Discrete ordinates method in the analysis of the radiative transfer in high intensity discharge lamps

This paper deals with radiation transfer in cylindrical high pressure discharges for which local thermodynamic equilibrium can be assumed. An S-N approximation (a set of N discrete directions) of the discrete ordinates method is used to solve the radiative transfer equation. A summary of the basic equations and numerical formulations is given in order to calculate the spectral intensities and then to evaluate radiative flux and net emission coefficient. Also, the net emission coefficient is described by a semi-empirical formula which contains terms representing the generation and absorption of radiation. The results are presented for a typical high pressure mercury discharge commonly used as a light source.