Design Guidelines for Inertial Particle Separators

Abstract

Inertial particle separators (IPS) are air-cleaning devices integrated with air intakes or engine inlets to remove potentially harmful particles through the action of centrifuging. Their geometry is defined by a mean gas path, which sits at the centroid of a duct cross section. Advances in additive manufacturing are opening up new opportunities to explore a wider design space and optimize for more mission-specific requirements. The current work presents design guidelines for these devices and explores the effect of certain geometric parameters on the competing objectives of maximum separation efficiency with minimum pressure loss, through a reduced-order model. The model framework computes the centripetal drag force by first transforming the principal mean gas path into the Frenet–Serret reference frame to measure the local radius of curvature, and second, solving the local one-dimensional flow field by application of the isentropic flow equations for ideal gas. The loss in pressure due to wall friction, bends, and rapid area expansion are accounted for at each point along the gas path. The capability of this approach is demonstrated through comparison with a known test case in the literature, followed by application to a hypothetical conceptual design. Primary design parameters of splitter position, throat position, gas path curvature (through spline control points), and scavenge mass flow are chosen for investigation. Key findings are that the IPS cross-sectional area and hump curvature could be used together as effective tuning parameters, to maximize the separation efficiency for a given target test dust.