Most of the cars or other machinery and equipment burn gasoline or diesel, while the airplane flying in the air burns not gasoline or diesel, but kerosene. Why?
There is only one reason why airplanes burn kerosene instead of gasoline and diesel. Many people think that it is very cold at high altitudes. It is cold to minus 50 or 60 degrees. The display of the airliner shows this, and you can feel it when you stand on Mount Everest. Here comes the question: Why are falling meteors or satellites burnt to ashes? That’s right, when flying at supersonic speeds, air friction heat is greater than air cooling.
Take the US Army Blackbird reconnaissance aircraft as an example. The body expands significantly due to high temperature during flight, so gasoline and diesel will become gas at that temperature unless you change the fuel tank to a bulky one. The liquefied petroleum gas steel tank prevents the gasification of gasoline and diesel.
Kerosene is different. Depending on the production process, its gasification temperature can reach 130,150,240 ℃ or even higher. It can be heated without gasification, and there is no need to put heavy steel tanks on the back of the fighter.
Civil aviation airliners (except Concorde aircraft) are slower than the speed of sound, and the air cooling effect is greater than the frictional heating effect. So The body became cold, and it is difficult to gasify the fuel at high altitudes and low air pressure. Wide distillation range (low gasification point) kerosene can be used. Contains a lot of gasoline components, in other words, there is no problem with burning gasoline.
The situation of supersonic cruise fighters is just the opposite. The airframe exceeds 100°C during flight and can only use heavy kerosene. This kerosene already contains a lot of diesel components, and basically contains no gasoline or only a small amount of macromolecular gasoline, and it is not easy to gasify.
Some people may question: Why are the spaceship rockets are filled with pre-cooled liquid hydrogen and liquid oxygen, which are easier to vaporize? we will discuss about this one a different article.