Chapter 316 (2/2)
”The maximum service temperature of stainless steel is about 1000 degrees. High temperature alloys used in aerospace engines usually can't exceed 1500 degrees. Cermet will be higher. But I'm not sure its inherent properties are suitable for blade materials...”
”If we just look at the melting point, hafnium alloy, graphite, diamond, tungsten and other materials can indeed exceed 3000 degrees, but they are too expensive and rare, or they are not competent for the special tasks of engines due to their plasticity and brittleness...”
”So, I can't think of a material that can be used in space engines on a large scale and can withstand the high temperature of 3000 degrees...”Zhu Mingyue heard the last, unconsciously began to Baji mouth.
”Chemistry and materials science are good, too.”
”Ah...” Li Zheng waved his hand modestly, ”it's just that I participated in a few small competitions I can't even think of such a material... ”
”It's right not to think of it. I can't think of it.” Zhu Mingyue said with a smile, ”this kind of perfect material only exists in theory. The materials from all over the world may not be able to make a rocket. Most of the alloys we use on a large scale have working temperatures within 1500 degrees, which is mainly achieved by special coating and propellant flow.”
”However, in the turbine pump blades, these technologies are greatly limited.”
”In short, this part cannot be cooled at this stage, and the upper temperature limit of the precombustion chamber is only 1300 degrees.”
”But the temperature of full combustion of liquid hydrogen and liquid oxygen is 3000 degrees.”
”What to do?”
Lin Qijing, who has been silent for a long time, suddenly got excited: ”not enough combustion Excessive combustion? ”
”It's true that by injecting excess hydrogen, or oxygen, into the precombustion chamber, we're creating inadequate combustion, keeping the internal temperature within 1300 degrees.” Zhu Mingyue turned his head again and was attracted to Lin's side. ”So the question comes again, is it hydrogen excess or oxygen excess?”
”It must be hydrogen.” Lin Qijing nodded vigorously, ”high temperature pure oxygen will lead to severe oxidation and corrosion, who can withstand it?”
”Very, very good.” Zhu Mingyue wanted to clap his hands. ”If it wasn't for Mr. Shen's guidance, it was all up to you. I really haven't seen your brain...”
Before he finished speaking, he quickly said to Li Zheng, ”that You're smart, too. There's no other meaning... ”
”It's OK. Go on...” Li Zheng's face is extremely plain, ”used to.”
So is Lin Qijing, and so is guijianfeng
Facing this kind of brain circuit which is not human, Li Zheng has been used to it for a long time
”Well, go on.” Zhu Mingyue coughed his throat and said, ”such excessive hydrogen combustion will inevitably produce waste gas, so we need to set up an exhaust system...”
”In the first zero fault model, it was the exhaust system that went wrong.”
”Simply put, the exhaust port is broken, resulting in air flow blockage.”
”In a short period of time, the air flow that propels the turbopump suddenly decreases sharply, and then the fuel cannot be injected into the combustion chamber.”
”The combustion stops quickly and the engine stops.”
”That's the complete recurrence of the fault.”
”Such a failure has never occurred in the previous test run of more than 30000 seconds.”
”We believe that it was Huang er who encountered a special resonance in the extreme environment during his ascent, which led to the failure of the exhaust system.”
”This exhaust design is time tested and there has never been a precedent before.”
”At that time, we thought it was bad luck and the boat capsized in the gutter.”
”After identifying the fault point, we raced against the clock to strengthen the entire exhaust system to withstand more severe conditions than in the recurrence of the fault, and then confidently delivered the new version of the engine to the test site.”
”In the first two routine tests, the engine still performed well.”
”You've seen the results of the third extreme environment test run.”
”There is nothing wrong with the strengthened exhaust system. Instead, the shafting is broken.”
”The shaft system is the core of the core. The fracture here is 10 times more serious and 10 times more complex than the exhaust fault. I'm afraid it can't be solved by repairing. Many people think that the process of finding and repairing faults is longer and harder than even redesigning an engine. ”
”To make an inappropriate analogy, we first found a small leak in the dam and then filled it with cement to plug it.”
”The next day, the whole dam collapsed.”
”It turns out that what we're blocking is not a leak, but an ant nest.”
”The Bank of thousands of miles has already been densely penetrated by ant nests.”
