Is the SR71 Blackbird reconnaissance aircraft flying so high because of the use of oxidizers?

The one on the 12th floor upstairs is a typical one who knows one and doesn't know the other.

It is a fact that aircraft engines can only operate in the presence of ambient oxygen. Aero engines used in aircraft are "air-sucking engines", or air-breathing engines for short, and air must be sucked in as an oxidizer (accelerant) for fuel. Although the SR71 flies at a high altitude, it does not leave the atmosphere, although the air at high altitude is thin, but its engine still relies on air to achieve combustion - when SR71 reaches an altitude of 10,000 meters, the speed has reached more than Mach 3, and the air flow obtained by the engine at this speed is quite large, so to a certain extent, it makes up for the impact of thin air.

If the airfield of SR71 is erected at an altitude of more than 20,000 meters and the flight speed starts from 0, then it will not be able to fly anyway. In fact, when the engine J58 of the SR71 is flying at high speeds, only part of the air from the air intake hole enters the combustion chamber, while the rest is directly introduced into the afterburner, causing a ramlash effect; The remainder is introduced into the exhaust stream to increase the air flow and increase the thrust.

I would like to make it important to note that, in addition to the air introduced, the engine of the SR71 also needs a special accelerant - triethylborane (I remember the name of the chemical as I remember). The fuel JP-7 used in SR71 is a fuel with a high ignition point, which is not lit by ordinary engines, and triethylborane is a kind of ** liquid that spontaneously ignites when exposed to air, and the engine of SR71 needs to inject this accelerant into the combustion chamber and mix it with the fuel to achieve ignition.

Therefore, at an altitude of 10,000 meters, it is still very difficult for the engine of SR71 to operate without the help of triethylborane. However, even so, the SR71 is still not allowed to exceed the altitude of 10,000 meters when performing the mission, because at this altitude the engine may stall at any time.

As for other liquid and solid accelerants and propellants, they are basically used in rocket engines, and rarely in aero engines. This is because rocket engines need to operate outside the atmosphere, so they must carry their own accelerants and oxidizers (such as nitric acid, liquid nitrogen, etc.). There is no record of this in the current information of SR71, although SR71 uses triethylborane and has sufficient air flow, the possibility that SR71 uses other oxidants to assist combustion.

In addition, although the SR71 also carries its own oxygen storage device, it is not used for the engine - the SR71 has a total of three 10-liter liquid oxygen storage converters, two for the cockpit and one for backup.

Damn, what kind of aircraft does not rely on oxidants? Can an airplane's engine work without oxygen in the air?

Not so exaggerated at all. The J58 uses JP7 fuel, which is the aviation fuel that was very popular in the U.S. military.