The aircraft industry has always been fast and very advanced in multiple aspects of engineering field. Aircraft propulsion is a fast-moving field of research and development. Today we are striving towards the Ultra Efficient Engine Technology (UEET) that has 3 main challenges: have an engine accommodating all kinds of speeds; increase efficiency and reduce emissions; reduction in NOx emissions. To meet these goals, 7 technology areas are being looked into under the UEET program.
Most, if not all, commercial aircrafts today are using the turbofan and this is not mere coincidence. From the humble beginnings of propulsion where piston engines were employed, propulsion has seen a wide variety of engines. This report will be looking into a timeline involving the various engine types and why these engines became history soon after they surfaced, leaving the jet engine to dominate to propulsion field. Even while the jet engine emerged the obvious choice, there were numerous modifications made to the jet engine. This report will weigh the benefits of the different variations: turbojet, turbofan, turboprop and ramjet. Each of these engines excels in their own range of flight conditions but for the commercial aircraft, turbofans were the most suitable and practical.
While turbofans remain the choice of today, research carries on under the UEET program and there are several design drivers that are being looked into. Market demand is always high, strict and asking for prices as low as possible. These are always compromised by regulatory standards and technical limitations. Regulatory standards revolve around aircraft noise and pollutant emissions. These factors are actually being looked into in the development of UEET. Technical limitations include material limitations and structural limitations. Every material can only handle a certain range of conditions and will fail no matter how strong it is. Despite this, new materials are constantly being produced with composite materials and superalloys being the current favourites.
From where the forefathers of aircraft propulsion left us, we have certainly made leaps and bounds of improvements to the engine. The UEET program by NASA is the latest step towards perfection of the engine. This program is worldwide and involves numerous big names in the aviation industry. The continuous search for materials and methods to withstand harsher conditions is going strong.
