Experimental studies of combustor dilution zone aerodynamics. I - Mean flowfields

An experimental investigation has been carried out to study circumferential irregularities in the temperature distribution downstream of a row of 16 heated jets injected normally into a confined annular crossflow at a momentum flux ratio of 4. The heated air was fed to the plunged holes along a representative approach annulus and, despite the uniformity of the approach flow, the velocity profile across the exit plane of each dilution hole revealed a complex flowfield that varied in a random manner from one jet to another. Temperature distributions measured at a plane two hole diameters downstream indicated a lack of symmetry between the dilution jets because of an apparent twist of the temperature contours associated with certain jets. Velocity distributions at the same location indicated a corresponding asymmetry in the double-vortex structure formed in the wake of each jet.