Numerical Study on Convection Diffusion for Gasification Agent in Underground Coal Gasification (UCG). Part II: Determination of Model Parameters and Results Analysis.

The determination methods of the major model parameters are explained in this article, and the upstream weighted multi-cell balance method is adopted to solve the numerical models established. The author also analyzes and discusses the simulated calculation results, which show that, except for very few points in the loosening zone, where the relative calculation error is comparatively high resulting from the low oxygen concentration, the relative calculation error of other points falls between 8% and 19%. Therefore, the calculation value and the experiment value take on a good conformity. The simulated results indicate that the calculation value of the oxygen concentration is a little bit lower than the experiment one. On top of that, with the prolonging of gasification time, in a high temperature zone the change gradient of oxygen concentration for experimental value is bigger than that of the calculation value. The oxygen concentration is in direct proportion to its distance from the flame working face, i.e., the longer its distance is, the higher the oxygen concentration is; otherwise, the lower the oxygen concentration is. [ABSTRACT FROM AUTHOR]