On the other side, Chengdu.
Chen Nian sat in the office, looking at the thick pile of draft paper in front of him with a frown.
As early as a few days ago, he had entered normal working mode. Now, in addition to his fixed daily study schedule, he spends all his time on the theoretical analysis of the two-stage counter-rotating lift fan.
It must be said that this is an extremely complex task.
Although the F-35's body design and center of gravity data have been obtained, it is still difficult to rely on these things to deduce the precise design data of the fan arranged behind the seat.
Therefore, there is only one thing he can do:
Reference similar aircraft as much as possible and look for clues from them.
During this period, Chen Nian consulted a large amount of information, but there was very little that was actually useful.
In fact, the world's first vertical take-off and landing fighter aircraft appeared in 1950, but the "vertical take-off and landing" method of that thing directly made the engine thrust greater than the power of the body, allowing the aircraft to take off in an upright position. For Chen Nian, The question is not helpful.
Similarly, the second-generation STOVL with additional take-off and landing engines and the third-generation STOVL with tilting engine are also useless, with completely different design logic.
The only useful thing is the fourth-generation dual-mode STOVL, but this thing is only available on the F-35.
Chen Nian felt as if he was trapped in an endless loop.
After a busy week, he made no progress in deducing 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 goal is set to two days later is because according to his current source point growth rate, it will basically be possible to accumulate enough source points to analyze the core technology of the two-stage counter-rotating lift fan in about 10 days.
If you continue to waste it, you will not have enough time to study, which is equivalent to a net loss of 0.18 points per day.
Thinking of this, Chen Nian couldn't help but sigh.
He reluctantly pushed away the messy papers, stood up and walked out the door, wanting to take a breath of fresh air.
Unexpectedly, as soon as he went out, he bumped into Yang Wei who happened to be looking for him.
"Chen Yunyong has done it!"
Chen Nian was overjoyed when he heard what he said.
"Done? How? When will it be done?"
"Replacing it with the EC-130H. Speaking of which, it's all your fault for getting to the root of this matter."
"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 aircraft."
"What is Haohao's main field?"
Chen Nian continued to ask.
"They have everything, including people who work on finite elements, people who work on aerospace engineering, and people who specialize in materials. A small number of them were brought back from the United States by Chen Yunyong."
"Those people basically worked in private companies before, and they themselves had a certain willingness to return to China. After review, they were allowed to come back."
"By the way, you don't mind this, right?"
Yang Wei asked slightly worriedly.
In fact, for him personally, his origin and past experience are not too important.
As long as it can pass the review and meet relevant confidentiality requirements, he believes that some overseas service experience can actually be relaxed appropriately.
After all, when they chose to stay there, they did not want to betray, but were simply attracted by better conditions.
This is a very real problem.
After finally learning it, who doesn’t want to be able to sell his skills at a good price?
Money is the courage of heroes. When everyone is generally in difficulty, the pursuit of money is not a heinous matter.
What's more, when it comes to treating talents, in some cases in the past, the respect we gave them was not enough. This is a real issue that needs reflection.
Now that the higher-ups have begun to consciously improve remuneration to attract talents, it is even more important to ignore past grudges and show our sincerity.
This also has the chill of buying horse bones for thousands of dollars.
Of course, that's what he thinks, not necessarily everyone thinks that way.
Objectively speaking, there are still many people who are biased. 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 awesome. He makes a lot of money with his beautiful sword, and he can actually kidnap him back."
"Huh, everyone still has some ideals, and it's not necessarily money worship that comes first."
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 are really relying on their passion to survive.
"How are you preparing? Is there any progress?"
"No."
Chen Nian answered without any hesitation.
"Do we need to apply for foreign aid? We can talk to Russia. They have similar research."
"No need for now, just give me a few more days."
"Don't worry, Xiao Nian, the progress of this kind of project cannot be measured by the sky."
Yang Wei said dumbfounded.
Good guy, I still wanted to comfort him and tell him that it didn't matter even if the output was delayed two months, but what did they say?
Give it a few more days.
This is no longer a conversation on the same channel.
The two chatted for a few more words, and Chen Nian walked out of the room to relax. When he came back, his thinking was much clearer.
He spread out the scratch paper on his desk, re-entered the state, and planned to start the deduction from the beginning.
According to the take-off quality of the F-35B aircraft, Male Horse Company adjusted the entire aircraft layout for the lift required for the aircraft to take off. This 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 to take off vertically should be about 18.14 tons. However, this part of the thrust is not entirely provided by the lift fan. Among them, the vector nozzle and attitude adjustment nozzle It also needs to bear 55% of the lift.
In other words, the thrust provided by the lift fan should be about 8.16 tons.
In order to generate this part of the lift, the lift fan not only needs to have a relatively large pressure difference, but also needs to pass enough flow.
Then, the diameter of the lift fan must be strictly planned.
This part is the hardest.
Chen Nian frowned and carefully recalled the data he had seen in the previous life. He also referred to the thrust of conventional thrust fans, combined with the overall body size of the F-35, and finally determined a number:
The lift fan diameter 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 about 210kg/s.
