The effect of intake length on aerodynamic characteristics under inlet distortion

This paper described experimental results on the ingested flow to a model fan. The noise, static and total pressures were measured when intake ducts were placed applied in front of the fan. Recent trend of increasing the bypass ratio of turbofan engines requires shorter intake nacelle for reducing weight and the fuel consumption. However, the shorter intake nacelle may increase inlet distortion, which impairs the deteriorating fan aerodynamic performance. The final goal against this problem is to propose a low-distortion intake geometry or to better understand the impact of the ingested flow on the fan performance and noise. The first step of whole this study is to establish the experimental approach. As a result, the long intake duct had a large pressure loss, and the sound pressure level of the long intake duct set equal to the short one regardless of the existence of high inlet distortion. Detailed discussions on the static and total pressure data are described in the final paper. In addition, the experimental results were compared with CFD results under a flow-through condition. With these discussions, the experimental approach will be evaluated for measuring the inlet distortion of the intake duct.