigation, it was considered feasible that the X2 super-orbital expansion tube can be used to test the influence of surface catalycity on heat transfer; however, findings from bench testing showed that the model must be redesigned before expansion tube testing can begin.Future work in this topic was also suggested in modifying Eilmer 4 for use in numerically analysing surface catalycity effects, as well as the use of silica and ceramic surface coatings.ii AcknowledgementsThe completion of this project would not be possible without the guidance and support of many people who I have met along the way.My colleagues undergoing their PhD down in the X-Labs -Ranjith Ravichandran, Sangdi Gu, Steven Lewis and Chris James -thanks for assisting with the project in various ways with your help with PITOT, SPECAIR, bench testing, and procurement of optical equipment. A special thanks to Ranjith for being my go-to bible for all things Abaqus.The staff in the Faculty Workshop Group for assisting with the creation of the proof-of concept model -thanks for the final touch ups you were more than happy to make to the model before bench testing.Everyone out at USQ Toowoom...

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Section: Low Enthalpy Conditionmentioning

confidence: 99%

Section: Low Enthalpy Conditionmentioning

confidence: 99%

Section: Low Enthalpy Conditionmentioning

confidence: 99%

Section: Test Conditionsmentioning

confidence: 99%

Section: Low Enthalpy Conditionmentioning

confidence: 99%

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