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Chinese team says hypersonic engine can hit Mach 9 on low-cost jet fuel, ground experiments successful

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Chinese team says hypersonic engine can hit Mach 9 on low-cost jet fuel, ground experiments successful​

  • The device travel at nine times the speed of sound without the expense or explosion risk of burning hydrogen, according to paper
  • Researchers in China say ground experiments at Beijing’s JF-12 shock tunnel were successful


Published: 8:00pm, 18 Nov, 2022

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The Chinese government plans to build a fleet of hypersonic aircraft that can transport passengers anywhere on the planet in an hour or two. Photo: SCMP

Researchers in China say they have developed the world’s first hypersonic detonation wave engine capable of powering flight at nine times the speed of sound using low-cost jet fuel.

Several successful ground experiments for the oblique detonation engine, which generates thrust through a burst of explosions, were carried out at the JF-12 hypersonic shock tunnel in Beijing earlier this year, according to the researchers.

The team led by Liu Yunfeng, a senior engineer with the Institute of Mechanics, Chinese Academy of Sciences, revealed technical details of the kerosene-powered engine in a paper published in the peer-reviewed Journal of Experiments in Fluid Mechanics on November 11.

“No test results for [hypersonic detonation engines using] aviation kerosene have been made public before,” they wrote.

A detonation engine can run more efficiently and powerfully than other hypersonic engines such as the scramjet. The detonation wave triggers a series of explosions, which happen almost instantly and release considerably more energy than conventional combustion does with the same amount of fuel, especially at speeds over Mach 8.

Scientists around the world have built detonation engines, but they mostly use hydrogen as fuel, which comes with a high price tag and risk of explosions.
Liu’s engine uses RP-3, a jet fuel commonly found in Chinese airports.

“Aviation kerosene is the fuel of choice for air-breathing engines due to its high energy density and ease of storage and transport,” he said.

The idea of using jet fuel to power hypersonic flight has been around for decades, but the difficulty of igniting the kerosene in extremely hot and fast air has posed a challenge for scientists.

“It is not easy to detonate,” Liu said.

Kerosene burns more slowly than hydrogen, so kerosene-powered engines typically require a longer detonation chamber to retain the fuel-air mixture for a longer period of time.

Computer models estimated that the detonation chamber of a kerosene-fuelled engine would need to be 10 times longer than one that uses hydrogen.
The extra length would be impossible for most hypersonic planes, where every millimetre counts, according to the team.

But the Chinese scientists found that a simple modification – adding a thumbnail-size bump to the surface of the engine’s air inlet – could make the ignition of kerosene easier while keeping the chamber’s size small.

When fresh air arrives at the narrow mouth of the engine’s wedge-shaped inlet, fast-moving air molecules are compressed and heated.
The hot air then mixes with tiny droplets of kerosene, which break apart to form even smaller molecules.

As the mixture of air and fuel hits the bump on the otherwise smooth surface of the inlet, shock waves are produced.

The results of the test run, conducted under various conditions in the JF-12 tunnel, suggest that these bump-induced shock waves could not only ignite the kerosene but help confine the explosions to a small space, generating a steady supply of thrust.

China has developed several hypersonic missiles, including the DF-17 and YJ-21, capable of hitting a building or moving warship fast enough to evade most air defence systems.

The Chinese government plans to find civilian applications for hypersonic technology by building a fleet of aircraft that can transport passengers anywhere on the planet within an hour or two.
Meanwhile, defence contractor Lockheed Martin plans to conduct the first flight of the SR-72, an unmanned hypersonic spy plane known as “Son of Blackbird”, by 2025.

Hypersonic aircraft must be capabale of making routine long-distance flights under extreme conditions. Reducing construction and operational costs remains a major challenge, according to scientists and engineers involved in developing the technology.

 
Ahh this SCMP article is on the oblique detonation engine which operates using different principles compared to the Tsinghua test flight of the rotating detonation engine.

US has long played with pulse detonation but everyone understands rotating detonation is the successor of pulse detonation which the US is trying to do as well. Tsinghua University flew the world's first rotating detonation engine though. That is, outside of PLA which are all not given details. I think PLA have much more advanced hypersonic craft engines than the Tsinghua test platform and at least some of the PLA projects would be the oblique detonation type for HGV or hypersonic non gliding missiles and unmanned hypersonic craft. For actual manned craft, the only proper way is combined cycle which China has flown too. World's first combined cycle of rocket and scramjet is the Northwestern Polytechnical University's Feitian 1 project.

