Computational Study of the Embedded Engine Static Pressure Thrust Propulsion System

Drag reduction is being pursued for next generation aircraft to reduce fuel consumption and pollutant production. Drag reduction of fuselages is now receiving more consideration, since the fuselage represents 30% of the drag of the entire aircraft. This paper presents numerical simulations of earlier experimental studies using aft suction slots and embedded propulsor systems to reduce fuselage drag. Detailed grid refinement studies were conducted, and different turbulence models were evaluated. A simulation of an airship with a boundary layer suction slot and an embedded engine with aft injection of the ingested flow for propulsion was conducted. The simulations require significantly more propulsor power to achieve a self-propelled condition than reported in the experiments, which were subject to large experimental uncertainties. The computational fluid dynamics flow field can be interrogated in detail, leading to improved understanding of the performance and integration of all system components. The particular arrangement studied in the experiments was shown to be limited by significant internal flow losses. This study provides the basis for the much improved integration of an embedded engine and gives the starting point for a wider analysis of more slender bodies operating in a transonic flow field for application to modern transport aircraft.