Nitrogen and helium are widely used in modern rocket and aerospace engineering The main application areas include:

1. Various pneumatic valves and components are used as energy (helium is usefor liquid hydrogen cryogenic valve

2. Filling system for purifying and replacing liquid propellant with purified gas and alternative gas (system for replacing liquid oxygen with helium or hydrogen)

3. Pressurize the fuel tanks of rockets and aircraft and the fuel tanks on the fuel tanks to the ground to ensure the normal operation of the fuel system (helium or oxygen must be used to pressurize liquid oxygen)

Helium Gas

4. Start the rocket engine working on high-pressure nitrogen and immediately work on the turbopump (generated by the fuel gas generator after the turbopump engine is started);

5. Blow out the missile instrument cabin and electrical equipment requiring ground explosive fire extinguishing with nitrogen;

6. Rocket engine cleaning system (use ammonia or helium as required)

7. Clean and seal the surface piping system with nitrogen after filling The gas used by rockets and spacecraft in flight is stored in the titanium cylinder of the rocket. Before takeoff, the air used for ground equipment and missiles comes directly from the ground air supply system. The important components of rocket and aerospace equipment are air source and air supply system. Nitrogen is also used to check the tightness of rocket fuel tanks and engines. In order to ensure the normal operation of the turbopump in the rocket engine system, the turbopump must work under a certain net pressure to prevent cavitation. Therefore, the fuel tank must be pressed before the missile is launched. Nitrogen can be used as the power supply of the gas valve. Some pneumatic valves operating at liquid hydrogen temperature use helium. Nitrogen is an economical and clean gas Since the propellant nitrogen and steam are mixed on the platform, there is no risk of ignition and explosion, and there is no negative impact on the propellant system. For hydrogen and liquid oxygen liquid rocket engines, helium purification is required in some cases.