Chapter 93 A blessing in disguise

While Chang Haonan was thinking about ideas for improving the Kalman filter algorithm, the entire 83 Project team was certainly not idle. Instead, according to his deployment, they started working intensively on the impact of swept blades on the flow in the expansion cascade. A study of the effects of separation conditions.

Because I already have mature ideas and research methods, there are not many parts that require a flash of inspiration in the whole process. The main thing is to be step-by-step and careful.

With the help of Chang Haonan and the entire digital design team, the efficiency of experiments such as static pressure distribution and limit flow spectrum has been greatly increased. Since simulation methods can be used to predict the results, or at least the changing trends of the results, it is necessary to actually conduct The number of tests has been reduced by almost an order of magnitude compared to before.

But even so, after all, every experiment requires the 410 Factory to actually manufacture the required compressor blades, so the improvement of the entire engine still cannot be completed overnight.

Of course, for 606 institutes who are accustomed to working on a yearly basis, this work progress is almost like a dream. Even Yan Zhongcheng was shocked by the smoothness of the test process.

In short, according to Chang Haonan's own initial estimate, it would take about twenty days to come up with an improvement plan.

If it weren't for the fact that Yao Mengna accidentally saw an article from "Journal of Aeronautics and Astronautics" at the end of the first week.

……

Time goes back to the time when Chang Haonan had not yet joined the 83rd Project research group.

In Bingcheng, more than 500 kilometers away from Shengjing.

Doctoral student Zhang Donglin is using the classic ROTOR37 blade to study the impact of tip clearance height on the flow field in the Aerodynamics Laboratory of Bingcheng University of Technology.

In fact, it is similar to the project Chang Haonan is working on, except that the research content is relatively rough.

Moreover, due to the lack of support from simulation methods, the research methods of their research group are still based on traditional large-scale experiments. In addition, the funds are not very sufficient, so the efficiency is not high.

"Senior brother, there's another power outage in the laboratory."

Zhang Donglin's junior brother puffed out his cheeks and opened the office door with a depressed look on his face.

"I know." Zhang Donglin pointed to the two computers in the office that had been shut down due to a power outage: "But there is nothing we can do, we can only wait."

For China in the mid-90s, power shortage was still a major problem plaguing the whole society.

In fact, until about 2010, for many non-first-tier cities, power supply interruptions in residential areas due to insufficient power were still a relatively common thing.

Relatively speaking, Bingcheng University of Technology, as a university directly under the Commission of Science, Technology and Industry for National Defense, naturally has a very high priority in terms of power supply.

But even so, except for some particularly important laboratories that have independent power supply lines or even self-provided generators, power outages are still a difficulty that needs to be faced frequently.

So Zhang Donglin was not too surprised. He just looked at the two computers and muttered:

"I just hope that the data in the computer will not be lost due to a sudden power outage..."

His junior brother also lay down on the two chairs spliced ​​together next to him.

"In that case, senior brother, let me catch up on some sleep first. If you call, you can call me again."

Because the summer vacation is not over yet, there are only two of them in the whole office. The junior brother and Zhang Donglin have always had a good relationship, so they are more relaxed.

Zhang Donglin, who was also swept away by fatigue, nodded, but almost instinctively lay down on the table.

About an hour later, the two of them were woken up by a phone ringing.

It was their tutor, Professor Lin Haijun, who said that the school's metalworking center had sent a new batch of blade samples and asked them to pick them up.

The fact that the phone was ringing meant that the power supply had been restored, so Zhang Donglin asked his junior brother to go back and do experiments while he began to inspect the batch of blades.

Then he saw a scene that made people hypertensive.

Due to some stains on the paper design drawings during the handover process, the worker responsible for the production process mistakenly opened a chord-wise channel on the surface of the blade that penetrated the suction and pressure surfaces.

More than 30 blades in this batch were all scrapped.

Fortunately, he checked it carefully before signing for it. Otherwise, if he had just signed his name, the loss would have to be borne by the research team.

Naturally, the blades used for basic research in the school cannot be made of special expensive materials like those actually used in aerospace engines, but even so, it is still a large expense for their young mentors.

After spending a few minutes to stabilize his mentality, Zhang Donglin contacted the instructor using the phone number of the director's office of the Metalworking Center.

After all, the school's youngest associate professor still has some status. After a battle, the Metalworking Center finally promised to re-manufacture a batch of blades for them. However, due to production scheduling issues, it would take an extra 4-5 days.

Now that these blades that have been processed into scrap products have been sent, no one is willing to take them back.

Therefore, Zhang Donglin, who was a little worried about the progress of his graduation, returned to the laboratory depressedly, casually placed the discarded blades in the corner, and then returned to the office to continue sorting out his previous experimental data.

This minor incident was quickly forgotten.

It wasn't until noon the next day that the junior brother hurried in again.

"Brother, our experimental equipment may be broken."

Zhang Donglin felt as if his heart stopped beating for a second.

"What's wrong?"

"I replaced a new set of blades, but compared with the previous series, the experimental data...are very abnormal."

"New leaves?" Zhang Donglin was stunned for a moment, and then realized that he had forgotten to notify the junior brother who was doing the experiment after putting the damaged leaves in the laboratory yesterday.

This finally made him relax, who was nervous just now, and waved his hand towards his junior brother who was standing at the door.

"I forgot to tell you that the blades piled next to the cabinet behind the door are scraps accidentally processed by the metalworking center. It is normal for the data to be wrong when you install them."

"Waste...waste?"

Junior brother's surprised voice made Zhang Donglin raise his head again:

"Yes, you should pay attention when installing the blade. There is a slit on the side."

"But senior brother, judging from the experimental results, the performance of those blades... is very promising, but the fluctuation is very serious."

"Ok?"

He briefly thought about the papers and reference books he had read in the past, and did not recall that anyone had studied the impact of chordwise slits on the pressure front edge and trailing edge of a blade.

After all, intuitively, this will only cause the flow field inside the compressor to become more turbulent.

However, Zhang Donglin, who has been studying for a PhD for three years, understands that it is in these things that are usually ignored due to intuition that new discoveries are more likely to be found.

"Take me to see it."