World’s most powerful wind tunnel opens in Beijing, here’s how it will boost China’s hypersonic ambitions

Beijing, China

China has recently completed the construction of the most powerful wind tunnel in the world, located in the mountainous Huairou district of northern Beijing. The wind tunnel, called JF-22, has a diameter of 4 metres (13 feet) and can generate incredibly high airflow speeds of up to 10 kilometres (6.2 miles) per second. This makes it capable of simulating hypersonic flight conditions up to Mach 30, which is 30 times the speed of sound. 

Tunnel to support China’s hypersonic ambitions

The Institute of Mechanics, which owns the facility, stated that the JF-22 wind tunnel will play a crucial role in advancing China's hypersonic ambitions. The tunnel will support research and development efforts for China's space transport system and hypersonic aircraft, as well as for military purposes.

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The Chinese government has set ambitious goals to deploy a fleet of hypersonic aircraft by 2035, capable of carrying passengers into space and reaching any point on Earth within an hour.

Why is hypersonic tunnel important for China?

Hypersonic flight poses significant challenges, including extreme heat and pressure, stable flight trajectories, and passenger safety. At hypersonic speeds, air molecules surrounding an aircraft become highly compressed and heated, leading to molecular dissociation, where the molecules break apart and react with each other. Understanding this complex physics is essential for the development of hypersonic aircraft.

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Wind tunnels, like the JF-22, provide a controlled laboratory environment for studying hypersonic flight phenomena. Researchers can study how hypersonic vehicles interact with their surroundings and develop new technologies to enhance performance and safety. Additionally, wind tunnel testing helps identify potential problems or design flaws before building and flying actual vehicles, reducing the risk of failure or accidents and hence saving resources.

How powerful winds are generated in the hypersonic tunnel?

The JF-22 wind tunnel stands out due to its innovative approach. Instead of using traditional expansion methods to generate airflow, the lead scientist, Professor Jiang Zonglin, proposed a new shock wave generator called a "reflected direct shock wave driver." 

This system utilises a series of precisely timed explosions to create shock waves that converge and generate high-speed airflow in the wind tunnel. Although this method has drawbacks such as noise, air pollution, and safety concerns, it allows for rapid and intense bursts of energy required for hypersonic testing.

The JF-22 wind tunnel has been evaluated by a team of 16 independent experts, who praised its performance and labelled it as "world-leading."

Together with the JF-12 wind tunnel, which simulates flight conditions up to Mach 9, these facilities provide a comprehensive experimental platform for testing near-space vehicles. By combining the data from both wind tunnels, researchers can gain a better understanding of materials and designs under various flight conditions, ultimately improving the performance and reliability of hypersonic weapons and aircraft.