Flow Behavior With an Oscillating Motion of the Impinging Jet in a Dump Diffuser Combustor

The paper presents the flow behavior with an oscillating motion of an impinging jet upon a flame dome head and its reattachment to the casing wall, when a distorted flow is provided at the inlet of the dump diffuser combustor. Laser Doppler Velocimeter was used for the measurements of the time-averaged flow within a sudden expansion region. Surface pressure fluctuation survey on the flame dome head and flow visualization by a smoke wire technique with a high-speed video camera were conducted from the view point of the unsteady flow feature of the impinging jet. There exists the high vorticity region at the jet boundary resulting in the production of the turbulence kinetic energy. In particular, higher vorticity is observed in the higher velocity side of the jet. The jet near the dome head has the favorable characteristics about the flow rate distribution into the branched channel. Reynolds shear stress and turbulence energy are remarkably produced near the reattachment region. The jet has an oscillating motion near the dome head with asymmetric vortex formation at the jet boundary.