OCR Text |
Show emissions control requirements and the large number of design variables. Specifically, in this app l ication modelling has helped Quantitatively determine such basic design parameters as the overall geometry, inlet and outlet aerothermochemical profiles, gas and particle residence times, injector characteristics. In addition, estimates of fuel utilization, pressure and heat loss and slag separation were obtained, thereby allowing detailed design work to proceed. It is also noted from a limited Qualitative/Quantitative evaluation of the predictions generated in this study, as well as extensive critical assessment studies reported in the literature for similar cases, that the various physical submodels employed to describe the relevant phenomena can be claimed, within the framework of their associated assumptions to be sufficiently adequate for engineering purposes. Trends and overall characteristics are predicted correctly. Furthermore, incorporation of refinements concerning the numerical and physical aspects of modelling to yield better local agreement with experiments is no insurmountable problem. New theories of combustion, alternative modelling procedures, etc. can be combined in a comprehensive manner within the basic structure to this end. Thus, in the following are presented some remarks both of a general and specific nature regarding potential shortcomings along with possible solution strategies for some aspects of the model used in this study. Data generated during the course of the hardware development stage of the current program will guide and Quantify efforts in this area. A major concern associated with the use of current models of combustion is that of suitability of turbulence models, developed primarily for simplified two-dimensional (isotropic) isothermal flows, in modelling reacting flows. The ever important problem of accounting for the strong coupling 13 |