Chapter 1175 Forward Detonation Drive

Later in the day.

In a conference room of the Institute of Mechanics of the Chinese Academy of Sciences, an internal meeting of the National Key Laboratory of High Temperature Gas Dynamics is taking place.

Compared with its specifications, the venue layout can be said to be simple and somewhat crude.

Not only was there no decoration, but even the theme of the meeting was projected directly onto a screen with a black text PowerPoint presentation on a white background.

"Hyper-high-speed reproduction wind tunnel and shock wave reflection type forward detonation drive technology system".

It is not difficult to see that this meeting seemed to be held at the last minute.

Generally speaking, academic conferences of this level require some time of preparation in advance, like Chang Haonan did.

Otherwise, even for people in the industry, it would be difficult to remember all the relevant knowledge entirely by relying on their brains.

However, this time, although everyone in the venue remained silent, the atmosphere was not at all dull.

Instead, I felt a little anxious.

After looking around the people at the conference table, Academician Yu Hongru, who was sitting at the top, took a deep breath and finally broke the silence:

"A few days ago, my superior asked me to give a report on the current status of research on hypersonic wind tunnels and hypersonic aircraft."

“Although the chief did not reveal too much information, judging from the recent situation, I think it is very likely that he is preparing to increase investment in our research direction… It has been almost six and a half years since the JF98 wind tunnel passed the acceptance in 10. We have also accumulated certain experience and lessons, so I am going to let everyone discuss the key research directions of the new generation of ultra-high-speed wind tunnels.”

In the past two or three years, as the country's economic situation has gradually improved, rumors about the preparation of a new wind tunnel project have appeared almost every two or three months.

Many people have already become desensitized.

However, Academician Yu Hongru is, after all, a direct disciple of Mr. Guo Yonghuai, and the person in charge of the design of the three generations and four types of high-speed wind tunnels, JF4, JF4A, JF8 and JF10.

Although he has retired to the second line due to his age, his authority is still full as long as he is in charge.

Therefore, when they heard the news from his own mouth, they couldn't help but perk up.

Almost at the same time as Yu Hongru finished speaking, Chen Hong, who was sitting in the first seat on the right, spoke first:

"The success of the JF10 wind tunnel has proved that the technical route proposed by the academician, using Taylor self-similar solution static high-pressure gas as the driving gas source and using the vacuum unloading section to eliminate the high pressure reflected by the detonation wave, is completely feasible. However, from a practical point of view, the test time of the JF10 wind tunnel is still too short to conduct practical hypersonic research such as air-breathing dynamics or flame/plume interaction."

"Therefore, I think the most urgent task is to further improve the experimental time and reproduction accuracy based on the reverse detonation drive method, so that the new generation of wind tunnels can effectively serve the research and development of hypersonic aircraft, which can also be regarded as a phased explanation to the superiors."

After a brief pause, he added:

"In fact, I specifically checked the research path of Academician Chang from the Aviation Power Group and found that he paid great attention to producing tangible results at every stage of long-term research. This increased the confidence of his superiors, and more money was allocated. Finally, a positive cycle was formed, allowing him to go from undergraduate graduation to academician in 10 years..."

Chen Hong's attitude quickly gained the support of many people present.

Starting from the mid-50s, the entire ultra-high-speed wind tunnel project can be said to be quite costly and has also achieved many meaningful results.

However, compared with other research conducted at the same time, the products that can be actually produced and seen are quite limited.

There is no need to mention the two bombs and one satellite.

Even the low-speed and medium-speed wind tunnels next door have made great achievements in the field of aerospace, serving the design and development of many major models.

Although the superiors have never expressed dissatisfaction with this, it is a real pressure for everyone present.

In particular, he gave a very convincing example.

However, Jiang Zonglin, who was sitting on the other side, quickly expressed his opposition:

"The current detonation pressure is limited by the structure and materials of the drive section. The safe initial pressure that can be applied is only 20-50 atm, and the flight Mach number limit that can be reproduced will not exceed 15, without considering the total temperature."

"If we calculate based on the flight conditions, the JF10 can only give a total airflow temperature of 1500-2000K, which is far from enough for research with slightly higher requirements... In this case, if we only solve the problems of experimental time and reproduction accuracy, it will probably be difficult to help the specific projects of CASIC."

To some extent, Jiang Zongli is the successor of Academician Yu Hongru, and he was actually responsible for many specific tasks during the development of the JF10 wind tunnel.

Therefore, even though most people present were tempted by Chen Hong's proposal, he still directly proposed his own plan:

"So I think the focus should continue to be on increasing the total airflow temperature."

"Studies on detonation theory have shown that under the same initial combustible gas pressure conditions, the forward detonation has a driving capacity five times higher than the reverse detonation, and NASA's HYPULSE wind tunnel has proved this. However, the Americans failed to successfully reconstruct the Taylor rarefaction wave into the stable incident shock wave required in the driven section, resulting in severe attenuation of the incident shock wave, and thus were unable to continue in this direction."

At this point, he picked up a printed schematic from in front of him, turned it over and showed it to everyone present, and his aura instantly became sharper:

"But my research group proposed a forward detonation driver based on the shock wave reflection principle two years ago. As long as a shock wave reflection cavity is added to the detonation end of the forward detonation driver, an annular reflection can be generated to generate an upward shock wave of appropriate intensity, compensating for the pressure reduction of the driving airflow caused by the rarefaction wave, thereby improving the stability of the driving airflow."

"Based on current engineering calculations, this technology can achieve a Mach number acceleration ratio of up to 3.6. If this is still not enough, then an auxiliary detonation section of hydrogen/oxygen mixture can be added behind the shock wave reflection cavity to further reduce the attenuation of the rarefaction wave by changing the zero-velocity boundary condition of the Taylor self-similar solution."

Obviously, in Jiang Zonglin's view, the failure of the Americans does not mean anything. He has already found a way to surpass the Americans in this field.

In fact, due to the long-term problem of attenuation of the incident shock wave of the forward detonation, NASA has even begun to try to replace some wind tunnel tests with numerical calculations.

After finishing his statement, perhaps in response to Chen Hong's example, he continued in a somewhat tit-for-tat manner:

"Academician Chang is indeed good at impressing his superiors with solid project results at every stage of long-term research, but it should also be noted that almost all of his products have directly or indirectly promoted the leapfrog progress of my country's aviation industry, rather than patching up the old foundation."

"Let's not dwell on how he did it, but it's clear that if our new wind tunnel only increases the terminal velocity of the missile from three times the speed of sound to four times the speed of sound, it would be difficult to achieve the same effect as Academician Chang..."

This speech was well-reasoned and the key was that it came with a solution while raising the problem, so the situation soon turned around.

Chen Hong naturally couldn't just give up like that:

"The shock wave reflection solution you proposed, Lao Jiang, is indeed feasible in principle. However, both the Mach number acceleration ratio of 3.6 and the calculation parameters currently obtained are obtained through computational simulation. However, the calculation model of hypersonic speed, including the hydrogen-oxygen detonation process itself, is not mature enough. It is too radical to directly implement a large-scale project like this!"

"..."

Gradually, the debate entered a white-hot stage.

However, just as the air began to fill with gunpowder, there was a sudden knock on the door outside the meeting room.

A staff member walked in quickly and whispered a few words to Academician Yu Hongru.

The latter's expression changed slightly, and after a long pause he looked at everyone again:

"You were just talking about Academician Chang Haonan..."

There was a hint of joking in his tone:

"Now Academician Chang...will be here soon."