The improvement of prediction accuracy for rarefied aerodynamics is one of the important factors for space missions. In order to improve rarefied aerodynamic prediction, rarefaction and condensation effects have been investigated experimentally and numerically in this work. Pitot pressure measurements for N 2 nozzle flows have been carried out in the hypersonic rarefied wind tunnel (HRWT). The rarefaction phenomenon was found to impact the measurements, and thus, we have developed a rarefaction

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... model using a bridging function, which represents the rarefaction phenomenon well on pitot pressure for hypersonic rarefied flows in HRWT. In addition, condensation effect has been analyzed for N 2 and CO 2 nozzle flows in the HRWT test section. Although condensation does not impact rarefied aerodynamic measurements for N 2 , stagnation temperature should be higher than 700 K for CO 2 to generate hypersonic rarefied flows for M > 10, Kn > 0.1 and reduce the risk of condensation phenomenon.