JF-22 in China is now the world's most powerful hypersonic wind tunnel

A civilian application of the technology would enable high-speed air travel for the common, an area of focus for the Chinese government. It has envisaged deploying a fleet of hypersonic aircraft by the year 2035.

Going beyond Mach 5

With China leading the research in hypersonics, the country is raising the bar on what can be achieved and going beyond the speeds of Mach 5. However, when a body travels at such a speed, air molecules around it become highly compressed and heat, a process referred to as molecular dissociation.

It is also possible that the air molecules might break down into their constituent atoms or form a few chemicals altogether. It is, therefore, essential to understand the complex flows associated with this phenomenon before building aircraft or weapons that go beyond these speeds.

Wind tunnel testing is a crucial tool that can help spot design flaws or risk of failure before a full-scale prototype is even built. NASA's Langley Research Center in the U.S. has a wind tunnel where speeds up to Mach 10 can be reached. However, China has just topped these speeds by a mile.

JF-22, the Mach 30 wind tunnel

Built over five years, the JF-22 tunnel has a diameter of 13 feet (four meters) and can generate airflow speeds up to 6.2 miles (10 km) per second. In comparison, the NASA wind tunnel has a diameter of 2.62 feet (0.8 m).

A larger cross-section enables researchers to put larger objects into the tunnel to obtain more accurate flight data. For instance, the diameter of an intercontinental missile is also 13 feet, so researchers could practically put an entire missile and test the impact of sending it at speeds much higher than Mach 5.

The wide diameter of JF-22 makes generating high-speed winds an extremely energy-intensive process. So, Chinese researchers devised an innovative way to do it instead. Instead of relying on conventional methods such as sending high-pressure gas into a low-pressure chamber to create supersonic airflow, these researchers used precisely timed explosions to generate shock waves that reflect off each other and converge at a single point.

The method also allows for creating more tailored air flows that can be used for testing other types of vehicles or materials. The JF-22 facility is built at the exact location of understanding China's JF-12 wind tunnel that supports testing up to the speeds of Mach 9. By combining data from both facilities, China hopes to advance its expertise in the hypersonic domain further, the report said.