View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Chalmers Publication Library 1 ISABE-2005-1122 DISTRIBUTED PROPULSION AND TURBOFAN SCALE EFFECTS Anders Lundbladh Volvo Aero Corporation S-46181 Trollhättan, Sweden
[email protected] Tomas Grönstedt Chalmers University Sweden ABSTRACT ps Propulsion System, i.e. exclusive of airframe drag effect on intake pressure recovery A coupled aircraft and engine model is used to evaluate the fuel consumption and mission weight of distributed propulsion aircraft. The engine cycle is INTRODUCTION optimized for the installation to show the ultimate performance of each propulsion alternative. The A conventional subsonic transport aircraft is effect of higher specific fuel consumption for smaller equipped with two to four turbofan engines. The engines is weighed against the potentially lower trend from the fifties until now has favored the twin installation weight and higher integration efficiency underwing engine configuration. An alternative is to of distributed propulsion. use a large number of engines. This concept can broadly be described as distributed propulsion. Nomenclature More than four engines have been used in the past for reasons of reliability and unavailability of V Velocity relative to the aircraft sufficiently large engines (compare e.g. the “Spruce T Total propulsive thrust Goose” and the B-52). Reliability concerns also led P Propulsive power to the requirement that an ocean crossing aircraft D Drag must have at least three engines, although the number FHV Fuel Heating Value of routes affected by this has decreased due to W Mass flow ETOPS qualification of twin engine aircraft.