The military-industrial scientific research system of the academic master.

Faced with Chang Haonan's request, everyone in the meeting room showed some hesitation.

Although the Gaofa Group's experience in aero-engine design is still somewhat insufficient, some of its people have gone through the training of the WS-10 project. A numerical simulation of a fan, done mainly out of curiosity, without the need to pursue excessive precision, would not be difficult for them.

But on the other hand, this is, after all, a matter of being a supplier to others, or even a second-tier supplier.

Although at this point in time, any opportunity to participate in major international aviation projects is extremely valuable to China, as suppliers, they only need to make sure there are no loopholes in the contract and then make the products according to the requirements provided by Party A.

As for whether the client's design is reasonable or not, and the resulting progress of the entire project, it is actually not their turn to worry about it.

What's more, considering that the design team of SeA650, especially the permanent magnet power generation system, mainly comes from the 606 Institute, it is highly likely that this project has no particularly direct relationship with the Gaofa Group.

However, the more important reason is.

The computing power resources in Haojing are indeed quite tight.

Although the timeline has changed dramatically, it is still only 2003.

In 2003 of the previous life, the JH-7A, China's first model that fully adopted computer-aided design during the development process, had not even entered service.

One of the biggest obstacles that the JH-7A needed to overcome during the design process was that the supercomputer performance at the time did not support high-precision meshing operations for the entire machine or even for large components.

This hardware condition almost sent the JH-7A back to the drawing board.

In fact, when Chang Haonan first arrived at the 96 Institute in 601, the operation of converting quadrilateral grids into "pseudo-triangular" grids and then performing calculations was originally developed to solve this problem.

Of course, with the support of a large number of industrial and scientific research needs, the performance of the Sugon 3000 series has now reached the forefront of the world and is no longer the same as before.

However, for aircraft engine designs with higher simulation sophistication, the amount of funds available is still not as abundant as it would be in ten or twenty years.

Finally, Zhang Zhenhua, who was relatively familiar with Chang Haonan, asked cautiously:

"Boss Chang, the entire group is now concentrating resources on the preparatory work for the WS-20 project. Do you think... can this matter be put on hold, at least until the project is approved?"

But Chang Haonan waved his hand:

"Don't think about it that way."

"From a broader perspective, this can be considered as part of the preparation for the WS-20 project..."

Not only Zhang Zhenhua, but several other people around him also looked puzzled.

After all, although the design of this fan is indeed a bit strange and its size is larger than that of ordinary small bypass ratio military engines, it is obviously not the same as the WS-20 in any case.

Faced with puzzled looks, Chang Haonan had no choice but to explain further:

"In essence, the WS-20 uses the mature core engine of the WS-15, and the greatest design difficulty lies in the fan."

"So, although the properties of the engines are not exactly the same, and we are not planning to copy or learn from the WS-20, it will never hurt to learn more about other people's experiences, just like taking an exam."

After saying this, he remembered that someone had just raised the possibility that the British provided a fake design.

Then he added half-jokingly:

“Even wrong experiences can still be valuable.”

Originally, this sentence was just a casual remark.

Because Chang Haonan also felt that, on the one hand, the British would not make such an obvious fake to fool people.

Everyone knows that making aircraft engines is difficult, but most of the difficulty lies in the combination of design and production.

It's just a simple design parameter, and it's not even complete. It's not worth putting so much thought into it.

On the other hand, according to Jin Xu's feedback, the other party handed the information to Ren Bingda only two days after both parties finalized their intentions.

This time is basically the time to delete the most sensitive information and check it again.

There is no time to make a fake one.

However, no one expected it.

His unintentional words actually came true...

……

After Chang Haonan briefly assigned the tasks, the Gaofa Group divided into three teams responsible for analyzing and simulating this fan... or strictly speaking, this blade type.

The reason why it is divided into three parts is because the British have indeed concealed a lot of information that seems insignificant but is very important in operation.

For example, the number of blades on a fan.

As a result, Chang Haonan could only deploy three more likely options based on his own experience and the blade design provided by the other party.

If it is not right, adjust it slowly.

As for Ren Bingda...

According to his initial estimation, testing the performance of the fan was not a particularly complicated task.

It will probably take a few days to get a rough preliminary result.

It’s not too late to sign the contract after verification.

Therefore, for a period of time afterwards, Chang Haonan still held two positions in Gaojing, responsible for the work of both the WS-20 and the communication relay system.

