Experimental Investigation on Flow Characteristics of a Reverse-Flow Combustor

Abstract

Reverse-flow combustor is widely used for small engines to overcome high speed shaft whirling problem and to provide a low frontal area. An experimental investigation was carried out to research the flow field characteristics of a reverse-flow combustor in this paper. Different aerodynamic conditions were studied using PIV to reveal the characteristics of both the nonreacting and reacting flow fields. The structure of the nonreacting flow field in the central section shows similarity as the total pressure loss coefficient increases. The penetrating depth, jet angle, recirculation zone position, and the flow streamlines are similar, while the velocity value of the flow field increases. The structure of the reacting flow field on the central section is different from that of nonreacting flow field, but the variation trend of the reacting flow field under different pressure loss coefficient is similar to that of the nonreacting flow field. By examining the nonreacting and reacting flow fields under the same total pressure loss conditions, marked differences were observed in the primary zone close to the swirler outlet. The relative motion between fuel injection, airflow, and combustion affects the flow field in this zone. The velocity with combustion is faster than that of the nonreacting flow because of the increased temperature and heat release.