Nacelle Design for Mixed Turbofan Engines

Nacelles are responsible for good engine performance and considerable percentage of total aircraft drag, thus fuel consumption. Energy conservation and cost of fuel, among others, require good nacelle design. CFD calculations of the flow around it are a major design tool to predict shock waves, internal boundary layer in the nacelle forebody, high velocity zones and wake. Commercially available software may be used to calculate and visualize the flow at the most critical parts of the nacelle, allowing design modifications aiming at optimizations. This paper overviews the literature on nacelles, the methodologies involved in the design. A case study is presented for a long duct nacelle design, using an axis-symmetric model. Performance characteristics at important operating conditions are also presented.