An experimental investigation of confined, multiple, turbulent jet mixing with recirculation

An axisymmetric duct that simulated a combustor configuration, was used to examine the flow fields in combustors that utilize injector plates to establish turbulent jet mixing of fuels and oxidizers. Five different injector plates were tested. Flow fields downstream of the plates were investigated using flow visualization and laser velocimetry. Qualitative data for flows created by rings of discrete jets were obtained with dye injection and hydrogen bubble generation flow visualization techniques. Wall static pressure distributions were measured with a sensitive pressure transducer. The velocity and turbulence fields were quantified using a Bragg-diffracted, two-component laser doppler velocimeter (LV). The locations and extents of recirculation zones and jet expansion rates were deduced from the LV data. Results show that the flow due to an annular jet is two dimensional, but those due to discrete jets are fully three dimensional.