Table of Contents
Introduction
This research paper presents a general overview of modern trends in the aircraft fuel systems, such as the use of geared turbofan engine, composite ceramics, and biofuel. Short explanations of innovations give an understanding of their necessity and provided benefits. Also, examples of implementation and successful use of these modernizations into real life are described below. The innovations will increase effectiveness and efficiency of work of fuel system and provide an ability to use higher temperature to receive more energy from less fuel. These trends are extremely important for the whole aircraft industry because they bring such benefits as lower fuel consumption and operational expenses; increasing aerodynamics; lowering noise and even the greenhouse effect. Described modern trends of the aircraft fuel systems will make aircraft faster, cheaper, safer and less harmful to the environment.
New Developments in the Aircraft Fuel System
Different articles were used for this research paper. Most of them are internet articles that highlight the most prominent events of the aircraft industry all over the world. Also, a combination of information from different articles provides an independent and unprejudiced vision of the modern trends of the aircraft fuel systems. This research paper covers the following innovations in the aircraft fuel systems: geared turbofan engine, composite ceramics, and the use of biofuel.
Geared Turbofan Engine
Pratt & Whitney Company had introduced and implemented one of the methods of increasing efficiency of turbofan engine by incorporation a special gear into an aircraft fuel system. Fan-drive gear system consists of a gearbox that weighs 113 kg and is 45 centimeters long and ‘has 30,000 horsepower passing through it’ (Grose, 2013). This engine expels hot gases from the core. Gasses have sufficient speed and can create thrust. These fans ‘push slower air around the outside of the engine, so it mingles with the faster hot gases at the rear, increasing thrust’ (Grose, 2013). Such technology provides an increase of bypass ratio of engine from 8:1 to 12:1. That means that twelve pounds of air hitting the engine bypass the core for every pound that enters. Moreover, the implementation of a gearbox into an aircraft fuel system allows the two to spin irrespectively. So, new technology implemented in geared turbofan engines leads to decreasing the number and weight of turbines and an increase in fans.
The first testing of a geared turbofan engine (model PW100G) was performed on an Airbus A340-600 in 2008. The examination of an improved model PW1100G was performed in 2013 on the 747SP (Croft, 2011). Pratt & Whitney started the manufacture of geared turbo engines after conduction some examinations that approved the safety and efficiency of this innovation.
Such giant air companies as Airbus (Airbus A320neo), Embraer (Embraer E-Jets E2) and Bombardier (Bombardier C Series), Mitsubishi (Mitsubishi Regional Jet), Rekkof Aircraft (the Fokker 120) have placed more than 3000 orders on the new geared turbofan engine for the nearest several years. This innovation was already implemented in the design of Boeing X-48C Hybrid Wing Body aircraft (Grose, 2013). The geared turbo engine is used in a family of airplanes the Airbus A320neo. The Federal Aviation Administration (the FAA) approved and certified this innovation of the aircraft fuel system of Airbus A320neo on December 19, 2014 (“FAA certifies,” 2014). These new airplanes have such benefits connected with implementation of the geared turbo engine as decreased noise production (by about 75 per cent), lower operational cost, and decreased consumption of fuel: ‘GTF architecture allows room for growth as demonstrated by the additional 2 percent fuel burn enhancement, which will further reinforce the A320neo's 20 percent fuel burn savings per seat by 2020’ (“FAA certifies,” 2014). Rekkof Aircraft in cooperation with Pratt & Whitney’s improved their new Fokker 120 by an installation of the geared turbofan engine in ‘tail-mounted engine position’ (Netherlands Aircraft Company, n.d.). The geared turbofan engine will be used in Embraer E-Jets E2. Manufacture of these planes is scheduled on 2018 (Polek, 2013).
The modernization of turbofan engines decreases average consumption of fuel on about 16 per cent (Grose, 2013). Also these innovations will lead to the reduction of operation expenses of Pratt & Whitney Company by about 20 per cent. Moreover, a combination of use of gear and lightweight materials provides such benefits as improvement of aerodynamics, decrease in carbon dioxide emissions into the atmosphere by more than 3,000 metric tons annually, and reduction of the level of noise by about 50 per cent.
Composite Ceramics
Composite ceramics is one more modern trend used in the aircraft fuel systems. The main benefit of the use of composite ceramics in the aircraft fuel systems is increased combustion temperature. Engine parts like turbine blades from composite ceramics can ‘withstand temperatures approaching 1,300°C to 1,500°C (2,372°F to 2,732°F)’ (Grose, 2013). Scientists decided to mix several ceramic fibers in order to decrease such negative characteristic of ceramics as frailty and to increase ductility. Also, this innovation provides such benefits as decreasing fuel consumption, reduction of weight of parts of the engine and decreasing noise.
Innovative engine nozzle made from composite ceramics was tested by Boeing array in Moses Lake, Wash in 2014 (“Not your mother's ceramics,” 2014). Additional testing flights of ecoDemonstator 787 Flight Test Airplane are planned for 2015 in order to investigate and approve the use of composite ceramics in the aircraft fuel systems.
Biofuel
Nowadays some aircraft use biofuels, which are retrieved from different organic sources, biomass and waste products. The examples of organic sources are algae and plants (Sustainable Aviation Fuel Users Group, n.d.). The examples of waste products are solid waste, by-products of different industries and waste cooking oil (Sustainable Aviation Fuel Users Group, n.d.).
