Modeling two-phase flow in a swirl combustor. Final report. A. R. A. P. report No. 310

A phenomenological model of flow in a cyclone coal combustor-gasifier is presented. The model predicts how four performance parameters which measure the carbon conversion efficiency, ash separation, pressure drop, and heat losses depend on such design variables as chamber pressure, size and shape, flow rates, and stoichiometry, along with coal particle size and composition. Correct prediction of the performance parameters requires accurate analysis of the coal particle combustion, particle mechanics and fluid mechanics, all of which are coupled in this confined vortex flow. The model is based on assimilating simple approximations to the most important mechanisms governing flow and combustion in the chamber and thus necessarily involves empirical coefficients. Model verification by comparison with laboratory results from Pittsburgh Energy Research Center shows reasonable agreement, but due to the empiricism required in the model further tests are warranted. Model derivation and sensitivity analysis pinpoint the phenomena which are most critical to the performance of a cyclone combustor. Methods for reducing the empirical requirement of the model are discussed and recommendations made for model improvement.