Chapter 18 The idea of hypersonics
"Xiao Chang, Xiao... Professor Liu told me that you had a very deep and clear understanding of this design during the defense. To be honest, I had so many I don’t believe it at all, but now I have seen it.”
Du Yishan cheerfully picked up the design plan of Chang Haonan and others on the table: “It’s like the waves behind the Yangtze River push the waves ahead. My old bones are almost going to die. I can’t keep up with the ideas of you young people.”
“Academician Du was so impressed. I just used some simulation methods to make an improved model design. There are still many things that need to be like yours. Learn from your predecessors.”
Chang Haonan is not a random compliment. In fact, Du Yishan still plays a vital role in the aviation industry until the new century, and played an important role in the development of a certain type of transport aircraft. .
"Ha, it sounds nice to talk." Du Yishan has obviously read this design report many times, and he immediately turned to the content about the performance test: "What do you think is the biggest advantage of the mandibular air intake designed by you? What? In other words, is there any other place besides being on this plane?"
This question shocked Chang Haonan, and he secretly sighed that Academician Du's vision was really good, but Spending at most two or three hours looking at the design description revealed the greater potential of this design.
“In fact, we have discovered in simulations that the new air inlet has more obvious advantages at higher speeds than the traditional design. Although the maximum speed of the improved J-7 can only reach Mach 2.0, However, we still conducted some calculations on the flow field distribution and performance at higher speeds. The results show that this inlet design can maintain 0.73 up to the speed of Mach 3.5-4.0 and the inflow angle of attack of 6°. The total pressure recovery coefficient is above, and if the high speed is specially optimized in the design point selection, the performance can be even higher."
"Can it reach Mach 4?"
Du Yishan used to rely on it. He made a qualitative judgment based on experience, but after all, his eyes were not in a wind tunnel, so he still couldn't see the specific data.
"Well... we have calculated up to Mach 4. At higher speeds, the current calculation and simulation methods are not suitable. We need to improve the method, and we need better equipment."
In other words, Chang Haonan means that this design still has potential to be tapped, but it cannot be tapped due to current conditions.
“As for the use, I think in the short term, we can consider combining it with a liquid fuel ramjet engine and using it on missiles with a speed of Mach 3-4. In the long term, if we need to develop and use it in the future For scramjet engines and air-breathing hypersonic aircraft that can fly at a speed of more than 5 times the speed of sound, this design idea should also be useful as a preliminary study. "
This time, Du Yishan's eyes were filled with excitement. I was a little shocked.
In 1996, China had not even fully developed a subsonic cruise missile using a turbojet engine.
Under this circumstance, this junior undergraduate student has actually begun to consider making technical preparations for supersonic cruise missiles and even hypersonic cruise missiles.
Although it is not that no one is doing preliminary research in this area, they are basically still in feasibility analysis or theoretical research.
And this air inlet design, and more importantly, this integrated design idea, can even be counted as part of engineering practice.
It is a pity that with the current strength of China's aviation industry, there is no way to carry out more in-depth system development work.
Looking at the expression of Academician Du Yishan in front of him, Chang Haonan knew that he should be stable.
Sure enough, after about a minute of ideological struggle, Du Yishan put the design instructions in his hand back on the table next to him, raised his head and asked Chang Haonan:
"Xiao Chang, I don't know what you think about it. What are your plans for the future? "
Not far away, Professor Liu Hongbo closed his eyes in pain - his last hope was shattered.
As a student of Du Yishan, he knew very well that what he just said was a standard question before an academician prepares to recruit disciples.
Faced with this problem, Chang Haonan almost did not think twice: "Since I have chosen Beijing Airlines' aircraft system, it is natural for me to continue my studies and use scientific research results to help the development of our country's aviation industry!" He had no systematic approach to this path in his previous life. The situation has been overcome, and it is even more impossible to change my mind now.
"Well... your course design, with a slight modification, can be used as a graduation project. I can be your graduation project tutor." Du Yishan nodded: "As for the future, I have two suggestions here. I wonder if you are interested in listening to them?”
Although this is a question, if someone really answers that they are not interested, they would be stupid.
"Of course, please speak, Academician Du."
Chang Haonan took a deep breath and tried to calm down his excitement.
"First, I can make an exception for you to apply for a place to study abroad on a government-sponsored basis. It may be in the UK or the United States. If you are willing to take this path, then in your senior year, focus on overcoming the language barrier. This way You can adapt to the environment as soon as possible after that.”
Halfway through Du Yishan’s proposal, Liu Hongbo on the other side wanted to get up, looking like he was hesitant to speak.
Although government-sponsored students studying abroad must return to their country to work according to regulations, in this era, there are quite a few people who never return after going out, and most of them do not actually have the intention of breaking the contract at the beginning. But after arriving abroad and seeing better living, working and even scientific research conditions, I finally chose to stay outside.
Although publicly-sponsored international students who refuse to return to their country need to repay all state-funded expenses in accordance with the agreement and pay an additional 30% liquidated damages, with the current income gap between domestic and foreign countries, this money is not enough for those who stay and work in European and American countries. It's nothing to humans.
Therefore, Liu Hongbo's philosophy has always been that if the students themselves have the idea of going abroad, he will not object, but if the students do not have the intention, he will not take the initiative to mention it.
He was really afraid that the good prospect he had fallen in love with would never come back.
Especially for a genius like Chang Haonan, who can be said to be one in a million. If he goes abroad, he will definitely be the target of the other country. Even if he wants to come back, it may not be that easy.
"Second, this is also an exception. You can choose to join my research group and skip the master's level and study directly for a doctorate. Compared with going abroad, you can be exposed to more practical projects here, but the conditions Well, it’s really not comparable to others, it will be a bit more difficult. If you choose this, I will let you participate in some key projects as soon as possible.”
“Of course, if you have other ideas of your own, I will try my best. Help, the choice is yours anyway."
"I choose the second one," Chang Haonan replied looking into Du Yishan's eyes.
This was his original idea, to prove his ability through course design and participate in specific projects as soon as possible, but the actual situation was smoother than previously expected.
"Really not going abroad?" Du Yishan smiled and asked again: "If you go abroad for further study, you can still build the country when you come back."
In fact, if Chang Haonan did not have this system, He may really choose to go abroad. After all, no matter which company is Britain, the United States, France or Russia in this era, they are far ahead of the domestic aviation industry. As long as they learn something after going abroad, it will be valuable experience and knowledge after returning to the country.
But with the help of the system, this gap no longer exists for Chang Haonan. If he goes abroad, he will contribute knowledge to others instead of learning knowledge.
This is contrary to his original intention.
(End of this chapter)