Dependence of Calculated Postshock Thermodynamic Variables on Vibrational Equilibrium and Input Uncertainty

作者：Campbell Matthew F; Owen Kyle G; Davidson David F; Hanson Ronald K

来源：Journal of Thermophysics and Heat Transfer, 2017, 31(3): 586-608.

DOI：10.2514/1.T4952

The purpose of this article is to explore the dependence of calculated postshock thermodynamic properties in shock tube experiments upon the vibrational state of the test gas and upon the uncertainties inherent to calculation inputs. This paper first offers a comparison between state variables calculated according to a Rankine-Hugoniot-equation-based algorithm, known as FROSH, and those derived from shock tube experiments on vibrationally nonequilibrated gases. It is shown that incorrect vibrational relaxation assumptions could lead to errors in temperature as large as 8% for 25% oxygen/argon mixtures at 3500K. Following this demonstration, this article employs the algorithm to show the importance of correct vibrational equilibration assumptions, noting, for instance, that errors in temperature of up to about 2% at 3500K may be generated for 10% nitrogen/argon mixtures if vibrational relaxation is not treated properly. Finally, this article presents an extensive uncertainty analysis, showing that postshock temperatures can be calculated with root-of-sum-of-square errors of better than +/- 1% given sufficiently accurate experimentally measured input parameters.

• 出版日期2017-9