Spark

On the other side, Chengdu.

Chen Nian was sitting in the office, looking at the thick draft paper in front of him with a sad face.

As early as a few days ago, he had already entered the normal working state. Now, apart from the fixed daily study schedule, he spent all his time on the theoretical analysis of the two-stage counter-rotating lift fan.

It has to be said that this is an extremely complicated job.

Although we have obtained data on the F-35's airframe design and center of gravity, it is still difficult to deduce the precise design data of the fan placed behind the seat based on these things.

So, there is only one thing he can do:

Refer to similar aircraft as much as you can, and look for clues from them.

During this period, Chen Nian consulted a lot of information, but there were very few that were actually useful.

In fact, the world's first vertical take-off and landing fighter appeared in 1950, but the "vertical take-off and landing" method of that thing is to directly make the thrust of the engine greater than the power of the body, and let the plane take off standing upright. Question doesn't help.

Similarly, the second-generation STOVL with additional take-off and landing engines and the third-generation STOVL with tilting engines are also useless, and the design logic is completely different.

The only useful thing is the fourth-generation dual-mode STOVL, but this thing. Only F-35 has it.

Chen Nian felt as if he had fallen into an endless loop.

After a busy week, he didn't make any progress on the theory.

So, he secretly made up his mind:

If you are still stuck here within two days, then use the plug-in directly.

The reason why the target is set to two days later is because according to his current source point growth rate, basically in about 10 days, he can accumulate enough source points to analyze the core technology of the two-stage counter-rotating lift fan.

If it continues to be consumed, there will not be enough time to study, which is equivalent to a net loss of 0.18 points per day

Thinking of this, Chen Nian could not help but sigh.

He reluctantly pushed away the messy papers, stood up and walked out the door, wanting to take a few breaths of fresh air.

Unexpectedly, as soon as he went out, he bumped into Yang Wei who happened to come looking for him.

"Chen Yunyong's done it!"

Hearing his words, Chen Nian was overjoyed.

"Fixed? How did you do it? When will it be in place?"

"I exchanged it with an EC-130H. Speaking of which, it's all thanks to you."

"It is estimated that it will be in place next month at the latest. At that time, a group of experts in the aviation field will come with him, starting from Shanghai, passing through AH, and flying over by military plane."

"Well, what's the main field?"

Chen Nian continued to ask.

"We have everything, including those engaged in finite element elements, aviation development, and materials. A small half of them were abducted by Chen Yunyong from the United States."

"Those people basically worked in private companies before, and they themselves have a certain willingness to return to China. After review, they were allowed to come back."

"By the way, you don't mind that, do you?"

Yang Wei asked slightly worried.

In fact, for him personally, his origin and past experiences are not too important.

As long as it can pass the review and meet the relevant confidentiality requirements, then he believes that some experience of working abroad can actually be properly relaxed.

After all, they chose to stay there not because they wanted to betray, but simply because they were attracted by better conditions.

This is a very real problem.

After finally learning it, who wouldn't want to sell their skills for a good price?

Money is the hero's courage. When everyone is generally in trouble, pursuing money is not a heinous matter.

What's more, in terms of treating talents, we have not given enough respect in the past. This is a problem that really needs to be reflected.

Now, the higher-ups have begun to consciously improve their salaries to attract talents, so it is even more important to show our sincerity regardless of past suspicions.

This also has the chill of buying a horse bone with a lot of money in it.

Of course, he thinks so, not everyone thinks so.

Objectively speaking, there are still many people who are prejudiced, but they just hope that Chen Nian is not included among these people.

Hearing his words, Chen Nian smiled and replied:

"Of course I don't mind, as long as you follow the rules."

"But this Mr. Chen is really amazing. Ren Meidao earns a lot of money, and he was able to abduct him back."

"Ham, everyone still has some ideals, and it doesn't necessarily mean that money worship is paramount."

Chen Nian nodded in agreement. These days, there are indeed some experts and scholars who still have ideals.

The domestic economy is not good, and there are many temptations abroad. They really rely on their blood to support them.

"How are you preparing here? Is there any progress?"

"No."

Chen Nian answered without any hesitation.

"Do you need to apply for foreign aid? We can talk to Russia, they have similar research."

