Thermochemical model of СО2 +N2 mixture at high temperatures

Abstract

Thermochemical model for gas phase and heterogeneous processes taking place in high temperature gas mixtures modelling Martian atmosphere is presented. Reaction rates for gas phase reactions as well as mixture transport properties were selected on the basis of analysis of large amount of data presented in the literature. In order to study interaction of high temperature gas mixture referring Mars atmosphere (mixture of carbon dioxide and nitrogen-CO2(97%)+N2(3%)) with different materials and development of physical model of this kind interactions a number of experiments was conducted in 1 MWt RF-plasmatron using three samples with different catalytic properties (with respect to CO2 plasma species recombination): silver, quartz and copper at two specific levels of flow enthalpy of 9 and 13.8 MJ/kg (corresponding to entry velocities of V = 4.24 and 5.25 km/s) and several values of total pressure within the range of 10-80 mbar. These test conditions corresponds to two high-altitude points of steep (stormy) entry trajectory of the EXOMARS probe developed in cooperation between European Space Agency (ESA) and Russia. Validation of the developed model was made on the basis of comparison between computational results and measurements of heat fluxes and total and static pressure differences around watercooled probes and intended experiments on heat transfer of a model made of glasses reinforced plastics in the flow of carbon dioxide and nitrogen mixture heated in the RF plasma torch.