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 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 curtain 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 our research direction... It has happened that almost six years have passed since the JF10 wind tunnel passed the acceptance test in 1998. Over the past year and a half, we have accumulated a certain amount of experience and lessons, so I am going to let you 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. Only by forming a positive cycle can he 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 products that can actually 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 20~50atm, and the reproducible flight Mach number limit will not exceed the level of 15, without considering the total temperature. ”


    "If calculated according to the reproduction of flight conditions, then 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 experiment is solved The issues of time and reproduction accuracy may not 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."


    "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 proven this, 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 serious attenuation of the incident shock wave and prevented them from continuing in this direction. "


    Having said 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 became sharper:


    "But my research group has proposed a forward detonation driver that applies the principle of shock wave reflection as early as two years ago. As long as a shock wave reflection cavity is added to the detonation end of the forward detonation driver, it can Produce annular reflection and 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 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 Americans in this field -


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


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


    “Academician Chang is indeed good at impressing superior leaders with tangible project results at every stage of long-term research, but it should also be noted that almost all the products he has produced have directly or indirectly promoted the leapfrog development of my country’s aviation industry. Progress, rather than tinkering with the old foundation.”


    "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 same effect as an academician..."


    This speech was well-founded, and the key was that it raised questions while also providing solutions, so the situation quickly reversed.


    Of course, Chen Hong couldn''t just give up:


    "Lao Jiang, the shock wave reflection scheme you proposed is indeed feasible in principle, but both the Mach number acceleration ratio of 3.6 and the calculation parameters obtained so far are obtained through computational simulation, but hypersonic speeds, including hydrogen-oxygen explosion The calculation model of the bombardment process itself is not mature enough, so it is too radical to just start a large-scale project like this!”


    “…”


    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 something next to Academician Yu Hongru.


    The latter''s face changed slightly, and he paused for a while before looking at the crowd again:


    "You were all making fun of Academician Chang Haonan just now..."


    There was a hint of joking in his tone:


    "Academician Chang...is coming soon."


    (End of chapter)