State to state vibrational kinetics in the boundary layer of an entering body in earth atmosphere: particle distributions and chemical kinetics

Abstract

Both gas-phase kinetic processes and heterogeneous surface processes assume an important role in affecting the flow field in the boundary layer of re-entry vehicles. In this work a N 2 , N, O 2 , O, NO mixture hitting either a non-catalytic surface or a SiO 2 partially catalytic one has been theoretically analysed. Vibrational distributions far from equilibrium have been obtained both for different surface conditions and for different boundary layer edge temperature and wall temperature pairs and finally for different flow residence times.

An evaluation of the effect of the dissociative attachment of vibrationally excited H2on primordial universe chemistry

“…Such a process leads to a vibrational distribution that could be represented by a superposition of a Boltzmann distribution at low temperature, which accounts for the large quantity of molecular density and mean energy, and a thermalization curve connected with the lifetime of a molecule in the vibrational level v during its degradation towards thermal energies. Such recombination tails have been found by rigorous calculations of different gas systems (N 2 , O 2 ) (Armenise & Capitelli 2005). While these calculations are not yet available for hydrogen, we observe that the supra-thermal tails found for other gases can be roughly represented by a slowly decreasing function of v, such as 1/(1 + v).…”

N2, O2, NO state-to-state vibrational kinetics in hypersonic boundary layers: The problem of rescaling rate coefficients to uniform vibrational ladders

“…In the framework of the Earth re-entry problem, a deep investigation of a five species (N 2 /N/O 2 /O/NO) hypersonic boundary layer was carried out in the past by our research group [1][2][3][4]. The stateto-state kinetic model was adopted.…”

“…For the N 2 and O 2 molecules all the vibrational levels were considered as different species, which is the peculiarity of the state-to-state model, whereas the NO molecule was not vibrationally detailed, i.e. it was considered as a unique species [1][2][3][4].…”

“…In this way dissociation-recombination reactions are VV and VTm processes involving this pseudolevel [1][2][3][4]. About reactions (10.a) and (10.b) it is worth noting that they are the same one written in two different ways: in the first case (Eq.…”

Consistent Comparison of Macroscopic and State-to-State Kinetics in Hypersonic Flows

“…1,2 In last years the state-to-state approach, commonly used in weakly ionized gas modelling, [3][4][5] has been applied to hypersonic gas dynamics. [6][7][8][9][10] It consists in solving the balance equation for all the internal states of the degree of freedom (usually vibration) that is not in equilibrium. The internal (vibrational) temperatures obtained by state-to-state calculations and related to the first energy levels reproduce the results obtained by macroscopic models.…”