The Military-industrial Scientific Research System of the Academic Master Chapter 8

Chapter 8 A new design method! 【Kneel down and beg to read】

At this moment, the classroom door was pushed open, and four more people walked in from the outside.

This teaching building is shared by their entire School of Aeronautical Science and Engineering, so it is not surprising that there are other students in the classroom. If it is before the end of the semester, there may even be twenty or thirty people in the same classroom at the same time, so they are concentrating on their research. The four people involved in the plan didn't care at all.

“Haonan?” The leader of the four people who just came in was Chang Haonan's upper bunk Huang Zhiqiang. Naturally, he recognized the former at a glance: “You are also doing course design here?”

In fact, Huang Zhiqiang came here specially.

Since the beginning of the semester in March this year, Chang Haonan has been bitter and resentful. Almost everyone in the dormitory knows that he wants to design a fighter jet.

But for Huang Zhiqiang, Chang Haonan in that state is not worth worrying about. He knows very well where the opponent's upper limit is, and a person's ability will not be improved because of anger.

And he didn't think that was anything to be angry about.

However, Chang Haonan's uncharacteristically light-hearted attitude this morning made him feel a little uneasy, so he decided to "reconnaissance" to see how far the former had achieved.

"Yes, Lao Liu's class is not sloppy..." Chang Haonan did not raise his head, but continued to draw a sketch of the air inlet and the nose part on the paper, preparing to tell the other three people what they needed to do. matter.

In addition to the 10 credits of the aircraft design course, which is second only to the graduation project and will greatly affect the average grade point, Liu Hongbo will also invite many big names in the college to serve as judges in the defense session of the final course design. .

These people are often also the judges during the admission interviews for graduate students who are exempt from examination.

There is usually only about a month between the two events.

So any student who is interested in further study must devote 120% of his energy to this course.

The four people who just came in put the tools and books they brought on a table not far away. Then Huang Zhiqiang, the leader, slowly walked over to Chang Haonan: "By the way, how far have you progressed?"

“The design plan has just been selected, so it's early.”

Chang Haonan still didn't look up.

He really had no impression of Huang Zhiqiang, and he didn't take him seriously at all.

What I want to say next are just some preliminary parts of the design work, so I don't care about being heard by others.

And whether you can understand it or not is just a matter of words!

Zhang Man, on the other hand, was very wary of the approaching Huang Zhiqiang, and quietly took a step to the side, blocking the latter a few steps away from the table.

Huang Zhiqiang tried several times, but because the aisle between the tables and chairs was so narrow, he was ultimately unable to get over the obstruction.

"cut…"

Although there was no way to take another step forward, the petite Zhang Man could not block his view. Huang Zhiqiang easily saw the two black and white photos on the table and the sketch that Chang Haonan was drawing by hand, so of course I think this is preparation for reproducing the design through photos.

This immediately made him feel relieved again, he shook his head and turned to leave.

"Sure enough, big trash can only teach little trash. In the end, you have to copy it from the Soviets. Besides, aircraft design is not a sketch. What can you design based on two photos?" Huang Zhiqiang thought to himself, and sighed that he had just Some are too unfounded.

At this time, Chang Haonan didn't know that he had been scolded by others. He had already finished drawing two schematic diagrams and took another piece of paper to list the steps on it.

The other three people also quickly took out their notebooks and pens to take notes.

They still remember the way the second-year Ph.D. student, whose tutor is an academician himself, obediently took notes in front of Chang Haonan yesterday.

"The process is roughly like this. Because we are integrating the air inlet and the front fuselage, I will first select five different design initial values, which are the cone front body, or the half cone of the radome. "Angle." Chang Haonan pointed to the tip of the radome on the sketch and marked it with an alpha symbol: "What the three of you have to do is help me determine the design parameters corresponding to each initial value."

More than twenty years later, this process can be completely handed over to computers, but at this time, at least under their current conditions, many things still have to be calculated by hand, especially the relevant engineering manuals.

Zhou Shuwan and the other three nodded like chickens pecking at rice.

“Here are the steps. I'll explain them first. If you don't understand anything, be sure to ask.”

Chang Haonan said and wrote (1) on the paper.

“The first step is to set the cone precursor busbar, fix the initialization half cone angle and perform dimensionlessization according to the cone length.”

"The second step is for me to do. Average the flow field Mach number in the area near the inlet entrance as the baseline flow field design to calculate the Mach number. Because this is still an airplane after all, so the subsequent design points should be Choose around Mach 1.6, not too high.”

“The third step is to take the intersection of the three-dimensional internal transformation line of the inlet duct in the longitudinal symmetry plane of the cone precursor and the generatrix of the cone precursor as the installation positioning point, and calculate the axis of the incident inner cone shock wave in the inlet duct and the relationship between the axis of the cone precursor and the cone precursor The angle between the axes is used as the installation angle of the air inlet, and the specific calculation method is..."

“In the fourth step, the shape of the upper lip of the inlet is obtained by the intersection of the inner cone shock wave incident on the inlet and the lower surface of the cone precursor, and the shape of the inner lip is obtained by the intersection of the incident inner cone shock wave of the inlet and the lower surface of the cone precursor. The intersection of the longitudinal symmetry planes gives..."

“The fifth step is also done by me. Based on the three-dimensional shape of the inlet entrance, streamline tracing is performed in the selected reference flow field to generate the internal profile of the inlet..."

"The air inlet calculated according to these five steps is theoretically the optimal design at the half-cone angle. As for which of these designs is more effective after being installed on the MiG-21 fuselage, we need to do what we did yesterday. I'm going to do a CFD simulation. When the time comes, I'll run out the results, and you guys will be responsible for organizing the data and making charts, so we should be able to find the optimal solution intuitively.”

Of course, among the steps given by the system, there is a process of going to the wind tunnel at the end, but Chang Haonan simply ignored it.

If he could directly apply for resources like a supersonic wind tunnel, would he still be able to modify the J-7 here with three undergraduates?

After Chang Haonan wrote the last step on the paper, he threw the pen aside, stood up and looked at the three teammates in front of him: "Do you understand?"

There was a moment of silence…

"Well...I understand some of it, but I'm not sure what I didn't understand about the parts I didn't understand." Zhou Shuwan scratched his head with a troubled expression: "Let's go to the library first, and then we'll start calculating first. If I can't figure it out, I'll ask you again.”

"Okay." Chang Haonan nodded, and then packed his things on the table into his bag. Zhou Shuwan helped Zhang Man sort out the large amount of information she brought almost out of habit. The four of them Get up and leave quickly.

This classroom is not very large, and Chang Haonan did not deliberately lower his voice when he spoke, so the four Huang Zhiqiang sitting next to him also heard the content clearly.

“Brother Qiang, did you hear what Chang Haonan and the others were discussing just now?” One of them approached Huang Zhiqiang and asked in a low voice: “What do you mean, they seem to have some ideas?”

Hong asked this question, Huang Zhiqiang frowned and glanced at the teammate next to him with some displeasure.

He didn't understand either!

(End of this chapter)

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