China Aerospace News reporter learned from the 31th Institute of the Third Academy of Aerospace Science and Industry of China that the pre-cooling device of the combined power engine developed by the institute - the Yunlong engine has completed the temperature drop test of the largest scale and maximum air flow in China, and the test results have exceeded expectations.
As early as 2018, the heads of the three hospitals publicly stated to the media that China is developing a "space aircraft" that can be reused for round-trip transportation between heaven and earth. According to the plan, the "Yunlong" engine will provide power for the air-space round-trip aircraft.
The reporter learned that last year, 31 completed the trial production of the prototype of the engine principle and passed the first phase of system-level ground test verification. A number of key technologies of this type of engine have made breakthroughs.
A new type of power for round-trip flight in space and air
The Yunlong engine is a new type of power for the space shuttle that 31 is exploring. If successful, it can boost the aircraft to take off horizontally from the ground like an airplane and then land horizontally to the ground, enabling reusable round-trip transportation between space and air. But it would fly faster and higher than an airplane, and it would be different from the vertical take-off and landing launch vehicles that are common today.
How do I send a spacecraft into space? The most mainstream way to do this is to use launch vehicles. However, the rocket engine starts from ground ignition, and all the power sources required need to be "self-sufficient", relying on igniting the oxidant and fuel that comes with it to generate thrust. According to public data, the rocket needs to carry a large amount of oxidant when flying, and the mass of the propellant accounts for more than 85% of the mass of the entire arrow, so that the mass space of the rocket to the "passenger" - payload is greatly compressed.
To this end, the researchers proposed a reusable spacecraft power system scheme that uses suction mode during the climb phase in the atmosphere. Such schemes use oxygen from the air as an oxidant, which will effectively reduce the consumption of propellant and the quality of the propellant that needs to be carried.
But in fact, the existing engines of mankind are divided into turbines, turbofans, rams, rockets and other kinds, each of which has its own working range and advantages, and it is difficult to achieve wide-speed domain large airspace space round-trip transportation by relying on one alone, so the combination of different engines can complete a higher mission. Finding the ideal combined power has become the most urgent task in the field of aerospace flight at home and abroad, among which the direction of pre-cooling power has received more and more attention and research, and gradually constitutes a new solution for air-space transportation power.
Ma Tongling, chief engineer of "Yunlong" engine technology, introduced that one of the biggest difficulties is how to achieve high performance under air intake conditions of nearly 1000 °C or even higher. When the spacecraft flies at ultra-high speed in the atmosphere for a long time, the airflow temperature rises sharply, which makes the material unbearable and high-performance components such as the compressor level cannot work. To solve this problem, can not only rely on the material limit of the lifting, the most direct way is to cool, pre-cooling power technology is to introduce the intake of active cooling technology, and a variety of dynamic thermal cycle advantages for deep integration, resulting in a more advantageous new thermal cycle program.
Extremely demanding! Cool down to 1000 °C in 0.01 seconds
Since the "Twelfth Five-Year Plan", pre-cooling power technology has entered the vision of 31 experts. At that time, such technologies had been carried out in the world for many years of basic research, and made certain breakthroughs, and 31 teams were shocked by the complexity of the technology after the initial follow-up study: to achieve 1000 °C cooling in 0.01 seconds, operating in minus 150 °C environment requires frost-free... Extremely demanding!
But at the same time, the charm of technological innovation deeply attracts this group of astronauts - if the technology is successfully broken, new types of power will become possible, bringing about subversive changes in the way space transportation is carried out.
After some consideration, 31 decided to do it. With what kind of input? Is it just a new type of technology research, or is it used as a reserve power to gather wisdom to tackle key problems? After much deliberation, the leadership and the group of experts of 31 institutes chose the latter.
In June 2018, the pre-cooling power technology center with the core mission of pre-cooling power research and development was officially established in 31. Pre-cooling power technology is still in its infancy, and foreign countries are slightly ahead, but no breakthrough has been made in engineering applications, so it has not yet opened up too much gap. As the general unit of the new engine, the 31 pre-cooling power technology centers must compete with international experts on the same stage, and also try their best to catch up.
The problems ahead should not be underestimated. The precooler used to cool the high-temperature flow is one of the core technologies of the precooled engine. As heat exchange devices, precoolers can be found everywhere in everyday engineering applications, but it is not feasible to use traditional heat exchanger technology directly for aerospace vehicles. Leaving aside the fact that the volume and weight of the traditional heat exchanger are too large, in terms of thermal response time, compared with the traditional combustion chamber, the heat exchanger is a "chronic sub", and the aircraft with extremely high requirements for response time is obviously an "acute sub", and the chronic sub is used as an acute sub, and the control problem comes. In addition, it also faces the challenges of materials, processes, control, reliability and so on.
"The two core technologies determine whether the technical solution is established, and several key technologies determine whether the engineering application can be realized." Ma Tongling said. If you want to succeed, you must take them down one by one, and you must take the road of independent innovation.
A number of key technologies have been conquered
I hope that the "Cloud Dragon" will take off
As a domestic aviation engine "professional household", 31 after more than 60 years of precipitation and accumulation, the engine type is very complete, both turbines, turbofans, ramjet engines, as well as solid rocket engines, and a large number of products delivered to users, which provides a natural advantage for different engines to achieve power combinations, but also allows the team to carry out new technology research has the confidence.
The main force of the pre-cooling power technology center is a group of "newborn calves", whose average age is less than 30 years old, and there are both overseas students and domestic high-caliber students. The team and domestic universities work together to tackle key problems, and gradually form an open and inclusive integrated R&D platform with 31 as the overall core, covering technical research, product design, processing and manufacturing, experimental testing, and industrialization promotion.
At present, 31 institutes have killed many roadblocks. Niu Jun, director of the Institute's Precooling Power Technology Center, introduced that at present, the "Yunlong" engine has completed the design and manufacturing technology of large-scale deep precoolers and micro-channel high and low temperature heat exchangers, and the key technologies such as the new helium turbine system and helium compression system have made breakthroughs.
"Pre-cooling power technology is one of the ideal power of the new air-space round-trip aircraft, which is more and more valued at home and abroad, and it is hoped that 31 'Yunlong' engines will be available as soon as possible, at that time, the field of air-space transportation will usher in more possibilities." Niu Jun said.
"Yunlong" is the Chinese name given by the team to the precooled engine, "ICE" is its English name, which is the English Incorporated multicycle Cooling Engine abbreviation of "multi-cycle deep coupling precooled engine". The team loves it, cherishes it, and hopes that it will break through the clouds as soon as possible and truly become a "dragon in the clouds".
Text/China Aerospace News reporter Zhao Cong correspondent Zhang Zhigang Xu Yang
Photo: China Aerospace News reporter Su Dong
Editor/Zhao Cong
Audit/Chen Li
Producer/Soadi
Source: China Aerospace News