Propulsive fuselage concept- A smarter way to increase efficiency
Propulsive fuselage concept is a new technique in the aircraft propulsion technology to increase the propulsive thrust and reduction of skin friction drag. This approach helps to distribute the generation of thrust along the viscous wake generated by the fuselage and reducing the effective drag of the aircraft and hence increasing propulsive efficiency.
The propulsion system a method intended to ingest the boundary layer so that the de-accelerated airflow near the fuselage can be re-energized. Here, the fuselage fan sucks the air inside from aircraft skin and reduces the significant percentage of fuselage viscous drag. And because of reduced drag the thrust demand will be less and propulsive efficiency will be increased.
How It Work:
Fuselage Propulsion system is a specially designed engine placed at the rear end of the aircraft. It consists of fuselage fan, planetary gear system and Gas turbine engine. At the end of tapered fuselage the fuselage fan is placed. As the aircraft moves forward, small percentage of air is ingested by the fan which enters the S-duct whose other end is connected to the engine inlet. The S-duct guides the air into the engine mounted at the tail region of the fuselage. There ,the air is compressed ,mixed with fuel, ignited in combustion chamber and expanded in the turbine, which rotates the drive shaft. Hence fuselage fan rotates at its optimum speed maintained by planetary gear system, thus helps in boundary layer ingestion and drag reduction.
The system is propped with two major functions. First, like other propulsive system it also generates the thrust for the aircraft, although it may not be applicable for heavier aircraft but can be used as secondary propulsive engine.
And the second, as the fuselage fan sucks the airflow from boundary it fills the velocity gap and eliminates the skin friction drag.
The combination of propulsion system and aircraft structure to form a “Propulsive Fuselage” which effectively ingests the boundary layer ,is considered a promising pathway towards a significant increase in overall efficiency of future aircraft. Moreover this concept could also enable fuel savings effectively through much improvement in near future.
Article: Pawan Subedi
Department of Mechanical Engineering, IOE, Pulchowk Campus