Sample Aviation Essay Paper on Types of Aviation Fuel

Types of Aviation Fuel

Introduction

Aircrafts that are powered require fuel to operate the engine that propels other vital components thus effective movement. The growing of the international tourism industry, the development of the aviation sector and affordable fares among other factors has led to high consumption of aviation fuel (Mazraati, 2010). Aviation fuels vary in boiling point, pressure and other properties based on the type of aircraft they are used in and the type of work that aircraft is designed to carry out, for instance, military activities. The types of engines used in aircraft of different types of service require fuels of diverse specifications because of their different physical and chemical properties. Aviation fuel is mostly consumed for domestic aviation services though the share is gradually declining with growth in international traffic growth. There are several types of aviation fuel which comprise of reciprocating-engine and turbine-engine fuel. Aviation gasoline and jet fuel are the most common types of fuel which is used in aircrafts. Interchanging the type of fuel that is used in certain aircrafts can have adverse effects on the operation of the aircrafts.  This essay analyzes the different types of aviation fuel and the aircrafts in which those types of fuel are the most appropriate.

Aviation fuels comprise of hydrocarbon substances, for instance; paraffin’s, cycloparaffins and additives that are determined by the specific uses of the fuel.  Paraffin’s and cycloparaffins are the major components whereby Paraffin’s have a high hydrogen-to-carbon ratio, with a high heat release per unit of weight and a cleaner burn than other hydrocarbons thus making them to operate under extreme conditions.  On the other hand cycloparaffins have a lower hydrogen-to-carbon ratio, which leads in less release of heat per unit of weight but increases the fuel’s density. Additives such as antioxidants, metal deactivators, fuel system icing inhibitors, corrosion inhibitors, and static dissipater additives are all present in limited quantities in jet fuels in order to improve the effective performance of the aircrafts. Jet fuel is produced from the same cut of the barrel called middle distillate as diesel fuel and heating oil and thus it is one of the most difficult refined petroleum products to hedge. The compounds that are found in the fuels that are used in aircrafts have properties that make it possible for the engine to work properly thus enabling effective movement and balancing of aircrafts

AVGAS

This type of fuel is designed for use in aircraft engines and contains hydrocarbon substances refined from crude oil by distillation. This type of fuel is a blend of several hydrocarbon substances, each with diverse boiling points and different levels of volatility. The volatile compound in this type of fuel makes it to vaporize thus delivering the power through the acceleration of the engine. The nature of the engines of most aircrafts makes it necessary for them to have special fuel types so as to prevent complications like engine fails. Aviation gasoline is commonly used in aircrafts that have small pistons that make it possible for effective engine functioning thus effective movement.  Different engines of different aircrafts are designed in such way that they can only use certain types of fuel. If other types of fuels are used rather than the designated ones then the engine of that aircraft is bound to fail and cause technical problems to the aircraft.Avgas is gasoline fuel for reciprocating piston engine aircraft which is very volatile and is extremely flammable at normal operating temperatures” (Wagman, 2013).  

 Avgas grades are defined primarily by their octane rating whereby two ratings are applied to aviation gasoline’s which results in a multiple numbering system, for instance, Avgas 100/130 which means that mixture performance rating is 100 and the rich mixture rating is 130. We have several grades of aviation gasoline that are classified based on octane rating meaning that the higher the rate of octane the more efficient the fuel. Cycloparaffins have a ring structure that is saturated which helps in decreasing the hydrogen-to-carbon ratio and thus lowering their heat release per unit weight. The ring is also essential in lowering the density of the fuel and thus making it possible for it to burn under conditions that are extreme. Their primary advantage is that, in general, their freezing points are lower than comparable paraffin’s with the same number of carbon atoms.   The gasoline used in the engines of aircrafts must support uninterrupted combustion hence burning of gasoline in the engine of aircrafts ensures minimal engine wear hence making the engine to last for long. The uninterrupted combustions of gasoline that is used in the aircrafts ensure that the engine does not fail when navigating the skies.  The propulsion of the engines of aircrafts requires fuel that burns at high temperature and pressure thus effective movement and balance in the air. Additives are lesser in the fuel that is used in the engine of the aircrafts so as to minimize rusting in product pipelines and fuel storage tanks.  The rating and octane composition of avgas makes it possible for them to support easy combustion in very high temperatures that aircrafts are designed to operate.

