The effect of rotation and buoyancy on flow development in a rotating circular coolant channel with radially inward flow

Abstract The influence of rotation on the development of pressure-driven air flow in a circular-sectioned coolant channel is presented in this article. The channel is rotating about an axis perpendicular to its own centerline with an eccentric orientation, representing a typical configuration in turbine blade cooling design. As a first step, radially inwad directed flow has been examined. The opposite case, radially outward directed flow, is still under investigation and will be presented in the enar future. The flow field of the duct is investigated by means of experiments and numerical calculations that demonstrate rotation effects under both isothermal and heated flow conditions. Coriolis forces generate two counterrotating vortices in the flow and change the distributions of flow velocity as well as turbulence instensity. In the presence of density variations across the channel induced by thermal fluxes, buoyancy forces arise; significantly influencing the turbulence. Turbulent pipe flow with Reynolds numbers up to 60,000 is covered by the experiments, with the rotation number in the 0 to 0.1 range. The buoyancy parameter was chosen to be 0.04. Nonintrusive flow measurements were performed with an advanced Laser-2-Focus velocimeter (L2F). A finite-element flow analysis code is adapted to this flow situation, solving the three-dimensional Reynolds-averaged Navier-Strokes equations. The experimental data help to understand the Coriolis and buoyancy force affected flow phenomena and provide test data for the validation of numerical flow prediction.