其他摘要：In the process of numerical modelling of combustion of natural gas the estimation of radiation from the products of combustion is fundamental. The RADCAL code [15] is most appropriate for this task, predicting the spectral intensity of the radiation emitted by a non-isothermal volume containing non-uniform concentrations of gases. RADCAL solves the equation of transfer of radiant energy for an entitting and absorbing (nondispersing) medium by considering it formed by a number of volume elements of uniform composition. The calculation of absorption coefficients for each species is done by means of narrow band models and a combination of tabulated spectral properties and theoretical approximations to molecular bands. However, the usefulness of RADCAL is reduced by its high computational cost. in view of this the code needs to be modified to reduce execution times and allow its use in CFD applications. Since the same calculations must be performed many times for each geometry and discretization for the same initial conditions. the absorption coefficients for CO, and H20 were precomputed and stored in look-up tables in frequency bands, for each set of gas pressure and temperature and wall temperatures. in this manner substantial improvements in execution times were obtained depending on the configuration and discretization. Main results are presented in this paper.
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