Computation of air chemical equilibrium composition until 30000K - Part I
doi: 10.5028/jatm.2011.03021011

Carlos Alberto Rocha Pimentel*
Federal University of ABC
Santo André/SP – Brazil
carlos.pimentel@ufabc.edu.br

Annibal Hetem Jr.
Federal University of ABC
Santo André/SP – Brazil
annibal.hetem@ufabc.edu.br

*author for correspondence

Abstract:
An algorithm was developed to obtain the air chemical equilibrium composition. The air was considered to be composed of 79% N2 and 21% O2, and the models are 5 chemical species, N2, O2, NO, N, O, NO+, e-, respectively. The air chemical equilibrium composition is obtained through the equilibrium constants method and it was used the Absolute Newton method for convergence.
The algorithm can be coupled as a subroutine into a Computational Fluid Dynamics code, given the flow field over an atmosphere reentry vehicle where, due to high velocities, dissociative chemical reactions and air ionization can occur. This work presents results of air chemical equilibrium composition for pressures of 1, 5, 10, 50 and 100 atm in a temperature range from 300 to 30000K.

Keywords:

Air composition, Nitrogen chemistry, High temperature, Chemical equilibrium problem, Absolute Newton method.

J. Aerosp.Technol. Manag., São José dos Campos, Vol.3, No.2, pp. 111-126, May-Aug., 2011
Received: 15/03/11
Accepted: 01/06/11