Chapter 1175 Forward Detonation Drive
Later that 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 is there no decoration, even the theme of the meeting is directly projected on a curtain with a PPT with black text 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 a temporary meeting.
Generally speaking, academic conferences of this level require preparation for a period of time in advance like Chang Haonan did.
Otherwise, even people in the industry would find it difficult to remember all the relevant knowledge entirely in 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, the superior leaders He asked me to make a report, and the topic was about the current research status of hyper-speed wind tunnels and hypersonic aircraft."
"Although the chief did not disclose much information, judging from the recent situation, I think it is very important. Maybe we are preparing to increase investment in this research direction of ours... It has happened that almost six and a half years have passed since the JF10 wind tunnel passed the acceptance test in 1998. We have also accumulated certain experience and lessons, so I am ready to let Let’s 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. will appear once.
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 at the same time as Yu Hongru’s words fell, 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 JF10 wind tunnel is still too short, no It is impossible to conduct practical research on hypersonic topics such as air-breathing power or flame/plume interaction.”
“So I think the top priority is to further develop the reverse detonation drive method. Improve the experimental time and reproduction accuracy, so that the new generation of wind tunnel can effectively serve the superb The research and development of sonic aircraft can be regarded as a staged explanation to the superiors."
After a slight pause, he added:
"Actually, I specifically checked. After going through the research route of Academician Chang from the Aviation Power Group, I found that he pays great attention to long-term development. At each stage of the research, tangible results are produced, which increases the confidence of the superiors and allocates more money. Finally, a positive cycle is 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.
However, compared with other research carried out at the same time, the actual products that can be touched and seen are quite limited——
Two bombs and one satellite are not necessary. carry.
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 applicable safe starting pressure is only 20~50atm, which can be reproduced. The flight Mach number limit will not exceed the level of 15, without considering the total temperature."
"If calculated based on the recurrence of flight conditions, then the JF10 can only give The total air flow temperature of 1500-2000K is far from enough for research with slightly higher requirements... In this case, it is difficult to solve the problems of experimental time and reproduction accuracy. Specific projects on the science and engineering side have helped.”
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 of the people present were interested in 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. ”
“Research on detonation theory shows that under the same initial pressure conditions of combustible gas, forward detonation has a driving capacity five times higher than reverse detonation, and NASA’s HYPULSE wind tunnel has already This was proved, but the Americans failed to successfully reconstruct the Taylor rarefaction wave into the required smooth incident shock wave in the driven section, which resulted in the serious attenuation of the incident shock wave and prevented them from continuing in this direction."
Speaking of this, he picked up a schematic diagram that had been printed in front of him, turned it over and showed it to everyone present, and his whole aura suddenly sharpened:
"But my As early as two years ago, the research team proposed a forward detonation driver that applies the principle of shock wave reflection. As long as a shock wave reflection cavity is added to the detonation end of the forward detonation driver, annular reflection can be produced. , generate an upward shock wave of appropriate intensity 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 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. By changing the Taylor The zero-velocity boundary condition of the self-similar solution further reduces the attenuation of sparse waves.”
Obviously, in Jiang Zonglin’s view, the failure of the Americans does not mean anything. He has already found a way to surpass the United States in this field. Human method——
In fact, due to the long-term problem of shock wave attenuation of forward detonation incident, 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 just now, he also continued somewhat tit-for-tat:
“Academician Chang is really good at every stage of long-term research. Impress your superiors with real project results, but you should also note that almost all the products he comes up with have directly or indirectly promoted the leap-forward progress of our country's aviation industry, rather than patching things up on the old basis. .”
"Let's not dwell on 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 achieve the same results as usual. The effect is the same as that of an academician..."
This speech was well-founded. The key was that while raising the problem, it also came with a solution, so the situation quickly reversed.
Of course it is impossible for Chen Hong to give up just like that:
“The shock wave reflection scheme proposed by Lao Jiang is indeed feasible in principle, but whether it is the Mach number acceleration ratio of 3.6 or the current The calculation parameters are all obtained through calculation and simulation, but the calculation model of hypersonic speed, including the hydrogen-oxygen detonation process itself, is not mature enough. It is too radical to directly apply it to large-scale projects..."
"..."
Gradually, the debate entered a heated stage.
However, just when the smell of gunpowder began to fill the air, there was a sudden knock on the door outside the conference room.
A staff member walked in quickly and whispered a few words next to Academician Yu Hongru.
The latter's face changed slightly, and he paused for a long time before looking at everyone again:
"You were all making fun of Academician Chang Haonan just now..."
There was a hint of joking in his tone:
"Now Academician Chang... is coming soon."
(End of this chapter)