Numerical simulation of cold flow patterns and turbulent mixing in a simplified burner

摘要

The COYOTE computer program was used to simulate the flow field and turbulent mixing near the fuel and air inlets in a simplified burner. The authors report the results of four cold flow calculations that illustrate several interesting phenomena in addition to demonstrating the capabilities of the basic hydrodynamics model and the turbulence model. They also demonstrate some interesting facets of the hydrodynamics of burners. They summarize their findings as follows: (1) two different grids gave vastly different answers, underscoring the importance of assuring grid-independence in numerical solutions; (2) cold flow patterns are much different than reactive flow fields, making it unwise to apply conclusions from the former to the latter; (3) the problem is elliptic, and it is necessary to include the whole furnace in the calculations; (4) the flow patterns exhibited weakly unstable, almost metastable, modes that make it difficult to ascertain when steady conditions have been obtained. The long range goals of this study are to identify parameters that affect the production of NO(sub x) and to discover methods of reducing emissions while maintaining or improving burner efficiency.