Volatilitymeans the rate at which a substance turns from water into a gas hence isone of the vital characteristics of the fuel of an aircraft. Highly volatile fuel is desired for aircrafts engines that are reciprocating. Engines that reciprocate operate under high temperatures and pressure and thus require fuel that is highly volatile so as to withstand the pressure generated. Fuel which has low volatility does not easily explode and vaporizes slowly thus causing problems in engine starting and can also result to the irregular distribution of fuel to the cylinders thus bringing problems to the effective functioning of the aircraft. Reciprocating Engine Fuel is a mixture of many hydrocarbon compounds, each with diverse boiling points and volatility rate and the solubility of gases in fuels is crucial to the operation of the engines. High evolution of gases during climb can cause loss of fuel due to decreased pressure. The fuels of aircrafts are supposed to be highly volatile because of the conditions in which the aircrafts operate, for instance the extreme temperatures and pressures that are found in the skies. The loss of fuel that can be caused by reduced pressure during the time of climbing can result in complications to the aircraft, for instance, mechanical problems. Carbon dioxide, unlike the other gases, decrease in solubility with increasing temperature and pressure, and the solubility of this gas is very high in the fuel systems of aircrafts.

Reciprocating Engine Fuel is also vapor lock meaning that it vaporizes in the fuel line and the carburetor which is caused by hot fuel and low pressure that is found in the engine of most of the aircrafts. When an aircraft climbs rapidly, the pressure on the fuel in the tank reduces whereas the fuel is still warm thus causing an increase in fuel vaporization that can leads to vapor lock.  The use of boost pumps which are found in the fuel tank can be used to prevent vapor lock because as fuel vaporizes, it draws energy from the environment and thus changes to vapor. Vapor lock that is generated is not good for the effective movement and operation of the aircraft because if the vapor lock that occurs is left unchecked, then the plane will have mechanical problems because of the pressure and temperatures that are generated as a result of the problem. They have also been found to improve the lubricity of some fuels and are mandatory in certain military fuels for this purpose. Addictives are diethylene glycol solutions that work as antifreeze because they dissolve in free water as it comes out of the fuel and lower its freezing point. The lowering of the freezing point is crucial because it helps in the effective movement and navigation of the aircraft in space.

Avgas 100, It is commonly used in the standard high octane fuel for aviation piston engines because it has a high lead content and is dyed green. Its high lead content makes it ideal for the operation of the engines of most aircrafts which operate under high temperatures and pressure. They are all the same except for the octane rating whereby several piston-engine aircraft were made for octane grades other than 100LL. We also have other alternatives fuel that are used in aircrafts other than avgas and jet fuel that are the most common in the aviation industry.

Avgas 82 UL, this is designed to run on unleaded because of the world market of gasoline and its properties and characteristics. This presents problems in engines which are designed to run on 80/87 fuel; the low lead 100 octane fuel contains more lead than the 80 octane fuel the reason that it is environmental friendly as compared to other types of aircraft fuel which are pollutants of the environment and affect the well being of living things. It could be made available as an interim measure prior to the introduction of an unleaded high octane fuel, should it be necessary to address environmental concerns about leaded fuels.  ASTM D is constrained by the same specification requirements as Avgas 100LL because of their unique properties and the temperatures that is the fuel is made to work. AVGAS with no TEL is environmental friendly as compared to other types of aircraft fuel and thus it AVGAS with no TEL is sought for the aviation fleet of the future for the reason that it is environmental friendly as compared to other types of aircraft fuel.

The use of filters in the different stages of transfer and storage of AVGAS removes most foreign sediment from the fuel and thus making it pure. Filters and strainers in the aircraft fuel system can successfully capture any remaining sediments that may interfere with the effective functioning of the aircraft. The purity of Avgas is compromised by water whereby Water settles into the sumps and once in the tanks, dirt settle into the fuel tank drain sumps and are removed before flight thus affecting the operation of the aircraft.  If water is dissolved then it cannot be removed by draining the sumps and filter bowls before flight, however, there may be enough water for icing as the aircraft climbs and fuel is drawn out of the tanks, the fuel supply cools. These can clog filters and disrupt fuel flow to the engines and hence cause problems by interfering with the functioning of the aircraft. Both AVGAS and jet fuel have this type of water impurity issue leading to icing that must be monitored and treated on a regular basis and thus Avgas is used in small piston engine powered aircraft within the General Aviation community, for instance, private pilots, flight training, flying clubs and crop spraying.