”This is the seriousness of the problem at this stage.”
At the end, Zhu Mingyue nodded.
”Therefore, I personally do not object to the 927 project.”
”When chief engineer Zhang and academician Zhang fall down, I have the responsibility to take over the baton.”
”But in my experience, such serious defects are very difficult to solve in a short period of time. In order not to affect the follow-up space strategy of the country, 927 is also a painful choice for big leaders, a choice that has no choice.”
”But it doesn't affect our determination to do our best.”
”Know that you can't do it and do it.”
”Know it's hard to do it, and try to do it.”
”Since its establishment, the 17 research institutes have been carrying heavy loads.”
Zhu Mingyue got up and raised his right arm.
”Li Zheng, Lin yuejing.”
”Welcome to China Aerospace Power Research Institute.”Li Zheng clasped his hands with Zhu Mingyue and shook them vigorously: ”for it! Try to do it
When Lin qiojing shook hands, he was calm and asked thoughtfully, ”I don't understand one point...”
Zhu Mingyue nodded with interest: ”please say so.”
”Why do we have to exhaust?” Lin Qijing frowned and kneaded his chin. ”There is still a lot of excessive hydrogen in the so-called exhaust gas of the pre combustion chamber. Why waste it? Is it not good to inject it into the combustion chamber? So the overall fuel efficiency of the rocket is not higher? ”
Zhu Mingyue a listen to stare: ”your mother really did not tell you?”
”No...”
”Then you can take over her in a few years...” Zhu Mingyue repeatedly nodded his head and explained, ”of course, the design you mentioned exists, and it is the optimal design. Our yf-100 kerosene engine adopts this design, which can not only fully burn, but also double the pressure in the combustion chamber. However, as for the hydrogen oxygen engine, it has higher requirements on structure, parts, pumps and materials, so we can not challenge the highest difficulty at the first step. Therefore, we adopt the gas generator cycle which needs exhaust. ”
”Well...” Lin Yujing breathed a sigh of relief, ”it's smooth...”
”I don't understand Secretary Zhao's boasting about you Now I accept it completely. ” Zhu Mingyue pursed his mouth and nodded, ”18 years old, my God The education system has been working for so many years, which can be regarded as the cultivation of people like you. ”
As soon as Zhu Mingyue finished, he quickly turned to Li Zheng and said, ”of course, there are still others like you It's you. I was wrong... ”
”It's OK. I'm used to it. I'm used to it...”
”Well, in view of your level, the test team should not go.” Zhu Mingyue then arranged, ”a temporary fault investigation team will be set up immediately. There is a person who is absolutely enough to be your teacher to act as the team leader. You can directly follow him.”
Just as he was saying that, behind him came a unique and intensive knock on the door.
Dong Dong, Dong Dong Dong, Dong Dong Dong, Dong Dong Dong
For this knock, Li Zheng still has some impression that it is a prime number sequence.
However, his face was stiff, and he had a bad premonition.
”In.” Zhu Mingyue road.
Immediately, an old handsome face poked in: ”wait for a long time, insert a team?”
Zhu Mingyue was overjoyed and rushed to meet the people himself. He took the hand of the commander-in-chief Du Songtao: ”this is chief engineer Du Songtao. NASA is eager for the top experts. He is impatient to ask for the rocket and so on. He specially asks for the support of our 17 research institutes. From now on, you will follow him.”
”Ah...”
”Well...”
Li Zheng and Lin yuejing were happy.
All of a sudden it's not good.
There's a sense of spore man spies breaking into human beings, parasite or something.
Du Songtao, however, was quite happy. When he entered the room, he made a glass of water by himself. He walked up to them, drank the water and picked his eyebrows: ”this is not a coincidence.”
Coincidentally your mother, this is obviously the plot of spore man!
Looking at their strong hostility, Zhu Mingyue asked: ”know?”
”Not familiar.”
”Not familiar...”
”Better to know.” Zhu Mingyue said, ”then you two go out and wait. I'll talk to Songtao about a few things.”
They went out of the office with their heads down.
Then I ran into the big brother with long inch head in front of them.
The elder brother stood at the same place in confusion: ”an hour I worked hard in line And to you Why did you jump in the queue Can't you talk to me about it... ”
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