OCR Text |
Show of negligible velocity, so that all volatilization occurs in the vicinity of the impact point. Since in most cases of practical interest, the design should ensure maximum burning in suspension, details of particle-wall interaction may not be critical to combustion stability and flow field structure. However, wall reaction can contribute extensively to combustion of large coal particles. As these particles ordinarily dominate residence time requirements for pure suspension burning, they are most effectively burned via wall reactions that provide extended residence time. Finally, there exist issues related to numerical algorithm development to yield enhanced computational efficiency via improved solution procedures. These include advanced finite difference algorithms(13) and improved finite difference solvers(14). Such algorithms have already been t~sted under isothermal conditions(15) but need to be incorporated and tested in two phase reactive flow codes. 4.0 CONCLUSIONS A three-dimensional, multi phase, turbulent, reactive flow code was used extensively in the preliminary design of a slagging coal combustor for utility gas turbine application. The computational model has proved to be an important preliminary design tool, given the engineering constraints imposed on the combustor design, complexity of flow fields generated in this type of combustor, stringent emissions control requirements and the large number of design variables to be determined. Some aspects of the numerical methodology and physical modelling improvements have been tentatively identified. The subscale combustor thus designed is currently being tested; data to be 16 |