Approximations for hypervelocity nonequilibrium radiating, reacting,and conducting stagnation regions

Nonequilibrium Stagnation-Line Radiative Heating for Fire II

“…It is seen that, except for the 1643 and 1645 s points, the predicted values of the absorbed VUV radiation (αq r - (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)) fall between the αq (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) values in this table are a result of the q total,meas being lower than the predicted super-catalytic convective heating. The non-physical nature of these negative values suggest that the heatshield for this case is more accurately modeled with the non-catalytic assumption, which are shown in Table 5 to result in positive αq (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) values throughout the trajectory. The disagreement at 1645 s between the predicted and inferred values is not surprising, since it was not considered a "prime" data point by Cauchon 2 (although 1637.5 and 1640.5 were not either).…”

“…The absorbed radiative flux refers to the component that is absorbed by the beryllium calorimeter over the entire spectrum. The spectral absorptance of beryllium is reported by 4,5,6,7,8,9,10,11,12,13 . Table 2 lists those studies published since 1984, which are the most relevant to modern studies.…”

“…While Figure 13 implied the importance of the VUV radiation component by showing that it was required to achieve a good comparison between the calorimeter data and predictions, a stronger conclusion may be made regarding the VUV radiation if the comparison between the radiometer data and predictions are included in the discussion. Table 5 achieves this by converting the intensity (between 0 and 6 eV) measured by radiometer (I w,meas (0-6)) to the radiative flux absorbed by the calorimeter between 0 and 6 eV (αq -r,inferred (0-6)), which is then subtracted along with the predicted convective heating from the actual calorimeter measurement q total,meas , resulting in the radiative flux absorbed by the calorimeter between 6 and 18 eV (αq -r,inferred (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)). The subscript "inferred" is used to indicate that the value is a result of the actual calorimeter and radiometer data, along with the predicted convective heating and the ratio between the predicted αq r -(0-6) and I w (0-6) values, labeled β in the table.…”

“…Past studies concerning the accuracy of the tangent slab approximation have concluded that a detailed threedimensional transport calculation produces a flux value about 10 -20% lower than that predicted by the tangent slab approximation 38 . Table 6 presents the values defined in Table 5, except now with both αq -r (0-6) and αq -r (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) multiplied by a factor of 0.85. Only the values that are influenced by this factor are presented in Table 6, with αq (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) now falls between the supercatalytic and non-catalytic "inferred" values.…”

Non-Boltzmann Modeling for Air Shock-Layer Radiation at Lunar-Return Conditions

“…The first of these models, referred to as the 1 st order local thermodynamic nonequilibrium (LTNE) model, was originally proposed by Carlson 8 . It assumed that the excited atomic states were in equilibrium with the ions and electrons, instead of with the ground electronic state of the atom.…”