Blowing Ratio Effects on an Inclined Jet in Crossflow

The inclined jet in crossflow is a canonical variant on the perpendicular jet in crossflow and is used extensively in gas turbine film cooling applications. Few studies have examined the turbulent scalar transport at blowing ratios (BR) greater than one, where jet lift-off can reduce the film cooling performance. This experimental work studies the effect of blowing ratio on a round jet pitched at 30° from horizontal, a jet Reynolds number nominally of O(5000), and boundary layer thickness to jet diameter ratio of 2. Magnetic Resonance Velocimetry (MRV) is used to obtain the 3D, 3-component mean velocity field on a Cartesian grid of approximately 2 million data points at BR = 1.5 and BR = 2.0. Magnetic Resonance Concentration (MRC) is used to measure the 3D mean concentration field at BR = 2.0. Jet trajectories, counter-rotating vortex pair (CVP) structures, and mean scalar fields are compared to data previously collected with MRV and MRC at BR = 1.0. Attention is given to turbulent mixing on the leeward side of the jet, which can be modulated by proximity to the wall and critically determines film cooling effectiveness. Blowing ratio affects the distortion of the jet streamtube by the CVP, especially on the bottom side of the jet.