Introduction
In todays society almost everyone has flew on an airplane. Airplane is made up thousands and millions of wires connect multiple components to work together to left the heavy weight manmade bird into the sky. Compare to a human some say the heart or the brain is the most vital organ to keep a human alive but to and airplane without a doubt the engine is the most vital component to keep an airplane safely up in the sky.
History
Sir Isaac Newton is a well respected in the world for his discoveries and contribution the science field. Newton was the first to theorize the rearward-channeled explosion could propel a machine forward at a great rate of speed. This theory was based on his third law of motion. As the hot air blasts backwards through the nozzle the plane moves forward [1].
As most of us are taught that the Wright Brothers were the first to flight but that wasn’t the case. The Wright Brother was the first to successfully fly on a 12 horse power gas powered engine, The Flyer. Henri Giffard built an airship that was powered by the first aircraft engine, a three-horse power steam engine. It was very heavy, too heavy to fly [1]. In 1874, Felix de Temple, built a monoplane that flew just a short hop down a hill with the help of a coal fired steam engine [1]. Otto Daimler invented the first gasoline engine in the late 1800’s [1]. In 1894, American Hiram Maxim tried to power his triple biplane with two coal-fired steam engines. It only flew for a few seconds [1]. Frank Whittle, a British pilot, was the first to design and patented the first turbo jet engine in 1930. The Whittle engine first flew successfully in May 1941. This engine featured a multistage compressor, and a combustion chamber, a single stage turbine and a nozzle [1]. And at the same time Hans von Ohain was working on a similar design in Germany. The first airplane to successfully use a gas turbine engine was the German Heinkel He 178, in August 1939. It was the world’s first turbojet powered flight [1]. General Electric built the first American jet engine for the US Army Air Force jet plane. It was the XP-59A experimental aircraft that first flew in October 1942 [1].
Figure 1: Gas turbine engine designed by Frank Whittle: in 1937 and formally patented two years later. Drawing taken from US Patent: 2,168,726: Propulsion of aircraft and gas turbines, courtesy of US Patent and Trademark Office, with colors and numbers added for clarity. The patent document explains how this engine works in a lot more detail.
Process and Parts
The fundamental idea of a plane engine is a machine that turns fuel into thrust to create a forward motion that is the result of an action and reaction. Thus Newton’s Third law of motion commonly summarizes this motion [7]. This motion is also know was the thrust which is the forward force that pushes the engine resulting of the airplane moving forward
Figure 2: Sir Isaac Newton Third Law of Motion: For every action, there is an equal and opposite reaction.
1. Basic Parts of an Engine
The fan is the first component in a turbofan. The large spinning fan sucks in large quantities of air. Most blades of the fan are made of titanium. It then speeds this air up and splits it into two parts. One part continues through the center of the engine, the second part passes the core of the engine. It goes through a duct that surrounds the core to the back of the engine where it produces much of the force that propels the airplane forward. This cooler air helps to quiet the engine as well as adding thrust to the engine. Then compressor is the first component in the engine core which is made up of fans with many blades and attached to a shaft. The compressor squeezes the air that enters it into progressively smaller areas, resulting in an increase in the air pressure. This results in an increase in the energy potential of the air. The squashed air is forced into the combustion chamber. Next in the combustor the air is mixed with fuel and then ignited. The mixture of air and fuel catches fire. This provides a high temperature, high-energy airflow. The fuel burns with the oxygen in the compressed air, producing hot expanding gases[4]. The inside of the combustor is often made of ceramic materials to provide a heat-resistant chamber. Following the high-energy airflow coming out of the combustor goes into the turbine, causing the turbine blades to rotate. A shaft to turn the blades in the compressor and to spin the intake fan at the front links the turbines. This rotation takes some energy from the high-energy flow that is used to drive the fan and the compressor. The gases produced in the combustion chamber move through the turbine and spin its blades. The turbines of the jet spin around thousands of times. They are fixed on shafts, which have several sets of ball bearing in between them. Lastly the nozzle is the exhaust duct of the engine [5]. This is the engine part that actually produces the thrust for the plane. The energy depleted airflow that passed the turbine, in addition to the colder air that bypassed the engine core, produces a force when exiting the nozzle that acts to propel the engine, and therefore the airplane, forward. The combination of the hot air and cold air are expelled and produce an exhaust, which causes a forward thrust [6].