"Don't use it for now, give me a few more days."

"Don't worry, Xiao Nian, the progress of this kind of project is really not measured by days."

Yang Wei said dumbfoundedly.

Good guy, I still want to comfort him, telling him that it doesn't matter if the output is two months late, but what did they say?

Give it a few more days.

This is not a conversation on a channel anymore.

The two chatted for a few more words, then Chen Nian walked out of the room to relax, and when he came back, his thoughts were much clearer.

He spread out the draft paper on the desk, re-entered the state, and planned to start the deduction from scratch.

According to the take-off quality of the F-35B aircraft, Stallion has adjusted the overall layout of the aircraft for the lift required for take-off, which is the premise of everything.

According to the center of gravity data and the body weight data, the total lift required for the F-35B vertical takeoff should be about 18.14 tons, but this part of the thrust is not completely provided by the lift fan. Among them, the vector nozzle and the attitude adjustment nozzle It also needs to take 55% of the lift.

In other words, the thrust provided by the lift fan should be around 8.16 tons.

In order to generate this part of lift, the lift fan not only needs to have a relatively large pressure difference, but also needs to pass through enough flow.

Then, the diameter of the lift fan will be strictly planned.

This part is the hardest.

Frowning, Chen Nian carefully recalled the data he had seen in his previous life, and referred to the thrust of the conventional thrust fan, combined with the overall body size of the F-35, finally determined a number:

The diameter of the lift fan is 1.27m.

This is the only reasonable size in the entire body layout.

In this way, the inlet mass flow rate of the fan should be able to reach about 210kg/s.

"Assume that the 0-0 section is the pressure far field, the inlet is the 1-1 section, and the outlet is the 3-3 section. The lift fan inlet Ds=1.27m, the inlet hub ratio Dh-s=0.454, liter

Force fan efficiency η=0.87, nozzle total pressure recovery coefficient σe=0.98, q=204kg/s, assuming boosting ratio is π*”

".q(λ) is a dense flow function, so it can be deduced that q(λ), Ma1, p1, T1 on the inlet section"

"The lift fan inlet airflow velocity V1 is given by the continuity equation."

"Compressor Efficiency Formula Available"

"The final lift expression is"

Chen Nian silently recited a series of calculation formulas in his heart, and the movements of his subordinates became smoother and smoother.

At this moment, his brain entered a state of full capacity, and even beads of sweat began to ooze from his forehead.

He is like a supercomputer, frantically calling knowledge from two time-spaces and two worlds, trying to fuse them together to get the final result.

"Therefore, in order to further accelerate the air, the outlet of the lift fan is a tapered nozzle, which can give constraints: Ma3\u003c1, A3\u003cA1"

"In addition, considering the ground effect during takeoff and landing, the lift fan has lift loss, and the general loss rate should be around 50%"

"Traversing the variation of outlet cross-sectional area A3, lift F, and boost ratio π* with λ in the range of velocity factor λ∈[0, 1]"

2.165!

The total pressure ratio is 2.165, and the generated lift can take into account the target lift and the required lift after ground effect!

Chen Nian dropped his pen excitedly, he subconsciously stood up and moved away from the table, and then moved closer in disbelief to observe the hard-won result.

This is the first time.

Through the calculation for the first time, a credible result was obtained!

Moreover, according to my own calculations, if the tolerance is considered, it is relatively safe to set the total pressure ratio of the lift fan to 2.2 to 2.4, which can ensure that there are differences in the aerodynamic layout of the J-20B and F-35B. Can achieve similar STOVL performance!

Chen Nian dropped his pen excitedly, and ran to Yang Wei's office impatiently.

He must share this news immediately, because the significance of this news is too great

On the other side of the sea, it was already late at night.

Chen Yunyong sat in front of the desk, and on the desk was a large pile of draft paper that was almost identical to Chen Nian's.

And the problem he is trying to solve is the same as Chen Nian's, which is to calculate the appropriate total pressure ratio required by the two-stage counter-rotating lift fan.

This is not his first attempt.

It should be said that he has been doing this work for five full years.

In the past five years, he tried various methods to obtain as many resources as possible within his ability. At the same time, he also asked many friends in the same industry for help, but the progress was always slow.

