Velocity field characteristics of a swirling flow combustor

Abstract

Data for reacting and nonreacting flows obtained by laser anemometry in a swirl combustor are reported and discussed. The combustor consists of two confined, concentric swirling jets. The central jet flow is premixed methane/air; the annular jet flow is air. The two flow conditions investigated are flow rotation in the same direction (coswirl) and in opposite directions (counterswirl). A closed, central recirculation zone is observed in both swirl conditions for reacting flow, but only in counterswirl for nonreacting flow. Large, anisotropic velocity fluctuations are observed in high shear regions and in the vicinity of the recirculation zone. Mechanisms for swirl-generated recirculation zone formation are discussed.