Supersonic Transport

Supersonic Transport

Figure 1 Turbojet Engine
Figure 1 Turbojet Engine
Air transport is a very frequent choice of travel. However, transatlantic flights take several hours to reach its destination. For example, a flight from New York to Paris takes about 10 hours. This loss of time can be very important to many people; for example, the world of business depends a lot on travel and time.This means that business is an international relationship and for this to be done a form of communication must be employed, in this case one of them is travel; travel is used whether to transport people (e.g. businessmen) or cargo (e.g. imports/exports). Therefore, time is crucial in the business market and this can be reduced by employment a much more effective and faster route or medium. Hence, thesuggestion of use of supersonic speeds on airplanes is a reasonable option, rather than the present use of transonic speeds.

Supersonic speeds are considered speeds greater than the speed of sound (343ms-1 in dry air). Supersonic speeds fall into the third place of the Mach regimes scale (fig. 2); supersonic speeds are greater than Mach 1.2 (x > 410m/s) and less than Mach 5 (x <1710m/s).(6) To achieve these speeds, a plane’s engine must be designed to produce enough thrust forces and overcome the high drag transonic flight regime (fig 2 & 3). For a plane to achieve supersonic speeds, turbojets engines are often employed, like the Concorde did.(3) The concept of a jet engine to generate thrust depends on “the velocity of the exhaust gas and the mass of that gas.”(1) Thismeans that an engine can either accelerate the velocity of the gas or increase the mass at which it is exhausted; in this case the gases are accelerated to higher velocities (supersonic velocities). This is achieved through this process (fig. 1): at the intake, air is driven to the compressor, which compresses the air to increase the pressure and its temperature.(13) Then, this air is passed into thecombustion chambers where the fuel is mixed with the air, at this point the air and fuel combust, which dramatically increases the temperature of the gas. The hot air leaves the combustion chamber and goes to the turbine. The turbine starts spinning due to the impact of the hot air; as the air makes the turbine spin, the turbine accelerates the gas and gains energy on the process.(13) Finally,the gas is liberated to the nozzle, which lets the gas expand to atmospheric pressures producing a huge exhaust plume that makes the speed of the gas go supersonic.(13) This produces enormous rearwards forces (fig. 1), which according to Newton’s third law of motion, this creates an equal opposite force. This is known as the thrust force.(5) Therefore, a great force is created, which is sufficientto accelerate the plane to supersonic speeds. Another point to mention is that afterburners are often employed during takeoff to go supersonic due to the high inefficiency of jet engines at low speeds.(3) Afterburners are an addition of thrust, which comes from the direct injection of fuel into the nozzle; because not all of the air is combusted while it is in the combustion chamber, this allows tothe remains to be reignited. Therefore, this provokes for the pressure to rise increasing the amount of thrust produced.(1) A turbojet is the reason why enough force can be achieved to create a supersonic impulse and overcome the subsonic and Figure 2 Mach Regimes
Figure 2 Mach Regimes
transonic regimes (fig 2).
The main reason for using supersonic transport is that it is time travelefficient. This means that travel time is extremely reduced. This was the main marketing selling point for the Concorde and Tupolev Tu-144. This is very convenient for many people that often want to move around continents faster. For example, a flight in a Boeing 747 that travels at a velocity of Mach 0.84 from New York City to Paris would take about 10 hours, whereas in a Concorde, cruising at Mach 2,...