Cars use gasoline but jets use something closer to diesel, maybe kerosene, that’s less combustible. Wouldn’t they need a _more_ volatile or explosive fuel to get the most thrust for performance?
In: Engineering
Crude oil is made of several different chain of carbon, the chain in the 5 to 7 range are very light so they vaporize first and those are used as solvents and other chemical. Chain 7 to 11 is a bit heavier so they evaporate next and that’s gasoline. Next is chain 12 to 15 which is kerosene, then you have a bunch of other product like diesel, lubricant, oil, etc. They are not more or less refined than the others, they are just lighter or heavier chain of carbon, each with their own physical properties.
Gasoline have a decent energy density of 124 thousand BTU per gallon, it also have an high octane which make it work well in compression engine. What this mean is a low octane fuel would ignite in the high pressure of a piston engine before the fire from the ignition would reach it, this would create issues called knocking, which you don’t want.
Kerosene have an even higher energy density of 132 thousand BTU per gallon. It have a low octane, which mean it would be bad in compression engine like a pistol. But in a turbine, you don’t have this problem. On top of this, Kerosene have a lower freezing temperature than gasoline which is extremely important for an aircraft that might be going in high altitude where the temperature is low.
That’s why you can have a turbine on a land vehicle (like the Abrams) able to use several type of fuel The turbine make it ok for kerosene and since it’s not in high altitude, gasoline won’t freeze.
When you say volatile and explosive, you have some misconception. Volatile is how easy it evaporate at normal temperature, but engine don’t operate at normal temperature, making this physical property completely irrelevant to the energy content of the fuel.
As for explosive, well there is a misconception here. Explosiveness is the rate of oxidation (aka the rate at which it burn) and all those fuel have a low rate of oxidation, that’s why if you lit up gasoline on the floor it will only burn. It’s only when you a pressure that you can create an explosion out of fuel. Contract that to real explosive which oxide extremely fast and can create explosion on their own at ambient pressure.
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