At the same time, Jinghang University.

Since it was already the summer vacation, the master's students in the research group had returned home one after another, and only Fang Zhen, Yao Mengna and Chang Haonan were left in school.

Fang Zhen is ready to complete the final report of the wing flutter analysis project in one go.

Yao Mengna plans to stay in school and continue to learn about computational fluid dynamics simulation.

As for Chang Haonan......

In fact, it was because he predicted that Du Yishan should find a project for him to join, so he waited at the school.

Therefore, in the past few days, he has been continuing to study the influence of blade shape under different conditions on the separation of airflow in the surface layer inside the blade grid.

If there is any practical gain, it is that the editorial office of the Journal of Aeronautics and Astronautics has received a letter saying that his paper has been directly accepted and will be officially published in September.

and Wu Yifan gave him the remaining 3,200 yuan in final payment.

It shows that the previous fan design should have successfully defeated Fuji Electric's competitors.

Of course, the impact of this incident was limited after all, and it only increased Chang Haonan's scientific research points by 4 points.

Fortunately, whether it was designing the fan or doing wing flutter analysis for the 603, he relied entirely on himself and did not let the system help.

Therefore, now he has a total of 80 scientific research points in his hands, even if he faces some more complex problems, it should be enough to solve them under the premise of having ideas.

However, the leisurely fishing life did not last long.

Four days later, one morning, Du Yishan suddenly called and asked the members of the research group who were still at the school to prepare to attend an expert review meeting that afternoon.

Fang Zhen and Yao Mengna were all stunned when they heard the news, after all, they had no preparation before, and they had never seen such an urgent academic conference.

And Chang Haonan, who had been mentally prepared, had already guessed the true situation of this so-called "review meeting".

I guess there's a project coming to your door.

And it doesn't look like a general project.

……

Although he had been mentally prepared in advance, when Chang Haonan saw the situation inside at the door of the conference room, he still subconsciously took a deep breath and was stunned.

The size of the room is not large, with only two tables.

There are not many people in it, and there are only four of them counting Du Yishan.

But he happened to know two of the other three.

They are Liang Zhuoping, chairman of Huaxia Aviation Industry Corporation, and Yang Fenghat, deputy director of the 601 Institute and chief designer of the J-8-3.

Since the 83 project was approved much earlier than the 941 project, which clarified the chief engineer's responsibility system, the chief designer is equivalent to the person in charge of this model.

The last one is a woman, although I haven't seen it, but since I can sit with the previous ones and talk and laugh, I guess the identity will not be ordinary.

Such a configuration, even if there are only four people, is enough to be called a big scene!

At least Chang Haonan had never seen such a battle before he was reborn.

The first to be invited in was Fang Zhen.

However, he only stayed in for less than fifteen minutes before he came out.

Chang Haonan's mentality is still relatively stable, but Yao Mengna next to him hurried up:

"What did you talk about? What is the content of the project? ”

"Hmm...... Not exactly. Fang Zhen's expression was still a little confused: "In addition to the questions related to our group project, I also asked a lot of textbook knowledge that I learned before, fortunately, I basically remember it, and some things related to computational fluid dynamics, I am not familiar with this, but you two should be good at it." ”

After a brief chat, Yao Mengna was called in by the second one.

She stayed in there a little longer, about twenty minutes.

When Yao Mengna was asked about the situation inside, she obviously hesitated for a moment.

"It's similar to what Senior Brother Fang said just now, but in the end, the white-haired expert surnamed Yang asked me if the flutter simulation project we did for 603 could be used in combat aircraft."

Yang Feng's name is not very famous in this era, so it is normal for Yao Mengna not to know what the other party is doing.

"What did you say?"

"My junior brother told me about this before, when we studied the large aspect ratio straight wing, we regarded the research object as a beam wing and then used the dipole grid method, and the general combat aircraft are delta wings or swept wings, and there is no way to directly copy them."

Yao Mengna said and gave Chang Haonan a grateful glance, and now anyone can see that this posture is not ordinary, saying that it is a review meeting is actually more like an interview, so it must be beneficial to answer one more question.

Finally, it was Chang Haonan's turn to go in.

In fact, putting him as an undergraduate at the end would have meant something.

When Chang Haonan sat down behind the table near the door, although the movements of the four people opposite him did not change, he could clearly feel that there were some subtle changes in the atmosphere of the scene.

After a short opening session, the exchange between the two sides quickly got to the point.

The previous questions were all raised by Liang Zhuoping, and they were no different from Yao Mengna and Fang Zhen.

But when Chang Haonan said that he was recently working on the topic of using the blade bending and sweeping design to control the vortex structure in the impeller mechanical blade grid, the other two people next to him were almost at the same time.

Especially the woman Chang Haonan didn't recognize at first, and almost immediately raised her own question.

According to the introduction at the opening, she is the director of the Third Department of Systems Engineering of the Commission of Science, Technology and Industry for National Defense, surnamed Zhou.

"You also have research on compressor design?"

"Yes." Chang Haonan nodded: "Although there are indeed some differences between the overall design of the aircraft and the design of aviation power, the theoretical principles of fluid mechanics and the engineering methods of computational simulation are universal."

"In fact, not only compressor design, but also related materials and manufacturing processes are the same, and if we can grasp the basic theories and methodologies, it is completely possible to conduct cross-border research on a broader scale."

"Taking compressor blade manufacturing as an example, one of the major difficulties is that the CNC milling process will produce irreparable deformation due to clamping force, cutting force, internal stress and other reasons, which will affect product quality, which is generally believed to be solved only by processing experience and material upgrading.

"But in fact, it is possible to use the mathematical function relationship between the flow stress and the deformation parameters such as strain, strain rate, temperature and so on to establish a constitutive model of the material, so as to numerically calculate the deformation of the blade during the machining process, so as to achieve higher processing accuracy and more stable product quality."

"Another example is the turbine blade of the same aero engine, due to the long-term work under the conditions of strong thermal shock and complex cyclic thermal stress, so it is more demanding than the compressor blade, and needs to be manufactured by investment casting, but the efficiency of optimizing the process parameters through the traditional experience + trial and error method is very low, and it is very difficult for us as a late-developing country with insufficient experience and funds to rely on this method to surpass others."

"However, the investment casting process can essentially be summarized as two processes, filling and solidification, the former is a flow process that we are familiar with, while the latter is a heat transfer and phase transformation process, coupled with similar stress-strain problems to the milling process, the whole process can still be numerically calculated after comprehensive consideration, so as to achieve precise calculation and control of the casting process, greatly improving efficiency."

When Chang Haonan said this, including Du Yishan, the eyes of the four people on the other side who looked at him had changed.

This junior is far more ambitious than anyone could have imagined:

Whether it's design or manufacturing.

Beyond the experience accumulation and trial and error part that consumes the most time and money, and directly explain everything in a mathematical and physical way, so that the gap with developed countries can be narrowed in an all-round way with limited resources.

Even the corners......

Wrong.

Overtaking on the straights!