An assessment of distributed propulsion: Advanced propulsion system architectures for conventional aircraft configurations

Abstract

Radical aircraft and propulsion system architecture changes may be required to continue historic performance improvement rates as current civil aircraft and engine technologies mature. Significant fuel-burn savings are predicted to be achieved through distributed propulsion, where an array of propulsors is distributed along the span of an aircraft to ingest boundary layer air and increase propulsive efficiency. The paper is divided in to two parts of which this is Part A, which presents the conceptual design tool, which has been developed to model the selected aircraft. It is followed by an evaluation of distributed propulsion on tube-and-wing aircraft configurations. The distributed propulsion aircraft has been compared with both a current technology reference aircraft and an advanced turbofan powered aircraft of 2035 technology. The latter achieved a 27.5% fuel-burn reduction relative to the baseline aircraft and the distributed propulsion variant showed further fuel efficiency gains of 4.1% due to the reduction in power required by the distributed propulsors, relative to a turbofan in free-stream conditions. Part B assesses the potential for distributed propulsion on a Blended Wing Body (BWB) aircraft configuration and compares the performance with an advanced turbofan variant BWB of the same technology level. The distributed propulsion variant BWB provided a further 5.3% fuel-burn reduction relative to the turbofan BWB through reduced core engine size and reduced specific fuel consumption.