oil

• Lubricant


  Reduces friction between moving parts
• Fluid lubrication

  • Actual separation of the surfaces so that no metal-to-metal contact occurs
  • As long as the oil film remains unbroken, metallic friction is replaced by the internal fluid friction of the lubricant
  • Under ideal conditions, friction and wear are held to a minimum
• Oil

  Pumped throughout the engine to all areas that require lubrication
• Overcoming the friction of the moving parts of the engine

  Consumes energy and creates unwanted heat
• Reduction of friction during engine operation

  Increases the overall potential power output
• Turbine engine lubricating oils

  • High viscosity for good load-carrying ability
  • Sufficiently low viscosity to provide good flowability
  • Low volatility to prevent loss by evaporation at high altitudes
  • Should not foam
  • Should be non-destructive to natural or synthetic rubber seals
  • Formation of carbons or varnishes must be held to a minimum

  
• Synthetic oil

  Has a lower tendency to deposit lacquer and coke because it does not evaporate the solvents from the oil at high temperature
• Types of turbine engine oil

  • Type I - MIL-PRF-7808
  • Type II - MIL-PRF-23699F

  
• Wet-sump lubrication systems


  • Lubricating oil is stored in the engine proper
• Dry-sump lubrication systems


  • Use an external oil tank mounted on the engine or in the aircraft structure near the engine
• Types of turbine engine lubrication systems

  • Pressure relief system
  • Full flow system
  • Total loss system
• Main function of the oil system in turbine engines

  Cooling the bearings by carrying the heat away from the bearing by circulating oil around the bearing
• Exhaust turbine bearing


  • The most critical lubricating point in a gas turbine engine because of the high temperature normally present
• Turbine lubrication system components

  • Oil Tank
  • Oil Pump
  • Turbine Oil Filters
  • Oil Pressure Regulating Valve
  • Oil Pressure Relief Valve
  • Oil Jets
• Oil tank in dry-sump systems

  • Contains most of the oil supply, a small sump is usually included on the engine to hold a small supply of oil
  • Contains the oil pump, the scavenge and pressure inlet strainers, scavenge return connection, pressure outlet ports, an oil filter, and mounting bosses for the oil pressure gauge and temperature bulb connections
• Oil pump


  • Designed to supply oil under pressure to the parts of the engine that require lubrication, then circulate the oil through coolers as needed, and return the oil to the oil tank
  • May have pressure supply element and scavenge elements, or a single function of either supply or scavenge
• Types of oil pumps

  • Gear pump
  • Gerotor pump
• Oil filters


  • Remove foreign particles that may be in the oil
  • Filtering elements come in a variety of configurations and mesh sizes measured in microns
  • Located close to the pressure pump and consist of a filter body or housing, filter element, a bypass valve, and a check valve

  
• Oil pressure regulating valve


  Keeps the pressure fairly constant in the oil system

  
• Oil pressure regulating valve

  • Has a valve held against a seat by a spring, adjusting the spring tension changes the pressure at which the valve opens and the system pressure

  
• Oil pressure relief valve


  • Relieves pressure only if it exceeds the maximum limit for the system, bypassing the oil back to the inlet side of the oil pump

  
• Oil jets


  Deliver the oil in the form of an atomized spray to the bearing compartments and rotor shaft couplings
• gasoline is the most common product made from crude oil
• oil is made up of hydrocarbons, which are molecules containing only carbon and hydrogen atoms
• oil is used to make gasoline, diesel fuel, heating oil, asphalt, tar, kerosene, lubricants, plastics, waxes, solvents, and other products.
• coal was formed from the remains of plants that were buried millions of years ago
• the first oil well was drilled by edwin drake in titusville, pennsylvania
• The lighter fractions are collected first during distillation
• Distillation separates different components based on their boiling points
• Crude oil is refined into gasoline through distillation
• hydrocarbon chains can be straight or branched
• the longer the chain, the more viscous (thicker) the oil will be
• viscosity refers to how easily a fluid flows
• natural gas is found deep underground mixed with oil or coal deposits
• crude oil is pumped out of underground reservoirs through large metal tubing called casing
• the three main types of fossil fuels are coal, petroleum (crude oil), and natural gas
• casing protects the hole from collapsing or being damaged by rocks falling into it
• fossils are the remains of ancient organisms preserved in rocks
• heavier fractions are collected last during distillation
• Crude oil contains many impurities such as sulfur, nitrogen, oxygen, metals, and water