"Suppose 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 the boost ratio is π*”
".q(λ) is the dense flow function, from which we can deduce q(λ), Ma1, p1, T1 on the inlet cross section"
"The lift fan inlet airflow velocity V1 is determined by the continuity equation."
"Compressor efficiency formula is available"
"The final lift expression is"
Chen Nian recited a series of calculation formulas in his mind, and his movements became smoother and smoother.
At this moment, his brain was operating at full capacity, and even beads of sweat began to form on his forehead.
He was like a supercomputer, frantically calling up knowledge from two time spaces and two worlds, trying to fuse them together to arrive at the final result.
"So, in order to further accelerate the air, the lift fan outlet is a tapered nozzle, and the constraint conditions can be given: Ma3<1, A3<A1"
"In addition, considering the ground effect during takeoff and landing, there is a lift loss in the lift fan, and the general loss rate should be around 50%."
"Traversed the changes in the exit cross-sectional area A3, lift F, and pressure ratio π* with λ within the range of the speed factor λ∈[0, 1]"
2.165!
With a total pressure ratio of 2.165, the generated lift can take into account both the target lift and the lift required after ground effect!
Chen Nian dropped the 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 calculation for the first time, a credible result was obtained!
Moreover, according to my own calculations, if tolerances are taken into account, it is relatively safe to set the total pressure ratio of the lift fan to 2.2 to 2.4. This can ensure that even if there are differences in the aerodynamic layout of the J-20B and F-35B, the 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 important.
On the other side of the sea, it was already late at night.
Chen Yunyong sat in front of his desk. On the desk was a pile of draft paper spread out that was almost identical to Chen Nian's.
The problem he is trying to solve is the same as Chen Nian's, which is to calculate the appropriate total pressure ratio required for a 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.
Over the past five years, he tried every means to obtain as many resources as possible within his capabilities. At the same time, he also asked many friends in the same industry for help, but the progress was always slow.
Just as Dick told him at the time, his research was too rudimentary.
But why primary?
In the final analysis, the most critical "1" for startup is still missing.
But recently, he suddenly felt inspired.
Maybe my initial direction was wrong.
In particular, it is difficult to obtain correct results by reasoning from the perspective of pure data.
What is really effective is physical experiments.
From the perspective of aerodynamic design, it is deduced how large a fan should be used to meet the requirements of the body layout.
In this way, the data range will be greatly reduced, and the difficulty of calculation will be reduced accordingly.
——
This didn't seem to be an uncommon idea, and it wasn't like he hadn't thought of it before.
The key is that he didn't have any information related to the F-35B before, he only had a few words, which was of no use.
But now, after finalizing the time to return to China, special staff passed the information to him, so his research began to advance by leaps and bounds.
It only took him less than two weeks to clarify his calculation ideas.
And today, the first result was calculated!
2.21.
Under this pressure difference ratio, J-20 will achieve perfect adaptation with the STOVL system, and the theoretical problem of the two-stage counter-rotating lift fan will also be completely solved.
Chen Yunyong's face showed an excited look. He wanted to shout a few times to vent the turbulent emotions in his heart.
But he knew that in his current situation, even celebrating was a luxury.
So, he had to put away 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 irrepressible 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 looked at each other silently. After a long time, Liu Huixia asked:
"To burn it?"
"Yes, burn it. Everything is already in my mind. We can't leave any clue to those white ghosts."
"Okay, let me help you!"
With that said, Liu Huixia turned around and went to the kitchen to get a lighter. Then she hesitated for a moment and brought the iron pot for cooking into the bathroom.
"Put them inside and burn them one by one to avoid triggering the smoke alarm."
"I know."
Chen Yunyong lit the first page of manuscript paper, and bright yellow flames rose, reflecting the mixed emotions 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 or 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, just seize the day."
Hearing his words, Liu Huixia smiled softly.
She threw a piece of manuscript paper into the pot, and then said comfortingly:
"You see, you are still pessimistic at heart."
"In fact, the development of science and technology is leapfrog. Maybe one day, when you don't expect it, the problem will be suddenly solved?"
"Just like when you solve the fan problem, isn't it the same process?"
"No, it's different."
"This problem can be solved only after five years of accumulation. But, how many five years do we have?"
"Your five years, plus someone else's five years, will create different results."
Liu Huixia continued.
"Unless you really don't believe in them or that land at all."
"That's not true."
Chen Yunyong shook his head gently, hesitated for a moment, and then said:
"I just regret it. If I hadn't chosen it at that time, maybe everything would have been different."
"it does not matter."
"Every road has different twists and turns - think on the bright side, maybe someone has taken your place in the country?"
Speaking of this, Liu Huixia showed a sly smile on her face.
"Perhaps the results you are making now have actually been made by someone?"
"When the time comes, 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 green smoke gradually drifted away.
This wisp of smoke penetrated the bathroom window, and with the wind, it floated higher and farther into the sky.
Chen Yunyong watched this scene with some trance.
At this moment, he seemed to be able to see the return path of the wisp of smoke.
(End of chapter)
