"It is worthy of being a top student of Beijing Airlines, and I can see it at a glance, but I can't compare with you, so I went to work in a secondary school, and then I came out to do business with my brother-in-law." Hao Dagang waved his hand.

"Be modest, the previous secondary school is not better than the university." Chang Haonan looked at the blade design in his hand: "Not to mention anything else, if you can think of a wicker leaf type that combines two Bezier curves, it is really level, stronger than many undergraduates." ”

Wu Yifan, who was next to him, suddenly felt that something sounded wrong......

"Alas...... What's the use of saying this, it's not that Fuji Electric can't do it. Although we don't like the book, but, a small fan, just can't do it. ”

Hao Dagang touched the top of his head and sighed: "I don't know if you have a way to improve it?" ”

Before he knew it, his name for Chang Haonan had become you.

"Hmm...... Although the Bezier curve is used a lot in aircraft airfoils and turbomachinery, the problem is still relatively obvious. Chang Haonan replied:

"One is that it can't be partially controlled, any change will affect the entire curve, and at least half of the 16 parameters in this design are not independent; The second is that the quadratic curve such as the arc cannot be accurately expressed, so no matter how the parameters are adjusted, the smoothness of the connection between the Bezier curve and the arc cannot be guaranteed in the leaf profile. ”

Seeing that Chang Haonan was right, Hao Dagang's face was full of excitement and expectation: "It seems that you have an idea?" ”

Chang Haonan nodded and looked at Wu Yifan next to him: "Old Wu, sign the contract." ”

Strictly speaking, Chang Haonan should be regarded as a subcontractor, but Party A is aware and agrees to this subcontractor.

After signing, Hao Dagang directly took out a brown paper envelope from his bag and stuffed it into Wu Yifan's hand.

Deposit, 1000 RMB.

At this time, it's not a small amount of money.

The latter opened the envelope and checked the amount of money, then took out two "Great Unity" from it and put them in his pocket, and finally handed the envelope to Chang Haonan along with the rest of the money, even if the deal was concluded.

"Then the matter of leaf type optimization is entrusted to the two, this time our boss is bound to get the list of evergreen air conditioners, and I hope the two of you will take care of it more."

After Hao Dagang put away the contract, he got up and hugged his fists directly towards Chang Haonan and Wu Yifan, looking like he was still a little in the rivers and lakes.

But it's also reasonable, doing business in this era, and daring to run around with cash, there is something after all.

After sending Hao Dagang away, Wu Yifan took off the schoolbag behind him and handed it to Chang Haonan:

"Nanshen, how long will it take?"

"It's hard to say, but it's only about a week." Chang Haonan took the backpack, which contained a laptop and floppy disk that he had been very familiar with for more than half a month.

"One...... A week? ”

Wu Yifan's hand shook, fortunately, Chang Haonan had already grabbed the strap of the backpack, otherwise the computer inside would collapse before it could play its full value.

"They told me that it had been more than two months since the plan was designed."

"Well, the foundation of their basic design is actually good, and I can use non-uniform rational B-splines (NURBS) to parametrically reconstruct the fan blade airfoil and stack line, and improve it a little."

"Non-uniform...... What is it? ”

Wu Yifan suddenly felt that he not only failed to learn well in professional courses, but also probably did not learn Chinese well.

"I see that you didn't take classes well last semester, and the teacher's computer-aided geometry design course in Spell Casting was all talked about."

In order to adapt to his current identity, Chang Haonan also spent half a day reviewing what classes he had taken in the previous semesters, and it was impossible to make a mistake this time.

"Huh? I ...... in a hurry" Wu Yifan suddenly felt a pain in his flesh, if he could have listened well to the lectures last semester, then he could earn five thousand yuan now instead of just one thousand.

But soon this illusion was extinguished.

"Don't think too much, what Teacher Shi teaches is just the theoretical foundation, and the difficulty of this matter is being implemented." Chang Haonan patted Wu Yifan on the shoulder.

In fact, this is not the first time Chang Haonan has done this work, in the early 21st century of the previous life, he also designed an axial fan of almost the same size for Chang Hong Group in a similar way.

After all, the predecessor of Sichuan Changhong Group was a military enterprise that manufactured fire control radars, and although it was later converted to civilian use, it was still inextricably linked with the aviation industry, and it was not uncommon to entrust the latter to help with technical research.

"Okay, I can't earn your money." Wu Yifan shook his head and reluctantly accepted his fate, then took out a notebook from his pocket, wrote down a string of numbers, and then tore off a page.

"This is my pager number, you can just ask the pager to send me a completed one when you're done."

In 1996, Hanxian pagers were already very popular, not only displaying numbers, but also receiving short messages with a limited number of characters, similar to the youth Lite version of the SMS service.

Chang Haonan had already put on his bag and walked in the direction of the library at this time, but he just waved his hand behind to signal that he heard it.

……

Although the examination week in the second semester of the third year of the Department of Aircraft is very leisurely, it does not mean that other majors and grades are also like this.

As a result, the library was unmistakably overcrowded, and there were even quite a few people sitting on the floor.

So after borrowing a few reference books, Chang Haonan had a simple lunch and went to the computer room again with his things.

Even if he didn't use the system this time, his work efficiency is still quite high, after all, he was also a serious scientific research background in his previous life, how could he not even be able to do such a small project.

It's just that it should have been just a step-by-step process, but after doing it, Chang Haonan began to be a little dissatisfied.

He was not yet 30 years old when he did the project for Chang Hong, he was a novice engineer who had just graduated, and after that, he went through the next 20 years of experience, and completed a general design under the guidance of the system, and his thinking height naturally far exceeded that year.

"It's done, and the performance should be up to the mark, but it's ......"

Chang Haonan cut out and glanced at the design document - there is no standard format for doing a project for a small business, so he directly used the electronic version of the design document, and when the time comes, it will be good to store it in the computer and give it to Wu Yifan.

After all, the design object is just an air conditioner blade, and the rotational speed and gas flow rate are not very fast, so there are a lot of approximations and overlooks in the design documents.

"It's not transparent enough......" Chang Haonan muttered to himself at the screen.

These approximations and omissions are certainly acceptable in the field of home appliances, but he now has some new ideas.

I should be able to do better.

The axial fan can be regarded as a compressor that is too simple to be simple, but as an impeller machine, because the air flow in the compressor is diffused flow, the flow separation is more likely to occur and more severe.

Although axial fan blades with stable operating conditions do not need to worry about stall or surge, there is still a loss of efficiency due to the continuous development and accumulation of the surface layer of the end arm, and the noise caused by the refraction of the surface layer of the end arm.

In the past, since most OEMs only required to ensure that the fans met the flow needs, and the requirements for efficiency and noise were not very strict, no one bothered to pay attention to this issue, but now it is necessary to compete with Fuji Electric for performance......

"It seems that we can refer to the design ideas of some aviation engine turbines?"