Flame structure and flame stability characteristics of interacting 2D and circular laminar jets in a linear triple burner array.

摘要

Cluster burners, where large numbers of burners are grouped closely together, are emerging as a new technology in the gas turbine industry. The interactions between the burners help to increase combustion stability and reduce harmful pollutant emissions. In addition to the gas turbine industry, multiple-port burners are also found in common cooking ranges, space heaters, and industrial burners. Due to the wide application of this technology, an attempt must be made to fundamentally understand the flame interaction process and to identify the physical parameters that govern it.; In the work presented here, a simple apparatus consisting of three burners placed in a linear array was constructed to fundamentally study the flame interaction process. The linear array and limited number of burners allows the physics to remain tractable. Measurements of the temperature, flame structure (flame height, width, etc.) and the flame stability (lift off height and blow off velocity) characteristics of the flames under interactive modes were made as a function of Reynolds number, interburner spacing, fuel composition, and burner exit plane geometry. Also, in an attempt to validate the experimental results, a theoretical model, based on the solutions to the governing equations of mass, momentum, and species was developed for an isolated jet and was modified to include multiple burner effects. Specifically, the extrapolated multiple burner model was used to define the stages of interaction as isolated (no interaction), individual (weak to moderate interaction), group (strong interaction), and sheath (strongest interaction), similar to the terminology used in droplet combustion.; Results showed that the theoretical model qualitatively predicted the magnitude and trends of the flame structure and flame stability characteristics of the isolated 2D and circular burners. Under multiple flame conditions, flame interaction increased flame height, decreased the maximum flame width to visible flame height ratio, increased blow off velocity, and increased the temperature in the interstitial space surrounding the central flame in the triple burner array.