Turbine-engine fuel/jet fuel

Jet fuel is kerosene-based and contains special additives free of sulfur and with shorter and branched carbon-chains which are more resistant to thermal breakdown; it is used in rocketry usually with liquid oxygen as the oxidizer. Different jest are designed to use a different types of fuel depending on the activities they are made to carry out, for instance, commercial use and military activities. Diesel and kerosene should not be taken as fully interchangeable fuels at present, because kerosene has no cetane-number specification and thus it may have large ignition delays (producing lots of un-burnt emissions and engine rough-running by high-pressure peaks); besides, kerosene has less lubricity and diesel-fuel less cold-start ability (Sarnecki, 2014). The presence of components which are found in the kerosene in jet fuel makes it possible for the fuel to easily burn when the plane is moving thus avoiding mechanical problems. Jet fuel is one of the most difficult refined petroleum products to hedge for the reason that it is produced from the same cut of the barrel called middle distillate as diesel fuel and heating oil, but unlike those markets where the buyers are small, numerous and scattered widely, the jet fuel market is concentrated in a handful of large airports, some of which have direct dedicated pipelines running from nearby refineries. The bonded carbon chains that are found in the fuel that crucial in the aircrafts prevents engine fail and thus effective movement of the plane. The low freezing point of the compounds of the fuel makes it possible for it to operate under extreme conditions, for instance, low or high temperatures. There are many types of fuels which are used in the engine of jets, for instance, jet fuel A, jet fuel B among others. Jet fuel is used for commercial (Jet A-1, Jet A, and Jet B) and military (JP-4, JP-5, JP-8.) jet propulsion whereas aviation gasoline is used to power piston-engine aircraft.  The composition of the varied grades of the jet fuel is diverse based on the type of aircraft that the fuel is used. They are basically mixtures of kerosene and gasoline (half and half for JP-4, 99.5% kerosene for JP-5 and JP-8, 100% kerosene for Jet A-1), plus special additives (1.2%): corrosion inhibitor, anti-icing, anti-fouling, and anti-static compounds. Jet A-1 comprises hydrocarbon chains with 9 to 15 carbon atoms. Jet B (also named JP-4, with composition distribution from 5 to 15 carbon chains), is used in very cold weather, and in military aircraft. The existence of the carbon chains in the fuel is crucial to aircrafts which work in conditions which are not ideal for example military operations. The accumulation of hazardous materials into the tank can affect the effective movement of the aircraft because it may lead to the development of mechanical problems. This is kept within acceptable safe limits by avoiding very high rates of fuel flow in the refueling system and by controlled distribution of the fuel in the tanks, such as bottom loading and the use of diffusers on pipe outlets. Some countries around the world insist on the use of static dissipater additives in the fuels to increase the fuel electrical conductivity. Electrical conductivity in the engine of aircrafts is essential for the effective operation of the aircrafts and their navigation in the air.

Jet fuel is used for commercial and military jet propulsion whereas aviation gasoline avgas is used to power piston-engine aircraft and thus there are mixtures of kerosene, kerosene for JP-5 and JP-8, 100% kerosene for Jet A-1 plus special additives. Corrosion inhibitor, anti-icing, anti-fouling, and anti-static compounds hence Jet fuel comprises hydrocarbon chains with 9 to 15 carbon atoms and a Jet with composition distribution from five to fifteen carbon chains which are crucial in very cold weather, and in military aircraft. Commercial jet fuel has a specification requirement of -400Fmaximum but that for military fuels is lower. Air Force bombers require an even lower freezing point, -7pFmaximum, since long flights at high altitudes permit the fuel to reach lower temperatures. The jet fuel properties which are of greatest concern with the new fuels is the freezing point, combustion properties, and stability, both thermal oxidative and storage hence jet fuel is not a single hydrocarbon, its’ composition vary depending on production plant, production process and crude oil source. The use of non-hydrocarbon compounds in aviation fuel is crucial for the reason that they aid in reducing temperatures when they aircraft operates under very high pressure. Jet fuel can hold so much water, referred to as its saturation limit. However, if the water has been exposed to freezing temperatures for several hours, it may be impossible to drain during the next refueling stop. Microbes are sustained by fuel and water thus avoiding having fuel in a storage tank for a prolonged period of time for the effective function of the engines.

Engines of aircrafts are designed to use specific types of aviation fuel for effective functioning and movement. If fuel an aircraft that is designed to use a specific type of fuel is refilled with another type then this can result to engine knock. Jets and other normal aircrafts used different types of fuel and an interchange of the fuel type can have negative effects on the effective functioning of the aircraft. Aviation fuel is mostly consumed for domestic aviation services though the share is gradually declining with growth in international traffic growth. Aviation fuels vary in properties and characteristics based on the type of aircraft they are used in and the type of work that aircraft is designed to carry out, for instance, military activities.  The proportion of each type of fuel varies based on the specific necessities of the engine of each type of aircraft and the distance it has been designed to travel.

References

Mazraati, M. (2010). World aviation fuel demand outlook. OPEC Energy Review, 34(1), 42-72. 

Sarnecki, J. (2014). Jet fuels diversity. Journal of KONES21(4), 433-438.

Wagman, D. (2013). Reciprocating Engines Continue to Be Flexible Workhouses. Power, 157(10) 72-74.