CONICAL DIFFUSERS WITH INFLOW DISTORTION ESTIMATED PEAK LOCAL VELOCITY AT EXIT

摘要

A simple analytical expression relating exit and entry distortion factor, VMAX/VMEAN, for a conical-type diffuser is derived. The expression involves two assigned constants, values for which are obtained from a quantitative fit of measured data for a series of six conical diffuser configurations, operated with cross-flow generated inflow distortion at entry distortion factors up to about 3.0. Corresponding expressions for momen¬tum coefficient and static pressure recovery coefficient are presented and shown to reproduce observed trends. The corre¬lation is used to indicate a lower bound to the peak local velocity at exit from a practical gas turbine exhaust system consisting of an unassisted diffusing elbow followed by a straight conical-type diffuser.