China has successfully tested a prototype hypersonic engine with an oblique shock wave

 

China has successfully tested a prototype RAMJET with an oblique shock wave

The technology, which was rejected by the US military decades ago, has been successfully tested in China. A group of engineers from the country's leading aerospace research centers has achieved a breakthrough in the development of an oblique shock wave hypersonic engine powered by conventional liquid fuel. An experiment simulating flight conditions at a speed of Mach 8 and an altitude of 30 km proved the technical feasibility of the concept for military use.

The ground test was conducted by scientists from the Chinese Research Institute of Rocket Technology (CALT) and Northwestern Polytechnic University, the details were published in the May issue of the Journal of Aerospace Power. After ignition, the engineers observed explosive waves in the combustion chamber of the engine for more than two seconds. This test simulated the operation of a ramjet engine with oblique standing detonation (Sodramjet) at a speed of Mach 8 and an altitude of 30 km. Aviation kerosene of the RP-3 brand was used as fuel.

The conducted test is a significant technical achievement, according to the SCMP. In December 2023, the Chinese Academy of Sciences reported a similar experiment, but then the detonation lasted only 50 milliseconds and was classified as an anomaly by a number of experts. This time, the detonation was steady and lasted 40 times longer.

The sensors showed a pressure surge after detonation to 272 kPa, which is more than ten times the pressure before ignition. The results of the chemical simulation coincided with the results of real tests and confirmed the creation of significant thrust. According to Yang Yang, the group's lead researcher, the gorenje zone remained stable during the 2.2-second test period.

The tests confirmed the possibility of practical use of liquid-fuel RAMJET engines with oblique standing detonation. With this type of detonation, the shock wave propagates at an angle of the surface and can "stand" in one place without moving. Theoretically, the concept can find application in new varieties of RAMJET engines.

This idea was first proposed in 1958 by scientists from the University of Michigan with the support of the US Air Force. NASA then studied it in the 1970s, hoping to achieve hypersonic speeds. However, development has stalled due to difficulties in maintaining stable detonation and controlling the mixing of fuel and air under extreme conditions.

In May, the American company Venus Aerospace announced successful flight tests of a rotating detonation rocket engine (VDD), promising to reduce fuel costs and make passenger hypersonic flights affordable. So far, airborne missiles have never taken off over the territory of the United States.