Экологичность авиастроительной промышленности

Аннотация

Цель данной работы - ознакомиться с последними экологическими инновациями в авиастроении. Основная причина создания новых типов самолетов - экологические проблемы. В статье показаны новейшие концепции летательных аппаратов, которые не наносят вред окружающей среде.

Полный текст

1 Introduction

Nowadays people pay a lot of attention to ecology. This is the key point in designing new aircrafts. During 1990s air pollution associated with aviation and airport-related sources became a prominent issue facing many of the large air carrier and general aviation airports in the United States. Today, criteria pollutants [carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3) and its precursors—oxides of nitrogen (NOx) and volatile organic compounds (VOCs)—sulfur oxides (SOx), and particulate matter (PM)] from airports account for less than 0.5% of total emissions in the United States (2003 General Accounting Office Report to Congress). Nevertheless, aviation sources, like those associated with other transport modes, can contribute to local air quality issues. For example, activity at a single large airport or at multiple airports in an area typically contributes up to five percentage points to an area’s NOx inventory. Such effects may present especially difficult problems for future aviation capacity growth as 41 of the 50 busiest airports in the United States are located in ozone nonattainment and maintenance areas. [1]  However, according to a recent survey aviation kerosene is used as the main fuel which is ecologically destructive.  Aviation currently accounts for 2.5% of global carbon dioxide emissions, but this share is expected to grow as the number of passengers could double in the next 20 years.  For this reason, the problem of alternative energy sources is becoming more urgent. This work is based on survey, the result of it is shown on diagram. (1)

Diagram 1: The most perspective type of fuel

2 Alternative energy sources

There are quite a lot of different energy sources. The list includes: electricity, nuclear and hydrogen liquid fuel. All these types will be discussed and the prototypes also shown.

2.1 Nuclear energy sources

It is common for people to hear the words ‘nuclear power’ and think that it is dangerous, but in the case of nuclear fusion it’s not true. Fusion – the fusing of two or more atoms into a larger one – creates more energy but does not create polluting waste products. At the same time, it’s ‘green’ without creating dangerous waste.

The idea of using nuclear energy is not new. One of the first prototypes was done in the USSR, it was called Tu-119. The reactor was equipped with hydraulic lifters for ease of maintenance. The first launch of the ground-based stand reactor was made at the Semipalatinsk test site in 1959. The aircraft was refitted by 1961 and 34 flights were performed from May to August. Flights were performed with both hot and cold reactors. Basically, the biological protection of the cockpit was checked. Based on the test results, it was decided to continue work on this topic. The work began on the design of an experimental machine "119".

The crew and experimenters were located in the front pressurized cabin, where a radiation detector was installed. The cockpit was protected by a lead screen. The second sensor was installed in the area of ​​the cargo compartment, where the combat load was located. The third sensor was located in the rear cockpit. In the middle part of the fuselage there was a compartment with a reactor with a powerful protective shell.

At about the same time, research on aircraft with nuclear power plants was also carried out in the United States. As in the USSR, flights were carried out with working reactors on board. But, at approximately the same time, in the early 1960s, all work on the nuclear power plant of atmospheric aircraft was discontinued. One of the possible reasons for the termination of work is the fact that in the event of a plane crash, the consequences of the fall of an aircraft with a nuclear reactor on board would be catastrophic.

Some of designers still try to create nuclear aircraft. The Flash Falcon looks like a spacecraft from the video game. It would carry 250 passengers at Mach 3, in an airframe more than 130ft (39 metres) longer than a Concorde and with a wingspan twice as wide. Its engines would even be able to tilt up to 20 degrees to help the aircraft take-off and land like a helicopter. At the heart of the Flash Falcon is something even more revolutionary; the aircraft is designed to fly on nuclear power, with a fusion reactor pumping energy to its six electric engines. No prototypes have been built though – the design so far lives only in the imagination of Spanish designer Oscar Vinals.

The idea of nuclear plane is rather prospective, but more research is required to make it safer for pilots and in case of crash.

2.2 Liquid hydrogen aircraft

Another promising type of fuel is liquid hydrogen. This fuel is more learned, we are using it in cars and also start to use in airplanes. Airbus unveiled three hydrogen-fueled zero-carbon aircraft concepts. Cryogenic fuels are environmentally cleaner than gasoline or fossil fuels. Among other things, the greenhouse gas rate could potentially be reduced by 11–20% using LNG as opposed to gasoline when transporting goods. We will discuss each project carefully.

Table 1: Characteristics of ZEROe projects

The first concept is a turbofan-powered aircraft that can carry up to 200 passengers and can fly over 3,700 km at a time.  This aircraft uses modified gas turbine engines that run on hydrogen instead of kerosene.

The second concept is a turboprop aircraft that can accommodate about 100 passengers for short-haul flights (up to 1,850 km).  The aircraft also runs on liquid hydrogen.

The company also unveiled a third concept using a V-shaped flying wing design, which will carry up to 200 passengers and fly over 3,700 kilometers.

Over the next five years, Airbus engineers plan to develop hydrogen technologies.  In a few months, the company will begin testing hydrogen fuel cells and hydrogen combustion technologies.  By 2025, Airbus expects to launch the ZEROe aircraft building program, with a full-fledged prototype aircraft to appear by the end of the 2020s. Short information you can find in Table 1. [2]

2.3 Electricity

The most ecological and free damage is electricity. The main problem is that it hasn’t enough power to get plan in the air. That is why hybrid installation is more promising. During take off the plane needs more power and uses hydrogen fuel or kerosene. After reaching cruising speed first engines stop working and electrical ones begins. This configuration is now widely used in designing new planes. And it is also the most prospective because not only prototypes were done, but real planes.

A French aviation startup called VoltAero released the final design of its nine-seat Cassio 2, a hybrid aircraft with a cruising speed of 230 mph—much faster than conventional single-prop planes—that will be able to fly in electric-only mode for 125 miles. We suppose the futuristic-looking Cassio 2 could enter the market within two years.

The Cassio 2 is a breakthrough in electric-aircraft design because it combines leading-edge aerodynamics and electric-hybrid propulsion to make it much quieter, more efficient, and greener than conventional plane.

In 2010, Airbus embarked on its electrification journey, developing the world’s first all-electric, four-engine aerobatic aircraft, CriCri. Since then, they have made significant progress in the electrification of flight. Their all-electric, twin-propeller aircraft E-Fan successfully crossed the English Channel in 2015. Electric vertical take-off and landing projects, Vahana and CityAirbus, have completed many hours of flight testing programmes to ensure safety and high performance. E-Fan X, the successor to E-Fan that is 30-times more powerful than its predecessor, has provided invaluable insights on serial hybrid-electric propulsion.

3 Conclusion

To conclude we would like to say that aircraft industry is developing. And back in early 2000 the developments mentioned in the work would seem absolutely fantastic. And now they are part of our future life. According to the information in this article it is possible to say that every innovation has its strong and weak points. That is why we are sure we will not use only one source of energy in future. Therefore, hybrid fuels will be a better choice.