The specific simulation task was assigned to Zhang Zhenhua.

then……

The preliminary results showed that it was indeed taken out on the fifth day.

But the result itself was very different from Chang Haonan's previous estimate.

Regardless of the number and layout of blades, the blade design given by the British cannot be said to be exquisite in every aspect, but at least it can be said to be useless.

Even Zhang Zhenhua couldn't help but complain:

"Boss Chang... if you really want to design a fan with a very low stage pressure ratio and intake efficiency, very high processing difficulty, and a small surge margin... or a low-pressure compressor, to be honest, it is still... quite difficult."

Looking at the calculation results, Chang Haonan began to doubt the software and algorithm he developed for the first time...

However, Zhang Zhenhua quickly saw through Chang Haonan's thoughts and quickly added:

"Boss Chang, I supervised the entire work. The three computing teams completed the computing tasks independently without any communication in between."

"Also, we actually got the calculation results yesterday afternoon, but because it was so... incredible, I asked them to verify the calculation method using the Rotor 67 standard blade profile, and they didn't find any obvious problems..."

The meaning of these words is very clear.

It is unlikely to be a human calculation error.

It is also unlikely that there is something wrong with the algorithm or program.

It's just that the design provided by the British is wrong.

But the problem is...

Never mind Rolls-Royce.

Even China a few years ago was not able to design a fan of this level.

“Could it be that this is really fake data?”

Zhang Zhenhua didn't quite agree with this speculation at first.

But there doesn't seem to be any other more reasonable possibility now.

Chang Haonan did not answer immediately, but just flipped over the short report and read it twice.

My brain is a bit confused:

“But wide chord, sweep, air structure… these are indeed the current mainstream development directions.”

"And you see, Ye Shan's part has design space left for active boundary layer control technology... This shows that the British have actually been paying attention to our research results a few years ago. If they want to provide false data, they can just delete these details..."

Active boundary layer control is the technology used by Chang Haonan in the design of WS-10.

Of course, there is no record of export of WS-10 itself, but it was also used in the development process of M88 and SeA650.

It is normal for the app to be discovered and tracked by the British.

The two people were puzzled and fell into entanglement again.

After a period of silence, Zhang Zhenhua broke the silence again:

"In fact, there are more problems with this blade..."

"Oh?"

Chang Haonan also became interested at this time.

He really wanted to know what new things could be done with an engine fan.

"All three teams reported to me that they found that the rigidity of these blades was very low during the preparation for the fluid-structure interaction calculation. If any common material properties were substituted, elastic deformation would inevitably occur... So in the end, they had no choice but to give up the structural problem and produce pure CFD results..."

For Zhang Zhenhua, he was just complaining about his experience at work.

But Chang Haonan was suddenly awakened by his words:

"Elastic deformation?"

He quickly picked up the report that was already on the table:

"What if we consider the aerodynamic loads in the operating state?"

"Ok?"

Zhang Zhenhua also raised his head, but had not yet reacted to the meaning of Chang Haonan's question.

The latter had no choice but to explain further, and at the same time took out a pen and paper from the side and drew a simple diagram:

"You see, the blade shapes of these blades are indeed very strange when they are in a static state, that is, in a cold state. But when they are in a working state, that is, in a hot state, the blade shapes will change accordingly..."

"This deformation in turn changes the aerodynamic forces, which in turn lead to further elastic deformations... This constitutes an interaction between structural deformation and aerodynamics..."

After all, Zhang Zhenhua is also an old engineer. He just couldn’t keep up with the leaps in his thinking.

Now that it has been sorted out like this, how can I not understand its meaning?

"Like the wings in airplane design?"

Although his major is aero-engine design, aviation technology is inseparable, and the Gaofa Group has been engaged in various businesses in the past, so he would not be completely blind to the problem of external leakage.

"That's right!"

Chang Haonan nodded:

"I suspect that the British idea is to completely abandon the blade stiffness in order to reduce the weight of the fan as much as possible, and use structural analysis to reverse the optimal aerodynamic geometry of the blade under the design conditions, that is, the original hot blade shape, in order to obtain the cold processed blade shape, that is, the pre-deformed blade shape."

"The data we obtained is the cold-processed blade shape. If we directly use this blade shape to analyze aerodynamic performance, we will naturally get a very bad result!"