Again just another public project with a University. RBCC engine with rocket + ramjet + scramjet powered using a Kerosene fuel.

https://www.guancha.cn/politics/2022_07_05_647948.shtml

" 国际首次验证了煤油燃料火箭冲压组合循环发动机火箭/亚燃、亚燃、超燃、火箭/超燃的多模态平稳过渡和宽域综合能力"

First demonstration in the world of Rocket to ramjet, ramjet or scramjet transition, and rocket + scramjet different modes.


Another test during that week from an undisclosed organization (could be government based or military) used a different vehicle to test a TRCC combined cycle engine.

Commonly confused with this uni project. The Tsinghua one just looks at RDE which is technically a grail propulsion system but not as exciting as combined cycles since combined cycles can actually be used for larger craft.

TRCC engine is for a large craft and speculated to be for China's Tengyun project or another single or two stage to orbit craft project.

The TRCC engine in ground testing.

2021 Zhuhai TengYun Project TRCC TSCC combined cycle engine test.jpg


The hints on long range HGV weapons of China were powered by sodramjet or oblique detonation engines. Which the leaks mentioned were first theorized by NASA scientists but they never made any prototypes even and could not figure out how to build one.

These were the 2017 to 2020 HGV related leaks and talks of weapon type craft or delivery systems. Then the conversations and reports were focused onto the Tengyun aircraft and SSTO or TSTO vehicles rather than weapons. This was around the time China performed the mach 20 (average speed) test flight circumnavigating globe.
 

China claims ‘world’s first’ kerosene-powered engine could propel jets nine times the speed of sound​

The hypersonic detonation wave engine was tested earlier this year.

Baba Tamim
Nov 20, 2022 11:21 AM EST

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Representational image: A distinctive vapor cone forms around the jet as it nears the speed of sound.
skinman/iStock

Chinese researchers claim to have created the "world's first" hypersonic detonation wave engine, which can propel a plane at Mach 9, nine times the speed of sound, using inexpensive jet fuel.

The oblique detonation engine underwent a number of successful ground tests at Beijing's JF-12 hypersonic shock tunnel, the South China Morning Post (SCMP) reported on Friday.

"No test results for [hypersonic detonation engines using] aviation kerosene have been made public before," said the researchers.

The researchers released technical information on the kerosene-powered engine in a report published in the peer-reviewed Journal of Experiments in Fluid Mechanics on November 11. The tests were carried out earlier this year, noted SCMP.

The team experimenting with the engine, which generates thrust by a burst of explosions, was led by Liu Yunfeng, a senior engineer at the Institute of Mechanics, Chinese Academy of Sciences.

Aviation Kerosene-powered detonation engine​

Compared to other hypersonic engines like the scramjet, a detonation engine can operate more effectively and with greater power.

A succession of explosions are set off by the detonation wave. These explosions occur almost rapidly and release a lot more energy than traditional combustion does with the same amount of fuel, especially at speeds beyond Mach 8.

Detonation engines have been developed by scientists all around the world; however, they typically use hydrogen fuel, which is expensive and explosive.

Jet fuel, known as RP-3, which is frequently found in Chinese airports, powers Yunfeng's engine.

Due to its high energy density and simplicity of storage and transportation, "Aviation kerosene is the fuel of choice for air-breathing engines," Yunfeng claimed.

Although the concept of using jet fuel to propel hypersonic flight has been around for years, "It is not easy to detonate," said Yunfeng.

Scientists have had problems because it is difficult to ignite the kerosene in hot, moving air.

According to computer simulations, an engine powered by kerosene would require a detonation chamber that was ten times longer than an engine powered by hydrogen.

The additional length would be impractical for the majority of hypersonic aircraft since each millimeter matters, as per the team.

The Chinese researchers, however, discovered that a straightforward modification—adding a thumbnail-sized bump to the engine's air inlet surface—could facilitate kerosene ignition while maintaining a compact chamber.

The goal​

The DF-17 and YJ-21 are two hypersonic missiles that China has developed that can strike a structure or a vessel that is moving while avoiding the majority of air defense systems.

By developing a fleet of planes that can deliver passengers anywhere on the globe in only a few hours, the Chinese government hopes to discover uses for hypersonic technology in the civil sector.

Regular long-distance flights under challenging circumstances must be possible for hypersonic aircraft.

However, scientists and engineers working on the technology say that lowering construction and operating costs is still a significant problem.

 

China Might Have Built a Mach 9 Kerosene-Powered Hypersonic Engine​

Ryan Erik King
Tue, November 22, 2022 at 7:00 AM

Researchers in China claim to have developed a hypersonic engine capable of propelling a plane up to speeds of Mach 9, nine times the speed of sound. Interesting Engineering reported that Liu Yunfeng, a senior Chinese Academy of Sciences engineer, led the team that created the unique detonation wave engine. The engine generates thrust via detonating kerosene in a series of explosions instead of continually like combustion engines. Earlier this month, technical information on the kerosene-powered engine was published in the peer-reviewed Journal of Experiments in Fluid Mechanics.

