Mixing and Combustion Performances of a Baffle-Plate-Type Miniature Confined Multi-Jet

Abstract

The mixing and combustion performances of a baffle-plate-type millimeter-scale confined multi-jet were investigated experimentally by measuring the blow-off limit of the flames, exhaust gas components and two-dimensional unburned flow velocity profiles in a cylindrical chamber. Two types of multi-jet nozzle, parallel- and swirl-type nozzles, were examined in this study. In the parallel-type case, a small change in the distance between the fuel and air nozzles showed significant effects on the blow-off limit. When the air nozzles were closely located around the center of the chamber, the flame was easily extinguished and a pair of elongated flow recirculation was observed near the chamber sidewalls. When the distance was increased, large-scale reverse flows were observed in the central region that led to a stable and efficient combustion. In the swirl-type case, swirl flows made the flame more stable. Some cases of excessive swirl, however, deteriorate the fuel-and-air mixing performance and increase the CO concentration.

Keywords

• confined jet
• multiple jet
• jet mixing
• jet flame
• piv
• gas analysis