Leading the world! The JF-22 super-high-speed wind tunnel, a national heavy weapon, passed the acceptance inspection. Let’s read the expert’s interpretation!

Not long ago

Construction in Beijing Huairou Science City

JF-22 super high speed wind tunnel passed the acceptance

Aroused great concern

The performance indicators of this national heavy equipment

What level has it reached internationally?

What experiments will it carry out?

Equivalent to about 30 times the speed of sound! Reporters visit the JF-22 wind tunnel

Walking into the National Key Laboratory of High Temperature Aerodynamics for Space Flight in Beijing Huairou Science City, the reporter saw the JF-22 hypersonic shock wave wind tunnel that had just passed the acceptance inspection. It is 167 meters long and has internationally leading performance indicators, providing strong support for the development of space shuttle systems and hypersonic aircraft.

As the cradle for developing a new generation of aircraft, the JF-22 hypersonic wind tunnel can reproduce flight conditions at altitudes of 40 to 90 kilometers and a maximum speed of 10 kilometers per second, equivalent to about 30 times the speed of sound.

According to Jiang Zonglin, a researcher at the Institute of Mechanics of the Chinese Academy of Sciences and the person in charge of the Huairou shock wave wind tunnel project:

1. The flow field blown by the JF-22 is about 2.5 meters in diameter. Generally, the largest one abroad is 1.5 meters in diameter, which can accommodate larger aircraft;

2. When the Mach number is 10, the JF-22 can reach 40 milliseconds, which is several times higher than the advanced level of similar domestic and foreign counterparts, and the accuracy of the experimental results is also higher;

3. JF-22 has high total temperature, high total pressure and high performance. Currently no other wind tunnel in the world can compare with it.

How does a wind tunnel work? What are the characteristics of a shock wave wind tunnel?

The JF-22 hypersonic wind tunnel is also called the detonation-driven hypersonic high-enthalpy shock wave wind tunnel. The name sounds very high-end. As the cradle of the aircraft, how does the wind tunnel work? What are the characteristics of the shock wave wind tunnel? What experiments will be carried out? Let's listen to the interpretation of experts↓↓↓

Aiming at the round-trip flight technology between the earth and the sky, the scientific research team first carried out research

The research and development goal of the JF-22 hypersonic wind tunnel is mainly to solve the experimental research problems of hypersonic flight technology. After the project was accepted, the research team first carried out the research on the round-trip flight technology between the earth and the sky. According to Han Guilai, a researcher at the Institute of Mechanics of the Chinese Academy of Sciences and the site manager of the Huairou shock wave wind tunnel, "We are currently studying a two-stage or multi-stage orbital aircraft. The rocket takes off and lands vertically. In the future, we will use the aircraft to take off and land horizontally, and then fly to an altitude of, for example, 30 to 40 kilometers, and then release the second stage, and then fly upwards, forming a relay mode, called two-stage or multi-stage orbital entry. Therefore, we are also preparing for such a corresponding separation scheme experiment recently, mainly to explore the separation process of the lower stage and the upper stage."

Jiang Zonglin also introduced that "in terms of wind tunnel research, we have solved the concept of hypersonic separation. From an experimental point of view, we have successfully and safely solved this problem. In addition, we also need to do separation at different flight speeds. With these data, it will be very easy to design aircraft and conduct flight experiments."

JF-12 and JF-22 cover all "flight corridor" experimental capabilities

The JF-12 reproduction wind tunnel successfully developed in 2012, with a total length of 265 meters, became the world's largest and most advanced shock wave wind tunnel at the time. The JF-22 super-high-speed wind tunnel also recently completed acceptance and began formal operation.

The JF-12 reproduction wind tunnel and the JF-22 hypersonic wind tunnel are the largest and most advanced shock wave wind tunnels in their corresponding fields, making my country the only country in the field of hypersonics with the experimental capability to cover the entire "flight corridor".

The JF-12 reproduction wind tunnel and the JF-22 super-high-speed wind tunnel can achieve experimental conditions of 1.5 to 3 kilometers per second and 3 to 10 kilometers per second respectively, together forming an aerodynamic experimental platform covering Mach numbers of 5 to 25 and flight altitudes of 25 to 90 kilometers.

Jiang Zonglin said that wind tunnels can be used to test hypersonic engines. "Our laboratory has proposed a new type of engine, called a stationary oblique detonation engine. We have already achieved Mach 7 to Mach 9 with the JF-12. It seems that the new engine has a 50% higher thermal efficiency than traditional engines and stable combustion. The JF-22 is going to go from Mach 9 to Mach 16. If such an engine is completed, I think it will be a great boost to our country's next step in aerospace technology."

In addition, the scientific research team will also use the shock wave wind tunnel experimental platform to carry out research on gliding vehicles, earth-to-space round-trip vehicles, multi-stage orbital vehicles, etc., to support and serve the major needs and key technology research in the country's hypersonic science and technology field.

China has taken a different approach to the development of a research team. As early as August 2021, CCTV Military Channel also introduced the JF-22 wind tunnel that was under construction at the time. In the 1950s and 1960s, under the strategic deployment of Qian Xuesen and Guo Yonghuai, the Institute of Mechanics of the Chinese Academy of Sciences established China's first hypersonic shock wave wind tunnel research team. The team abandoned the internationally accepted technology at the time and took a different approach to achieve theoretical innovation in detonation drive through decades of technical research.

In the late 1990s, Jiang Zonglin (project leader of the shock wave wind tunnel) led the team to start research on a large-scale detonation-driven shock wave wind tunnel.

The JF-12 wind tunnel was successfully developed in 2012. Now, the JF-22 wind tunnel has passed acceptance and started operation.

What is a wind tunnel?

NASA's official website has a down-to-earth definition of a wind tunnel: a wind tunnel is a large tube with air flowing inside. Simply put, a wind tunnel is a pipe-shaped test device that artificially generates and controls airflow to simulate the flow of gas around an aircraft or object and various complex flight conditions in the air, and can measure the effect of airflow on objects and observe physical phenomena. It is the most commonly used and most effective tool for aerodynamic testing, and is a "green channel" for the development, shaping and production of modern aircraft, missiles, rockets, etc. A wind tunnel can also be seen as an artificially created "sky" on the ground. Wind tunnels are usually used to test aircraft, cars, spacecraft, and almost all engineering applications related to the flow of surrounding air, even golf balls.

▲Simplified diagram of wind tunnel principle

The wind tunnel is mainly composed of the tunnel body, drive system and measurement and control system. The form of each component varies depending on the type of wind tunnel. The experimental section is mainly used to measure and observe the model. There are stabilization sections and nozzles upstream of the experimental section. The function of the stabilization section is to improve the straightness of the airflow and reduce the turbulence of the airflow, while the function of the nozzle is to accelerate the airflow to the required speed. There is generally a diffuser downstream of the experimental section to reduce the flow rate and residual velocity loss, and an exhaust section to guide the airflow or reflux section outside the wind tunnel to the entrance of the wind tunnel.

▲Basic structure of wind tunnel

(Source: China Central Radio and Television, CCTV Military, CCTV-13 "Common Concern", Voice of the Chinese Academy of Sciences, Zhengzhidao, Science Popularization)