Radial Jet Reattachment Combustion

Abstract

A novel combustion nozzle utilizing flame impingement has been developed from the concept of Radial Jet Reattachment. The RJR concept was emulated because of its high turbulence intensity and enhanced transport properties, which provide more effective combustion and improved impingement heat transfer. The Combustion Jet Impingement Facility was designed and constructed to evaluate these new nozzles under a variety of test conditions. The nozzles were evaluated primarily on the basis of total heat transfer capability. Results also include flame stability criterion, analysis of exhaust gas products, and comparisons to conventional flame impingement nozzle designs. The variables investigated were nozzle-to-plate distance, air flow rate, fuel flow rate, and nozzle air exit velocity. The RJRC nozzles performed very well, generating a stable flame along with high heat transfer rates. The nozzle-to-plate distance strongly influenced flame stability, but had only a modest effect on the total heat transfer rates. Increasing the fuel flow rate produced a significant increase in the total heat transfer, but caused a marked decrease in the efficiency of the process. Increasing air flow rates as well as exit velocities resulted in decreased heat transfer rates. In comparisons with more conventional nozzles, RJRC showed improvements in total heat transfer.