Mikhail I. Yakushin

Study of Quartz Surface Catalycity in Dissociated Carbon Dioxide Subsonic Flows

The stagnation point heat transfer from subsonic dissociated carbon dioxide flows to quartz and cooled metallic surface has been studied experimentally and numerically. The experiment was performed by using the induction plasmatron of 100 kW power at pressure 0.1 atm in the wide enthalpy range 14.4-38.5 MJ/kg. The numerical simulation included the computations of the carbon dioxide plasma flows in the plasmatron discharge channel, the flows around the model and within nonequilibrium boundary layer. The data on the effective efficiency of catalytic recombination reactions O + O -» 02 and CO + O -» CO2 on quartz surface have been obtained at the surface temperature range 390-1470 K from comparison of experimental and numerical data on the heat transfer. It is established that effective catalycity of quartz surface in dissociated carbon dioxide flows is quite similar to the data obtained in dissociated pure oxygen flows.

Determination of the Effective Probabilities of Catalytic Reactions on the Surfaces of Heat Shield Materials in Dissociated Carbon Dioxide Flows

The effect of heterogeneous catalysis on the heat transfer to cold and heated surfaces in subsonic dissociated carbon dioxide jet flows is studied experimentally, using a 100 kW inductive plasma generator, and simulated numerically. The effective probabilities of the heterogeneous reactions CO + O → CO2 and O + O → O2 on molybdenum (Tw=300 K) and quartz (Tw=470–620 K) surfaces, the Buran heat shield tile coating (Tw = 1470—1670 K), and two oxidation-resistant carbon-carbon coating materials (Tw=1420—1840 K) are determined by comparing the experimental and calculated data on the heat fluxes at the stagnation point of models at a pressure of 0.1 atm.

Mathematical Models for Plasma and Gas Flows in Induction Plasmatrons

High frequency induction (electrodeless) plasmatrons provide the wide possibilities for modeling of nonequilibrium processes of dissociated gas flow thermochemical interaction with a surface at the conditions corresponding to hypersonic vehicle’s flight in atmosphere at high altitude [1].

Flow and Heat Transfer in Underexpanded Air Jets Issuing from the Sonic Nozzle of a Plasma Generator

We present the results of an experimental investigation and numerical simulation of the gasdynamic structure of underexpanded dissociated-air jets and the heat transfer in these strongly nonequilibrium flows under the test conditions realized in the 100-kW electrodeless VGU-4 plasma generator of the Institute for Problems in Mechanics of the Russian Academy of Sciences (IPM RAS). The flow and heat transfer analysis is carried out on the basis of measurements of the static pressure in the plenum chamber, at the sonic nozzle exit, and on the low-pressure chamber wall, the stagnation pressure on the jet axis using a Pitot tube, and the heat transfer at the stagnation points of water-cooled models placed along the jet axis. The numerical simulation, based on complete Navier-Stokes equations, includes the calculation of (1) equilibrium air plasma flows in the discharge channel of the VGU-4 plasma generator; (2) underexpanded nonequilibrium dissociated-air jet outflow into the ambient space; and (3) axisymmetric jet flow past cylindrical models.