After moving, my cousin-in-law Xu Wenjing is quite satisfied. The new house is close to the obstetrics and gynecology hospital and just over one kilometer from the medical school, making commuting to and from get off work convenient.

The most important thing is that it is a private house, quiet and spacious.

Zhou Yan's parents and father-in-law and mother-in-law stayed in the capital for a few days and then returned to Dongyang.

As for Zhou Yan, after two days of leisure, he still had a lot of work to do when he came back.

There are many documents to be signed for the establishment of Xinghan's new terminal, and there are more things to do at Qingyan, especially the aviation design company...

"Mr. Zhou, the team responsible for the localization of D-18T has encountered a problem..."

"What's the problem?" Zhou Yan was a little surprised to see Xu Chongsheng's serious expression.

"The anti-surge design of the D-18T," Xu Chongsheng smiled bitterly, "Twelve turboprops, there is a propeller in front, and you made the anti-surge design of the compressor, so there is no problem. But they are improving the D-18T.

At 18T, the air intake volume and thrust are amplified according to the material properties, and as a result, the compressor characteristic curve is expanded..."

The so-called surge only occurs in axial flow multi-stage compressors.

When the air passes through the compressor, it is compressed step by step by the compressor blades. The final outlet pressure is generally many times greater than the inlet pressure. The pressure multiple is the so-called compressor compression ratio.

However, if the air intake volume at the compressor inlet is insufficient, although the compressor can naturally increase the pressure, this will cause the pressure of the blades on the rear stage to be much greater than that on the front, causing the air flow to flow in the opposite direction, causing the front and rear air flows to conflict, so that the compressor is "

"Choke" and surge occurs.

If this is the case, the damage is limited to the compressor, and at most the blades are damaged; the surge can be extended to the aero-engine system, resulting in insufficient air intake, and other systems "step by step" will cause a relative increase in fuel, deflagration in the combustion chamber, causing engine failure

Seriously damaged.

Put it on an airplane, and the problem becomes even greater...

Generally, when designing an engine, there is a surge boundary line on the compressor flow-compression ratio chart, and all engine compressor operating curves should be below the surge boundary.

The designers of Qingyan Aviation may not have considered everything when enlarging the design. They just blindly expanded the air intake volume and used materials to increase performance. This will naturally lead to the expansion of the compressor characteristic curve, and part of the boundary coincides with the surge boundary curve.

, this will cause the engine to increase the probability of loud surge within a certain compound range...

"Old Xu," Zhou Yan saw Xu Chongsheng's nervous expression and comforted him with a smile, "it's not a big deal. Just change the blade shape and improve the compression ratio at all stages of the compressor..."

To be honest, Zhou Yan is not worried about the surge margin problem during design.

The D-18T is a three-rotor design, with a three-stage design of air intake, compression and thrust. It inherently has a high anti-surge margin and has relatively large potential for improvement.

As for the insufficient surge margin caused by the "rash advancement" of Qingyan's young designers, Zhou Yan thinks it is a good thing: only by discovering problems can we learn how to solve them.

While chatting, Zhou Yan opened his computer, called up the backend of the aviation design software, found the updated design progress of the D-18T, and called up the entire design calculation book.

The original anti-surge design of D-18T is mainly a multi-rotor design and intermediate stage bleed.

The multi-rotor design is mainly used to adjust the rotation speed of each axis to prevent airflow cross-flow and prevent surge from the side.

The deflation of the middle stage is simpler and more crude. When surge occurs, the high-pressure gas pressure of the subsequent stage is released, and naturally there is no conflict.

As for the compressor blade design mentioned by Zhou Yan, it is similar to a check valve, using the blade design to increase the resistance to the reverse flow of airflow...

After opening the design file, Zhou Yan looked through it carefully, opened the aircraft engine design program, created a new project, and then made modifications to the compressor part while keeping the overall framework unchanged.

After completing the design, Zhou Yan used the simulation function that comes with the software to simulate it.

"Finished!" Zhou Yan saved the project example, then opened Word, wrote a revision opinion, and sent it to the leader of the D-18T design team.

"Is this all over?" Xu Chongsheng was a little envious and a little surprised when he saw that Zhou Yan solved the problem in three strokes, five by five, and divided by two.

"What else can I do? By the way, what else can I do?"

"I'm going to FAW next Monday," Xu Chongsheng said with a mysterious face, "Are you interested in going with us?"

"Okay, I just took my wife to relax..." Zhou Yan thought for a while and asked, "Oh, by the way, the feedback on Zhengxin's first batch of cars should have been out by now, right?"

"It's okay," Xu Chongsheng thought for a while, "but some people think that the four-cylinder engine used in our cars is a bit like the popular EA-888..."

What does it mean? It’s good or not. It’s just a deeply modified version. Except for the engine block frame, it’s almost impossible to tell it’s EA-888 in other parts.

Of course, based on the design of EA-888, no matter how modified it is, the driving experience will be similar to the original design.

"Isn't that great? Spend half the money and experience Quanquan A4 and A6," Zhou Yan smiled evilly, "If Quanquan accuses us of plagiarism, we can fool him. You dare to say that you have been imitated.

, has never been surpassed?”

As he said that, Zhou Yan suddenly remembered that the circle seemed to be a "light factory". After thinking about it, he opened his own data server, searched for it, and brought up a large number of technical files for car lights. Through the backend, he sent Zhengxin's technology

on the server.

When Zhou Yan passed the document, he did not avoid it, so he could see it clearly.

"Mr. Zhou, are you planning to follow other people's paths and leave others with no way to go?" Xu Chongsheng had a smirk on his face.

"We Zhengxin don't have a heavy-duty truck product line yet," Zhou Yan rolled his eyes and replied with a smile, "but as far as I know, WV Company has several heavy-duty truck companies in its hands..."

"Too……"

Xu Chongsheng nodded seriously.

Although Xu Chongsheng was not familiar with the system of Anxin Mall, he also knew that after the rise of e-commerce, logistics has also increased, and the main force of logistics is semi-trailer trucks.

Although the current domestic heavy truck product line is complete, compared with foreign products, although the price/performance ratio is superior, there is a certain gap in other aspects, such as fuel consumption and comfort.

China has always been WV's blood station, squeezing WV's living space and helping Qingyan Group achieve certain strategic goals, such as acquiring shares in Scania Trucks or MAN Trucks.

Taking over the heavy truck company under WV Group will help Zhengxin Automobile expand its product line.

"Oh, and I personally invested in that nanny car," Zhou Yan glanced at Xu Chongsheng, "Please urge Chu Xinyang. It would be best if we can get it done before our son or daughter is born."

"Chu Xinyang mentioned this," Xu Chongsheng thought about it carefully, "He said he would come up with two models, one for home use and the other for business."

"Then do it all. If there is insufficient funds, let him ask Hannah for..."

"No," Xu Chongsheng explained with a wry smile, "Chu Xinyang said he regretted a little bit and regretted letting you take the lead..."

"Are you jealous?" Zhou Yan rolled his eyes, "In the early stage, we had insufficient manpower, insufficient experience, and insufficient grasp of the market. This is understandable. But we should take this as a warning..."

"What about this car model..." Xu Chongsheng asked tentatively.

"I can let go of business cars. There is no market for family-friendly nanny cars right now. I have to keep the dominance..."
Chapter completed!