Researchers from the University of Southern California (USA) have obtained experimental confirmation of the theory that it is possible to control the air-fuel flow using shock waves. This is necessary to solve the key problem in the creation of hypersonic ramjet engines (scramjet or "scrumjet" in English terminology - ed. Tekkult). Until a solution is found, the cars will fly at speeds of 6-9 Max, with design capabilities above 20 Max.
The scramjet does not have a traditional oxidizer compartment; its functions are performed by atmospheric air, which, due to the enormous speed of the machine, enters the combustion chamber very quickly and in a compressed state. The combustion of a mixture of fuel and air occurs at supersonic speeds, the entire system is designed only for continuous operation, while the aircraft cannot move slower than a certain threshold value. In such a situation, a complex engineering problem arises: how to inject fuel so that uniform mixing with air occurs, followed by instant detonation?
Scrumjets use compressed incoming air
Californian scientists have focused on scrumjet airflow control, starting from the fact that no mechanism can be placed inside the air intake. Firstly, they will not withstand the loads, and secondly, this complicates the design and increases the risks. Scramjet engines are even better than turbojet engines because it does not have a rotating turbine and other vulnerable components. Therefore, as a tool for influencing the air flow, American engineers proposed using a shock wave.
Laboratory experiments have shown that a shock wave can effectively crush an air flow, “tear off” fragments from it, and at the same time slow them down. This allows you to adjust the ideal fuel injection pattern and obtain an air-fuel mixture with optimal parameters, increasing the engine efficiency. Now it is necessary to design a new combustion chamber to effectively use this technology.