Besides the absurdly-high claimed speeds, the engine’s use of kerosene-based jet fuel has gotten the attention of many. The Chinese-designed hypersonic engine runs on RP-3 jet fuel. According to Shell, RP-3 is Chinese export-grade aviation fuel, equivalent to Jet A-1, used by commercial airliners in the United States. Despite being difficult to detonate, Yunfeng believes that aviation kerosene is ideal for all air-breathing engines because of its energy density and ease of storage and transportation.

The hypersonic detonation wave engine successfully underwent ground tests in Beijing. While hypersonic propulsion has primarily been used for military purposes, several ventures on both sides of the Pacific Ocean foresee its use on commercial aircraft. Houston-based Venus Aerospace hopes its hypersonic plane will transport passengers from Tokyo to Los Angeles in an hour. However, there are many financial and logistical hurdles in the way of transoceanic flights measured in minutes instead of hours.

 
I think the SSTO and TSTO projects are much more interesting because they are transmedium endo and exo atmosphere and hypersonic too.

The Shenlong vehicle and Yunlong engine being made by CASIC are yet another propulsion type for long range, endurance, and high speed combining different engines.

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These are ground tests of Yunlong engine for one type of SSTO vehicle. But back in 2018, CASIC team flew another platform, a secretive vehicle which uses a combined cycle engine. Flew already, back in 2018. It's the first in the world and by far ahead of the USA in making a combined cycle and not only that but flying a combined cycle vehicle... more than 4 years ago.


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CASIC itself did admit and reveal that this flight took many world firsts. Since 2021, China also flew a round the world mach 20 (calculated average speed based on distance traveled/time) hypersonic craft which the US made some fuss about for a while but then their supa people dismiss it all. Good.

Point it China has more hypersonic craft and weapons than the US intelligence can count. Hundreds of flights, hundreds of times more flights than the US. Scramjet powered ones, combined cycle TRCC and RBCC ones, oblique detonation, rotating detonation. A new kerosene powered craft or missile is yet just another in China's tree of hypersonic programs, aircraft, and weapons.
 
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Now DF-27 (DF-17's successor platform) is reportedly reaching service. A longer ranged hypersonic weapon maybe employinig HGV style control similar to DF-17's DF-ZF.

The Tsinghua University's rotating detonation engine is nothing compared to high secrecy state programs they only make announcements of tests for and once in a while the organizations performing the work will leak a few slides of stuff that they deem not sensitive anymore or known by the US intelligence gathering efforts.

Other research institute's new engines and test flights are also seemingly much less impressive than the state and military programs which seem far ahead. Allowing public research universities and institutes like China Academy of Sciences and affiliated universities to play with technologies that the military and government space branches have already put into service so that some talents can perhaps improve on the work done by the big dogs by walking the path again after. Meanwhile the big dogs are onto newer crazier technologies at the bleeding edge while the more public research organizations begin playing with those engines. USA can barely fly a scramjet still. Certainly not for as far or as long. No combined cycle for the US either except in their Top Gun movie. They do seem to be much ahead on variable cycle turbofan engine though with US ADVENT program.
 
By the Tsinghua engine program I mean this one.

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The new kerosene based combined cycle engine may be simply a state program equivalent of this university level project which made a combined cycle engine that runs on a kerosene based fuel. Notice it is partly financed by CASIC.

Northwestern Polytechnical University just completed a test of their Feitian-1 kerosene RBCC e...jpg



This one flew with another that isn't photographed for public which both the US observed back when both flew in the same week in July 2022.

All the low level and low sensitivity projects such as these do make it to reporting and sometimes photographed in a handful of angles. The state run department projects are the real champions though and already made use of various types of reaction engines.

Now the only grail engine outside RDE, ODE, TRCC and RBCC (flown, flown, flown, flown) are the variable cycle turbofan and of course ahahaha ... anti-gravity. Scramjet is old, boring, and long ago, easy. None of the western fanboys ever admit to anyone else being able to make something and progress and ignored when China could fly scramjets since the 2000s and had breakthroughs to allow for scramjet combined cycles. We've been openly researching scramjet since the 1970s. Indians still can barely keep their scramjet lit for more than a few dozen seconds and all that just in ground testing. I guess those supercomputers and hypersonic wind tunnels are useful. The Israeli hypersonic tunnel the Indians use just don't cut it.

Guess maybe the Russians have those anti gravity stuff if they keep buzzing US carrier groups with their hyper Russian physics anti gravity craft that look like tic tac candy :P jk jk
 
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