An Experimental Study of the Flow in a Low-Pressure Swirl Chamber

摘要

An experimental study was conducted to determine the nature of the flow in a low-pressure swirl-flow chamber which provided endwall boundary layer control by injection or 'reverse-flow' capabilities as optional. For part of the investigation water flows were used while dye streams were observed in attempts to determine streamline patterns; for the remainder, air flows were examined by means of a special probe from whose measurements the velocity profiles were determined. The chamber flow consisted of three main zones; the core, the main body and the boundary layers. The core, which rotated wheel-like, contained an inner, nearly-stagnant core and an outer sheath which exhausted out the chamber exit. The outer body of fluid moved in a vortex-like manner but contained low-order axial and radial flows which resulted in unexpected cell movements. The boundary layers on the endwalls spiralled inward toward the center, as dictated by the radial pressure gradient, but were effectively reversed by the endwall injection. The mode of injection and the overall pressure ratio were found to have strong effects upon the flow but there was little or no influence from variations in Reynolds number and from a number of minor geometric changes. (Author)