Experimental and Theoretical Simulation of Heterogeneous Catalysis in Aerothermochemistry (a Review)

Abstract

The design of aerospace vehicles has required the solution of radically new scientific and technological problems. One of the important problems has been to create reusable heat shield materials. In [1, 2] information concerning the methods and results of solving these problems, including the development of composites from ultrathin quartz fibers and carbon-carbon materials for the "Buran" orbital vehicle heat shield, was presented. The basic thermophysical characteristics of these materials include both the rate or probability coefficients of heterogeneous nitrogen and oxygen atom recombination and the accommodation coefficients of energy recombination at high surface temperatures. In the present paper the experimental and computational aspects of determining these parameters, which are also of interest for new heat shield materials for future space transport systems, are discussed.

Enthalpy Characterization and Assessment of Copper Catalysis Determination in Inductively Coupled Plasma Facility

“…However, most of this data comes from different methods to compute the recombination coefficient and Kovalev et al 13 already pointed out contradictions in catalytic data for high-catalytic materials. The testing campaign presented below consolidates a methodology for an in-house estimation of Cu catalysis.…”

Molecular Physics of Elementary Processes Relevant to Hypersonics: Atom-Molecule, Molecule-Molecule and Atoms-Surface Processes

“…On the contrary, the second type of materials are, instead, expected to accommodate high heating loads and rates by means of mass losses and phase changes. Two coefficients (i.e., γ i and β i ) are used to suitably quantify the wall catalytic efficiency in typical computer fluid dynamics (CFD) simulations of the aerothermodynamics of these hypersonic flights [5]. The catalytic recombination coefficient ( γ i ) is usually obtained from the recombination probability of the i th atomic species to form diatomic molecules on the surface while the chemical energy accommodation coefficient ( β i ) represents the ratio of energy released to the surface per atomic recombination with respect to the maximum energy transferable.…”

“…This is due to both homogeneous [3,4] and heterogeneous [5,6] processes occurring around and at the surface of the vehicle, respectively. Such processes may be reactive (with production of new species and exchange of energy) or non reactive (with exchange of energy only).…”

Simulation of oxygen atom heterogeneous recombination on Al2O3fromab initioapproach

“…The conventional approach used to describe and understand heterogeneous catalysis has so far relied on kinetics or phenomenological models [2]. Such models lend themselves to faster and relatively inexpensive application in the computational §uid dynamics (CFD) codes calculating heat §uxes to space vehicles.…”