Particle Dynamics of Inlet Flowfields with Swirling Vanes

Abstract

The particle trajectories are investigated for the inlet flowfield of a helicopter engine with swirling vanes and particle separator. The flowfield resulting from the swirling vanes is first computed on a hub-shroud midchannel stream surface. The trajectories of the solid particles are then determined in this flowfield, including particle impacts with the hub, tip, and vane surfaces. The particle rebounding velocity and direction after each impact is determined using empirical correlations derived from experiments conducted in a special tunnel. Different particle sizes are considered, and the resulting trajectories and separator effectiveness are presented. and Nomenclature B = tangential space between blades C p -specific heat at constant pressure F = vector normal to midchannel stream surface proportional to tangential pressure gradient H = stagnation enthalpy TV = unit vector normal to the vane, hub, or tip p = stagnation pressure R = gas constant r = radial distance from the axis r c = radius of curvature of meridional streamline 5 = entropy s = distance along orthogonal mesh lines in through-flow direction T = temperature t = distance along orthogonal mesh lines in direction across flow T = unit vector tangent to the vane, hub, or tip u = normalized stream function V = flow velocity V p -particle velocity z = axial coordinate ot = angle between meridional streamline and axial direction /3 = angle between flow velocity vector and meridional plane j8 7 = angle between impacting particle velocity and the surface 6 = angular coordinate p = gas density p p = particle density r =time </ > = angle between s line and axial direction Subscripts i = inlet conditions m = component in direction of meridional streamline TV = component normal to vane, hub, or tip surface n -f»a rti r«1p» r s t T Z = particle = component in radial direction = component in s direction = component in t direction = component tangent to vane, hub, or tip surface = component in axial direction = component in tangential direction Presented as Paper 81-0001 at

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