The Influence of Development and Fan/Screen Interaction on Screen-Generated Total Pressure Distortion Profiles

The rising interest in fan performance in the presence of total pressure distortion, a topic of fundamental interest for integrated airframe/engine architectures, has led to increased research in ground based testing environments. Included in these studies is the generation of simulated total pressure distortion profiles using wire mesh screens. Although the inlet duct development of total pressure distortion patterns has been studied in a historical context when distortion effects on engine performance were first of interest, these were typically simplified experimental studies for low-speed flows. To aid in the understanding of total pressure distortion development approaching a transonic fan face, a series of experiments were conducted to detail the development of such a profile downstream of the screen plane in the absence and presence of fan effects.

Presented is an extensive experimental set to detail (1) the evolution of a screen-generated total pressure distortion profile as it develops in a constant diameter inlet duct and (2) the effect that a single stage transonic fan has on the distortion development. Included is a detailed analysis of the distortion profile characteristics for increasing development length, and the behavioral changes of the profile when fan blockage is present near the screen plane. Recommendations are made regarding the placement of total pressure distortion screens relative to the fan face, and insights are given into the expected profile evolution. This work is a contributing part of an ongoing systematic investigation of fan performance when subjected to screen-generated total pressure inlet distortion.