Biofuels can be produced from energy-rich organic substances in different continents of the world. Project Solaris is another notable program developed by Sunchem SA, Boeing and SkyNRG and the SAA. This program is directed towards the development and implementation of the full supply chain for production of biofuel from so-called Solaris. Solaris is a tobacco plant that does not hold nicotine. Project Solaris comprises more than 120 acres of Solaris on both private and community farms. It is expected that biofuel produced in terms of Solaris Project can be used for the needs of Boeing and the South African Airlines in 2016 (Lane, 2015). However, not only tobacco plants can be used for making biofuel. The Red Rock Biofuels (the RRB) Company develops and implements the technology of making biofuel from forest residues. In September 2014 the RRB signed a contract with Southwest Airlines. According to this contract, more than 3 million gallons of biofuel will be supplied for flights at Southwest’s Bay Area in 2016 (Lane, 2015). Green fuel technologies can also be produced from the feedstock. Petrixo Oil & Gas, UOP Renewable Jet Companies intended to build a special refinery factory in the UAE (Fujairah) this year (Lane, 2015). It is expected that the factory will produce about 500 thousand of biofuel annually. Also, contracts for the investigation and production of biofuel were signed between such companies as Boeing and Embraer for the creation of a joint research center in Brazil; Airbus and Emerging Fuels for the production and supply of biofuels; Boeing, Hangzhou Energy & Engineering Technology Co., and Commercial Aircraft Corp for the production of biofuel from waste cooking oils in China; the Byogy Renewables and AusAgave Australia for the production of biofuel from food stock (Lane, 2015).
The use of biofuel allows decreasing carbon footprint and carbon emission. In distinct from biodiesel, which can be oxidized during long-term storage at low temperatures, biofuels do not incorporate any substances based on paraffin. So, hoses and seals of aircraft fuel system are not inclined to shrink. Aircraft that use biofuels do not emit SO2 (sulphur dioxide) because there are no sulphur components in biofuels. So, the use of these fuels can lead to a considerable reduction of the greenhouse effect (by about 75 per cent) (“Airlines win approval,” 2011).
Virgin Atlantic Company was the first company which performed tests of aircraft using biofuels. In 2008 the Boeing 747 made a flight between the capital of the UK and the capital of the Netherlands (Virgin Atlantic, n.d.). It should be mentioned that this test was performed with using a composition that consists only of 20 per cent of biofuel. The first test of aircraft that uses biofuel in Asia was performed by Air China Company only in 2011 (Mei, 2015). This company tested the same model of Boeing (Mei, 2015). It should be mentioned that Boeing closely cooperates with numerous Asian companies in performing biofuel tests (Chinese Academy of Science, Commercial Aviation Corporation and other research institutions) (Mei, 2015).
Further, the chemical content of fuel was changed. Nowadays, it usually consists of 50 per cent of biofuel and 50 per cent of common petroleum. This provides further lowering of harmful emissions of carbon dioxide and sulphur into the atmosphere.
At the present time biofuel is used in more than 1,500 commercial flights (Sustainable Aviation Fuel Users Group, n.d.). Such aircraft giants as Boeing, Sinopec and Hainan Airlines performed the first commercial flight by using biofuels from an airport of Shanghai to an airport of Beijing on March 21, 2015 (Mei, 2015). This biofuel was produced by using waste from cooking oil. As it was mentioned above, not pure biofuel was used of this flight. The fuel consisted from petroleum jet fuel (50 per cent) and biofuel (50 per cent). This particular experiment showed in practice that the use of biofuel can lead to the reduction of carbon emission by from 50 per cent to 80 per cent compared to the use of common petroleum jet fuel (Mei, 2015).
Biofuels are widely used for commercial and private flights in Europe. In the previous year a decision to supply airports of Northern Europe with biofuels was supported by such companies as Avinor, SAS, KLM, Statoil Aviation and Lufthansa Group. These companies intend to supply and use more than 2 million liters for flights in the capital of Norway and Bergen. Thus, ‘OSL is the first major airport in the world to offer a regular supply of bio-fuel as a part of daily operations from March 2015’ (Lane, 2015). It should be mentioned that European airlines use a mix of fossil aviation fuel and biofuel in ratio 52 per cent of fossil fuel and 48 per cent of biofuel. Norwegian Air Company performed such flights (with using biofuel) from Trondheim airport to Oslo Airport in November 2014 (Lane, 2015).
Biofuels are successfully used not only for regular flights. Gol Airlines intended to perform ‘over 200 flights on a 4% biofuel blend during the World Cup’ (Lane, 2015). This company has already preformed flights with the use of biofuels between an airport of San Paolo and an airport of Brasilia in 2013.
The idea of using biofuels in the aircraft fuel systems became a reality and a modern trend only four years ago. International contracts for wide production and use of biofuels were signed only in 2014 and 2015. However, as we see nowadays this idea is successfully implemented all over the world (in production of biofuels and in performing commercial flights).
Conclusion
This research paper described the use of geared turbofan engines, composite ceramic components and biofuels in the aircraft fuel systems. These trends are united by one beneficial idea that has the goal to improve the work of the aircraft fuel systems and the whole mechanism by decreasing fuel consumption and lowering operational costs. The use of composite ceramics and geared turbofan engines provides such considerable benefit as lowering the weight of parts of a fuel system and the whole aircraft. This leads to increased aerodynamic. Also, the use of biofuel leads to reduced carbon dioxide emission into the atmosphere and considerable lowering of the greenhouse effect.