DEVELOPMENT OF SILENT AIRFRAME CONCEPTS AND INNOVATIVE CYCLE PROPULSION SYSTEMS FOR REDUCTION IN AIRCRAFT NOISE

摘要

This paper will describe a range of innovative airframe configurations and several novel gas turbine cycles; aiming to produce a combination of gas turbine and unconventional airframe technologies, resulting in a low noise viable civil airliner. The combined Airframe and Propulsion technology study is a collaboration of Cranfield University alongside the joint venture of the Cambridge-MIT Silent Aircraft Initiative'. Numerous tools have been used in investigating the low noise aircraft design, emphasizing on performance. Airframe design includes semi-empirical design methods (D. Howe and Loftin performance) with engine design incorporating the TURBOMATCH performance code. The noise analysis focuses on airframe and engine noise, using semi-empirical ESDU codes. Airframe configurations were down-selected to seven main concepts, each requiring further development to determine an optimum concept for a low noise viable future airliner; requiring high fidelity noise prediction. Noise is critical to engine design, whereby increasing bypass ratio results in reduced jet noise, but increases fan noise unless there is a radical fan redesign. The airframe-engine integration is of utmost importance for performance and noise shielding.