Development of a Total Enthalpy and Reynolds Number Matched Apollo Re-entry Condition in the X2 Expansion Tunnel

Cullen, Timothy G.; James, Christopher M.; Gollan, Rowan; Morgan, Richard G.

doi:10.1007/978-3-319-91017-8_24

Cited by 2 publications

(1 citation statement)

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“…The value of dci/dx is proportional to ρ for the VT and VVT reactions, and the value of dci/dx is proportional to ρ 2 for the recombination reactions. Since p is proportional to ρ according to the ideal gas law, the aforementioned trends for ρ can also be said for p. In the expansion tunnel, the nozzle inlet pressure typically ranges from around 10 kPa to 100 kPa [94][95][96][97], while the nozzle inlet velocity typically ranges from around 4 km/s to 11 km/s [95,98,99]. Based on these conditions and the discussion on the dependencies of dci/dx, we can see that it is the range of the inlet pressure (an order of magnitude, which is much higher than the factor of 2-3 for the range of the inlet velocity) which would determine the variety of different thermochemical behaviors (equilibrium, frozen, nonequilibrium) that are possible in the expansion tunnel nozzle.…”

Section: Comparison Between 2t and Sts Modelsmentioning

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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