The military-industrial scientific research system of the academic master

Later in the day.

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

Compared with its specifications, the layout of the venue can be said to be simple to a bit crude.

Not only was there no decoration, even the theme of the meeting was directly projected on a screen with a PPT with black characters on a white background——

"Ultra-high speed reappearance wind tunnel and shock wave reflection forward detonation drive technology system".

It is not difficult to see that this meeting was more like an impromptu meeting.

Generally speaking, academic meetings of this level require preparations like Chang Haonan's for a period of time in advance.

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

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

Instead, he was a little anxious.

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

"A few days ago, my superiors asked me to make a report. The topic was about the current research status of ultra-high-speed wind tunnels and hypersonic aircraft."

"Although the chief did not disclose much information, judging from the recent situation, I think it is very likely that he is preparing to increase investment in this research direction of ours... It happened to be almost the same time since the JF10 wind tunnel passed the acceptance test in 1998. Over the past six and a half years, we have accumulated a certain amount of experience and lessons, so I am going to let everyone discuss the key research directions for 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 new wind tunnel projects 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 third generation four-type high-speed wind tunnel of JF4, JF4A, JF8 and JF10.

Although now he has been relegated to the second line due to his age, as long as he comes out and takes charge, his authority is still full.

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

Almost as soon as Yu Hongru finished speaking, Chen Hong, who was sitting in the first place on the right, spoke first:

"The success of the JF10 wind tunnel has proven that the technical route proposed by the academician, using Taylor's self-similar solution of static high-pressure gas as the driving gas source, and using the vacuum detonation section to eliminate the high pressure reflected by the detonation wave is completely feasible, but 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 aspiration power or flame/plume interaction.”

"Therefore, I believe that the top priority is to further improve the experimental time and reproduction accuracy based on the reverse detonation drive method, so that the new generation of wind tunnel can effectively serve the research and development of hypersonic aircraft, which can also be regarded as a step for superiors. "

After a slight pause, he added:

"In fact, I specifically checked the research route of Academician Chang from the Aerospace Power Group, and found that he attaches great importance to producing tangible results at every stage of long-term research. This increases the confidence of superior leaders and allocates money. That’s a lot, and finally a positive cycle will be formed, allowing him to graduate from undergraduate to academician in 10 years..."

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

Starting from the mid-1950s, the entire ultra-high-speed wind tunnel project can be said to have cost a lot of money and achieved many meaningful results.

But compared to other research carried out at the same time, the actual products that can be touched and seen are quite limited——

There is no need to mention two bombs and one star.

Even the low-speed and medium-speed wind tunnels next door are also shining in the aerospace field, serving the design and development of many major models.

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

In particular, he gave a quite 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 reproducible flight Mach number limit will not exceed the level of 15, regardless of the total temperature. Down."

"If calculated based on the reproduction of 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, only the solution The problems of experimental time and reproducibility may hardly help the specific projects of Aerospace Science and Industry.”

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

Therefore, even though most people present were moved by Chen Hong's proposal, he still put forward his own plan:

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

"Studies on detonation theory show that under the same initial pressure of combustible gas, forward detonation has a driving capacity five times higher than reverse detonation, and NASA's HYPULSE wind tunnel has proved this. However, the Americans failed to successfully reconstruct the Taylor rarefaction wave into the steady incident shock wave required in the driven section, resulting in severe attenuation of the incident shock wave, which prevented it from continuing in this direction."

At this point, he picked up a long-printed schematic diagram in front of him, turned it over and showed it to everyone present, and his momentum instantly became sharp:

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

"Judging from the current engineering calculations, this technology can achieve a Mach number acceleration ratio of up to 3.6. If it is still not enough, then a hydrogen/oxygen mixed auxiliary detonation section can be added behind the shock wave reflection cavity to further reduce the attenuation of the rarefaction wave by changing the zero-speed 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 the attenuation of the incident shock wave of the forward detonation, NASA has even begun to try to replace part of the wind tunnel test with numerical calculations.

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

"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 get entangled in how he did it, but it is obvious that if our new wind tunnel only increases the terminal speed of the missile from three times the speed of sound to four times the speed of sound, it will probably be difficult to get the same effect as Academician Chang..."

This speech is well-reasoned, and the key is that while raising the problem, it also comes with a solution, so it quickly reverses the situation.

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

"The shock wave reflection scheme you proposed, Lao Jiang, is indeed feasible in principle, but both the Mach number acceleration ratio of 3.6 and the current calculation parameters are obtained through computational simulation, but the calculation model of hypersonic speed, including the hydrogen-oxygen detonation process itself, is not mature enough. It's too radical to just go straight to a large project like this!"

"..."

Gradually, the debate entered a white-hot stage.

However, just when the air was already filled with gunpowder, there was a sudden knock on the door outside the conference room.

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

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

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

There was a hint of joking in his tone:

"Now Academician Chang... is coming soon."