Chapter 17 The Favor of Academicians [Recommended above, I beg to read it]

On the other side, Chang Haonan still didn't know that his "stepping stone" had achieved results far beyond expectations.

He was catching up on sleep in the dormitory at this time - he had been suffering from liver disease for more than half a month, and even though his physical condition had returned to the most energetic state of his early 20s, he really felt a little unbearable.

Until a sharp knock on the door woke him up.

"Huh?" Chang Haonan reluctantly opened his eyes, and then spent about two seconds to make sure that he was the only one in the dormitory, so he reluctantly got out of bed and opened the door.

Standing outside the door was Yan Lu, the counselor in charge of the entire aircraft department.

Fortunately, he wasn't in the habit of sleeping naked.

"Sister Lu?"

Yan Lu is not much older than the junior students and has a good personality, so everyone usually calls her Sister Lu, Sister Lu.

There is no woman who doesn't like to be called younger.

However, although she has no airs in front of students, Yan Lu is the counselor in charge of the entire department after all, and she rarely directly interacts with a specific student.

So it's quite rare for her to appear here.

"Classmate Chang Haonan, Academician Du just called my office and said he wanted you to come to his office."

Yan Lu's tone was a little excited. Although Du Yishan didn't tell Chang Haonan what to do just now, judging from the other party's tone, it shouldn't be a bad thing.

In addition to being a counselor, Yan Lu is also the deputy secretary of the Youth League Committee of the college, so if the students achieve something, she can also be credited with it.

At least it can be written into this year's Youth League Committee work report.

"Academician Du...Academician Du Yishan?" Chang Haonan was even stunned when he heard the name.

To be honest, he had never thought that he could reach the top by relying on course design and be favored by Du Yishan, but when things really developed in this direction, he was still in a daze for a moment.

"Who else could it be? You quickly change your clothes and ride my bike over there." Yan Lu looked at the basketball uniform that Chang Haonan was wearing as pajamas. Although it was not a formal occasion, she was dressed like this to meet the academician. Still a bit much.

"Oh... ok, I'll change right away." Chang Haonan closed the door with his backhand, quickly changed into a set of shirts and jeans, and then put some things he might need into his bag and carried it behind his back.

His previous plan was to follow Professor Liu Hongbo to make improvements to the Xinzhou 60 after receiving his graduate degree in the second half of the year, but now the person offering the olive branch suddenly became Academician Du, which made Chang Haonan feel a little hopeful.

Ten minutes later, Chang Haonan rode a women's bicycle to the downstairs of the aircraft department building.

"Classmate Chang Haonan!"

Before he could park his bicycle, he heard a familiar voice coming from not far away. When he looked up, he saw that it was Professor Liu Hongbo waiting for him at the door of the building.

"Teacher Liu."

"Alas..." Liu Hongbo's first reaction after seeing Chang Haonan was to sigh.

Looking at Professor Liu's complicated expression in front of him, Chang Haonan was a little confused for a moment.

Many possibilities flashed through his mind in an instant.

"Just call me senior brother from now on." Liu Hongbo turned around and walked into the building with a bitter look on his face: "Let's go, I will take you to see Academician Du."

I'm so stupid, really. I just knew that Academician Du could prove Chang Haonan's innocence with just a phone call. I didn't know that he would actually steal my student...

Chang Haonan naturally didn't know what kind of ups and downs Liu Hongbo had experienced in the past half day, so he just followed him to Du Yishan's office on the fourth floor.

"Hello, Academician Du."

"Classmate Chang Haonan, right?" Du Yishan showed a kind smile and stretched out his hand to motion to another chair in front of him: "Sit here and chat."

Liu Hongbo next to him had long been accustomed to this, and he sat on a sofa against the wall.

"I've just seen your team's design, and it's very well done." Du Yishan opened his mouth and gave a rare high evaluation for him.

"I see the division of labor written in this design description. Are you responsible for the overall program control and all the computer simulation work?"

"Yes." Chang Haonan nodded.

Now is definitely not the time to be modest.

"Tell me what you think. How did you come up with the idea of ​​designing a fighter jet?" After Du Yishan finished speaking, he picked up the thermos cup and took a leisurely sip of water.

Faced with this problem, Chang Haonan of course told the truth: "Because of what happened at the beginning of this year, I feel that we cannot always let others bully us. Since the air force is not strong enough, then I want to design an aircraft that can quickly improve combat effectiveness. "

After hearing Chang Haonan's answer, Du Yishan's eyes changed slightly.

Such a simple emotion, but it is no longer common in this age when people's minds are changing.

What's more, the student in front of me not only has simple emotions, but can also transform emotions into persistent actions.

It reminded him of his colleagues in his youth.

"Compared to strong enemies, we are still relatively weak now." Du Yishan put the water glass aside: "But as long as I have your energy and mobility, it is not impossible for me to catch up with them."

"Of course, and I believe that day will not be far away." Chang Haonan replied firmly.

Du Yishan did not continue this topic, just smiled and continued to ask: "So, after you had the idea of ​​improving the J-7, how did you come up with the idea of ​​taking the mandibular air intake route?"

"The critical moment has come!"

Chang Haonan took a deep breath and gave the explanation he had thought of for a long time:

"What the J-7 currently lacks most is its beyond-visual-range combat capability, so the starting point for my thinking is to leave a nose space for the aircraft to install a radar."

"The idea of ​​enlarging the nose cone has almost reached its end on the MiG-21bis and my country's J-7C, so I considered directly changing the original nose air intake method, and the mandibular air inlet has the least impact on the overall structure of the aircraft. kind of."

"In subsequent simulations, I found that because the outer compression flow field of the nose radome is difficult to match the inner contraction flow field of the inlet, there is a problem that the compression of the side wall of the inlet is stronger than the compression of the upper wall."

“At the same time, the inner cone-shaped incident shock wave of the inlet intersects with the cone-shaped precursor to generate a crescent-shaped upper front edge, resulting in high pressure on both sides in the near-wall area near the upper front edge of the inlet. The transverse pressure gradient on the symmetry plane forces the boundary layer developed from the cone precursor to converge towards the symmetry plane of the inlet, thereby forming a low-energy vortex structure that develops downstream, seriously reducing the overall performance of the inlet."

"So I considered that instead of designing the aircraft and the power unit separately, as well as the internal flow and the external flow, the radome was designed as an integrated design as the conical front body of the inlet, using the longitudinal symmetry plane to face the transverse pressure gradient on both sides. , to achieve the displacement of the conical precursor boundary layer to reduce the impact of the precursor boundary layer on the flow channel in the intake duct, which is the idea reflected in my design description."

After all, Chang Haonan was a genuine aeronautical engineer before he was reborn. He did not only know the things that were taught to him systematically, so the answers he gave were clear and well thought out.

From the initial indicator requirements, to the subsequent trial and error encounters, then to the discovery of the problem, and finally to the solution of the problem, a complete closed loop of thinking is formed.

This is the mental journey that only the true designer himself can explain clearly.

It's not written out in any design instructions or manuals.

And when Chang Haonan explained his design, Du Yishan's eyes were full of approval.

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