1. For a jet going slower than the speed of sound, the engine is moving through the air at about 1000 km/h (600 mph). We can think of the engine as being stationary and the cold air moving toward it at this speed.
2. Fan
3. Compressor increases the pressure of the air (and, to a lesser extent) its temperature.
4. Fuel tank
5. Combustion chamber increases the temperature of the air-fuel mixture by releasing heat energy from the fuel.
6. Turbine blades
7. The turbine blades are connected to a long axle (represented by the middle gray line) that runs the length of the engine. The compressor and the fan are also connected to this axle. So, as the turbine blades spin, they also turn the compressor and the fan.
8. Nozzle increases the velocity of the exhaust gases, so powering the plane.
Figure 3 and Table 1: Basic Component of an Engine: The figure shows an example of the inside of the engine. The table defines each parts of the figure with the basic explaination of each component.
Applications
1. Different Types of Engines
We have come a long way since the first plane engine model. The original engine was known as the Piston engine or also was call the reciprocation engine [3], which was a descendent of steam engines. The engine uses heat to produce steam pressure used to generate a rotating motion. In modern day aircraft engine have replaced steam with gas propulsion creating pressure within the engine.
Engineers have work to meet the demand of the public by creating 4 distinct type of engine that for each type of aircraft’s need.
Turbojets are commonly used in rocket due its power and efficiency at extreme high speed [3]. Turbonfans could be seen on majority of the current commercial aircraft, these and turbine engine with front- end fan. The fan sends air into the combustor, similar to a turbojet engine. However, the fan also sends a second stream of air through a larger cylinder entirely outside (and around) the engine core. This second stream of air provides additional thrust, cools the engine, and also serves to reduce engine noise. Turbofans are interchangeably referred to as bypass engines, in reference to this airflow that bypasses the combustor [3]. Turoprops uses an turbine to drive a rotating shaft, which in turn drives a reduction gear, which ultimately drives a propeller. The reduction gear is necessary to convert the high-speed shaft rotation into slower, functional propeller speed. Most of the power generated in a turboprop aircraft is used to drive the propeller [3]. Turbo shaft engines can are primarily used for helicopters and auxiliary power units. the engine does not provide any direct physical support to the helicopter’s rotors. The rotor is connected to a transmission, which itself is bolted to the airframe, and the turbo shaft engine simply feeds the transmission via a rotating shaft. The distinction is seen by some as a slim one, as in some cases aircraft companies make both turboprop and turbo shaft engines based on the same design [2].
Figure 4:Types of Engines: Top left Turbojets, top right Turbofans, bottom left Turboprops, and bottom right Turboshaft
References
[1]“Engines,” Engines. [Online]. Available: https://www.grc.nasa.gov/www/k12/ueet/studentsite/engines.html. [Accessed: 13-Jul-2016].
[2] “AIRCRAFT ENGINES – OPERATION AND TYPES OF PISTON, TURBOPROP, TURBOFAN REFERENCES ANIMATIONS & PICTURES,” Aircraft Engines Explained And Types Of Aviation Engines With References Animations Videos And Pictures. [Online]. Available: Http://Www.Aviationexplorer.Com/Aircraft_Engines.Html. [Accessed: 13-Jul-2016].
[3] “Piston Engine Aircraft vs. Turboprop Engine Aircraft,” Piston Engine Aircraft vs. Turboprop Engine Aircraft. [Online]. Available: http://www.shorelineaviation.net/news—events/bid/50442/piston-engine-aircraft-vs-turboprop-engine-aircraft. [Accessed: 15-Jul-2016].
[4] “Technology,” : Aviation: Benefits Beyond Borders. [Online]. Available: http://aviationbenefits.org/environmental-efficiency/technology/. [Accessed: 15-Jul-2016].
[5] “787 Propulsion System,” 787 Propulsion System. [Online]. Available: http://www.boeing.com/commercial/aeromagazine/articles/2012_q3/2/. [Accessed: 15-Jul-2016].
[6] “Read ‘Improving the Efficiency of Engines for Large Nonfighter Aircraft’ at NAP.edu,” 6 Other Considerations. [Online]. Available: http://www.nap.edu/read/11837/chapter/8. [Accessed: 15-Jul-2016].
[7] “Newton’s Third law of motion,”. [Online]. Available: https://www.grc.nasa.gov/www/k-12/airplane/newton3.html. Accessed: Jul. 21, 2016