As Dick had told him at the time, his research was too rudimentary.

But why junior?

In the final analysis, the most critical "1" for startup is still missing.

But recently, he suddenly felt inspired.

Maybe, I started in the wrong direction.

In particular, reasoning from the perspective of pure data is inherently difficult to obtain correct results.

What is really effective is the physical experiment.

From the perspective of aerodynamic design, it is necessary to use a large fan in order to meet the requirements of the airframe layout.

In this way, the data range will be greatly reduced, and the difficulty of calculation will be correspondingly reduced.

——

This doesn't seem to be a very rare idea, and it's not that he hasn't thought of it before.

The point is, he didn't have any information about the F-35B in his hand before, and he only had a few words, which were useless.

But now, after setting the time to return to China, the special staff passed the information to him, so his research also began to advance by leaps and bounds.

In less than two weeks, he had sorted out his calculation ideas.

And today, the first result was calculated!

2.21.

Under this pressure difference ratio, J-20 will achieve a perfect fit with the STOVL system, and the theoretical problem of the two-stage counter-rotating lift fan will also be completely resolved.

Chen Yunyong had an excited look on his face, and he really wanted to shout a few times to vent the turbulent emotions in his heart.

But he knows that in his current situation, even celebrating is a luxury.

So, he had no choice but to collect all the manuscript papers with trembling hands, fold them into a pile, and then walked towards the bathroom step by step.

Liu Huixia noticed his movements, stepped forward and asked with concern:

"Yun Yong, what's wrong?"

Chen Yunyong lowered his voice and said:

"It's done."

"Fan? Finished?"

"That's right!"

He nodded solemnly, with an uncontrollable smile on his face.

Liu Huixia's expression also became excited, she held Chen Yunyong's hand tightly and did not say a word for a long time.

The two just looked at each other silently. After a long time, Liu Huixia asked:

"Is it going to be burned?"

"Yes, burn it, everything is already in my head, we can't leave any excuses for those white ghosts."

"Okay, I'll help you!"

After saying that, Liu Huixia turned around and went to the kitchen to fetch a lighter, then hesitated for a moment, and brought the iron pot for cooking into the bathroom.

"Put it in and burn it one by one, so as not to trigger the smoke alarm."

"I know."

Chen Yunyong lit the first page of manuscript paper, and bright yellow flames rose up, reflecting the mixed feelings on his face.

"Finally. This matter has finally made some progress."

He said with emotion.

"With this first step, when we go back, no matter how bad the conditions are and how weak the foundation is, we can catch up bit by bit."

"But it just might take a long time."

"Time, Huixia, sometimes I really feel that our time is too limited."

"Ten thousand years is too short, seize the day and night."

Hearing his words, Liu Huixia smiled lightly.

She threw a piece of manuscript paper into the pot, and then comforted her:

"You see, you are still pessimistic in nature."

"In fact, the development of science and technology is leaps and bounds. Maybe one day, when you don't expect it, the problem will be solved suddenly?"

"Just like you solve the fan problem, isn't it the same process?"

"No, not the same."

"This problem can be solved after five years of accumulation. But, how many five years do we have?"

"Your five years, plus other people's five years, will create different results."

Liu Huixia continued.

"Unless, you really don't believe in them at all, you don't believe in that land."

"That's not true."

Chen Yunyong shook his head lightly, hesitated for a moment, and then said:

"I'm just regretting that if I hadn't chosen it, maybe everything would have been different."

"it does not matter."

"Every road will have different twists and turns - think about it in a good direction, maybe in China, someone has already taken your place?"

Speaking of this, Liu Huixia showed a sly smile on her face.

"Perhaps, the result you are making now has already been made by someone else?"

"At that time, I really don't know whether you should be happy or disappointed."

Chen Yunyong laughed and replied:

"Of course I'm happy."

"And, I'd be happy."

His expression became a little fascinated, the flame in the iron pot was still burning, and the faint blue smoke gradually drifted away.

This wisp of smoke penetrated the window of the bathroom, and with the wind, it floated higher and farther into the sky.

Chen Yunyong watched this scene with some ecstasy.

At this moment, he seemed to be able to see the way back for that wisp of smoke.