TY - JOUR

T1 - Numerical study on abnormal heat flux augmentation in high enthalpy shock tunnel (HIEST)

AU - Ishihara, Tomoaki

AU - Ogino, Yousuke

AU - Ohnishi, Naofumi

AU - Tanno, Hideyuki

N1 - Publisher Copyright:
© 2015 The Japan Society for Aeronautical and Space Sciences.

PY - 2015

Y1 - 2015

N2 - Unexpected heat flux augmentation in a free-piston high-enthalpy shock tunnel (HIEST) was numerically analyzed. Since a previous experimental study implied that the radiation heating from the shock layer caused the augmentation, a three-dimensional thermochemical non-equilibrium CFD code including radiation transport calculation in the shock layer was developed. This calculation was conducted under the following models: 1) Radiation heating from the air species in the shock layer was calculated by a solving radiative transport equation using tangent slab approximation; and 2) Radiation heating from impurities such as carbon soot and metal particulates, which could be included in the upstream test gas, was calculated by assuming the shock layer as a grey body with averaged shock layer temperature for a trial calculation. The calculations were performed at the stagnation enthalpy and stagnation pressure from 7 to 21MJ/kg and 31 to 55 MPa, respectively. For air species radiation, radiative heat flux was too small to contribute heat flux augmentation. On the other hand, for grey body assumption, we could find that abnormal heat flux augmentation could be expected by εσTave4 for an engineering technique, where ε denotes the emissivity ε = 0.132 and Tave4 was the average shock layer temperature.

AB - Unexpected heat flux augmentation in a free-piston high-enthalpy shock tunnel (HIEST) was numerically analyzed. Since a previous experimental study implied that the radiation heating from the shock layer caused the augmentation, a three-dimensional thermochemical non-equilibrium CFD code including radiation transport calculation in the shock layer was developed. This calculation was conducted under the following models: 1) Radiation heating from the air species in the shock layer was calculated by a solving radiative transport equation using tangent slab approximation; and 2) Radiation heating from impurities such as carbon soot and metal particulates, which could be included in the upstream test gas, was calculated by assuming the shock layer as a grey body with averaged shock layer temperature for a trial calculation. The calculations were performed at the stagnation enthalpy and stagnation pressure from 7 to 21MJ/kg and 31 to 55 MPa, respectively. For air species radiation, radiative heat flux was too small to contribute heat flux augmentation. On the other hand, for grey body assumption, we could find that abnormal heat flux augmentation could be expected by εσTave4 for an engineering technique, where ε denotes the emissivity ε = 0.132 and Tave4 was the average shock layer temperature.

KW - Aerodynamic heating

KW - Computational fluid dynamics

KW - Hypersonic flows

KW - Radiation

KW - Shock tunnel

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U2 - 10.2322/tjsass.58.319

DO - 10.2322/tjsass.58.319

M3 - Article

AN - SCOPUS:84946726082

VL - 58

SP - 319

EP - 326

JO - Transactions of the Japan Society for Aeronautical and Space Sciences

JF - Transactions of the Japan Society for Aeronautical and Space Sciences

SN - 0549-3811

IS - 6

ER -