"I still like the weather in the South China Sea, it seems to be always so warm."

Geng Bo, who had just returned to the Wenchang launch center from his father-in-law's house, pulled his collar and said.

At this time, the north was still in a snowy package.

However, the Wenchang launch center still looks like a hot summer.

Geng Bo, who had just gotten off the plane, felt extra comfortable.

"No wonder everyone wants to run to Hainan in winter."

In recent years, although Hainan has experienced a real estate bubble, the tourism industry has shown a vigorous development trend.

Especially in winter.

There is an endless stream of people coming from the north to spend the winter.

At least millions of people.

"How was this Spring Festival holiday, are you still happy?" Zhang Xingyang said.

"Hey, don't mention it."

Geng Bo said helplessly:

"Her parents have been complaining in our ears that the family next door is a year younger than her, and they have their grandchildren, when will they be able to hold them."

"I'm not annoyed anymore, so I came back so early."

It can be seen that the Spring Festival holiday is not particularly wonderful for some people.

This is the same whether you are married or not married.

"You come back so early, don't think about resting anymore, you're busy during this time."

Zhang Xingyang said after laughing for a while.

"Are rocket tests about to begin?"

Although Geng Bo did not specify which rocket.

But both knew which rocket the other was talking about.

In addition to heavy manned lunar rockets.

The institute has no other rocket development projects recently.

"Vibration behavior experiments will begin next week."

"This is the experimental project plan, you can take a look at it first."

Zhang Xingyang took out a thick booklet from his desk and handed it to the other party.

"Although we have now built some relatively accurate mathematical models, it is still very difficult to perfectly verify the situation of the rocket."

Geng Bo sighed with emotion, and began to look through the vibration characteristics test plan in his hand.

Vibration characterization tests are not particularly common in other fields.

It is only possible to see it on some devices with very complex dynamic characteristics of the overall structure.

After all, almost every time you experiment, you have to scrap some parts, and the cost is still very large.

No one wants to spend this money unless it is necessary.

"The current supercomputing, the computing power is still too weak, when can it rise by several orders of magnitude, maybe it can reach the level of calculation verification."

Zhang Xingyang also expressed a lot of his own views on this topic.

In fact, as rocket systems become more and more complex, the difficulty of calculations is also rising.

It's even faster than the computing power of a computer.

"For the longitudinal coupling vibration test provoked by the propellant in the closed system of the rocket body and the power plant, we want to directly do the real imitation experiment?"

Geng Bo didn't watch it very slowly, of course, because he skipped some less important content.

But the propellant longitudinal coupling vibration test, he is still very concerned.

Because the heavy launch vehicle uses a liquid propellant, that is, liquid oxygen kerosene.

And the number of engines is huge, and the thrust is huge.

So the liquid in the fuel storage tank is very large!

It can even be said that more than half of the mass of the rocket comes from fuel.

As a result, these fuels will shake during the launch and flight process for various reasons.

And shaking can cause a variety of vibration problems.

This is a question that all those who do the relevant work will pay attention to.

Because once the vibration problem is aggravated, it is likely to lead to very serious problems such as flight instability, abnormal propulsion system operation, and reduced control accuracy.

More likely, a direct lead to the failure of the rocket launch!

"Yes, you also know that the vibration behavior wants to be simulated according to a mathematical model.

With our current technological strength, it is simply impossible.

So we can only use the stupidest, but most practical way.

Just take out a rocket and do the experiment! ”

There's no way around it.

If the mathematical model can completely replace the experiment, then Zhang Xingyang will immediately cancel the rocket experiment.

But the current level of mathematics and computer science simply cannot do this.

It is difficult to establish a comprehensive realistic model based on the interaction between the natural frequency, mode shape, mode slope, damping coefficient, transfer function, etc. of each structural part.

The cost of rocket experiments was enormous.

You must know that the cost of a single YF-500 rocket engine alone has reached 8 million.

The overall cost of the rocket is in the hundreds of millions of dollars.

Although most of the parts can be recycled after the experiment.

But there are also parts that are bound to be destroyed in the process.

Therefore, the cost of a single experiment is about seventy or eighty million.

"Now in the world, except for us, no one seems to be conducting research on super-thrust rockets."

Geng Bo raised his head and thought about it and said.

"If we want to complete this part of the research and development work, we really don't have anything to learn from, we can only rely on ourselves."

There are not many countries in history that have completed launch vehicles with a thrust of more than 1,000 tons.

can be counted, there are only Saturn V and Energy.

But Saturn V, now you ask NASA to make another one, it's impossible.

They're still on the not-so-pathed side of the space shuttle.

As for the Energia, it was directly forgotten in the Baikonur Space Center.

Therefore, for us, there is really only one way to go on our own.

The Wenchang launch center is different from other launch centers in China.

In the early stage of construction, there was a design for the development of aerospace characteristic tourism.

So, the Wenchang launch center has a group that other launch centers can't see.

Visitor.

Fortunately, the mobile Internet is not particularly developed in these years.

Otherwise, there will definitely be quite a few people who will broadcast live while the rocket is being launched.

The general rocket vibration characteristics test is carried out in the vibration tower.

However, their heavy launch vehicles, there is no way to use vibration towers.

Without him, the heavy launch vehicle is simply too big.

The vibration tower simply won't fit!

This is also an important reason why this experiment will burn money like never before.

On the modified test bench, the heavy rocket is undergoing final checks.

Although this is only an experiment on the vibration characteristics of the rocket, everyone still treats it as a normal launch job.

"The shaker is in place and ready to work." Geng Bo said.

The purpose of the exciter is to make the parts of the rocket produce the desired vibration, so as to achieve the effect of simulation experiments.

"All locations, already in place?"

Zhang Xingyang asked, looking at the rocket comparable to a skyscraper at the scene.

"All the platforms around the rocket have been installed, a total of 48 shakers."

Heavy launch vehicles are very large, so they need to install more shakers.

The average forehead rocket, almost thirty more is completely sufficient.

"Now that the installation is complete, let's start the trial as soon as possible!"

Zhang Xingyang said after glancing at his watch.

Heavy launch vehicles are not elastically suspended in the air, as is the case with traditional vibration tests.

Instead, the entire rocket is erected on top of the oil-gas support system to meet the boundary conditions of the rocket during flight.

The engineers, who accompanied the inspection, left the rocket platform.

The experiment officially began.

The exciter still excites the structural parts incessantly.

At the same time, a huge liquid filling system was also working.

Every second, tons of liquid are expelled from the rocket's fuel tank.

This is to simulate the change of the internal propellant stock of the rocket at different times during the flight of the rocket.

A variety of measuring devices began to collect data from the rocket.

And the data is aggregated into the control room.

The first thing to do is to carry out vibration characteristics experiments, that is, to determine the vibration characteristics of the rocket itself.

This was followed by the rocket's ability to adapt to the vibrating environment, also known as the vibrating environment experiment.

Neither experiment itself is very long.

After all, the rocket's completion time is only a few minutes.

The working time of the first-stage rocket is generally more than 100 seconds.

However, it took nearly a week to analyze the data generated.

"The report of the vibration characteristic test and the environmental test is out."

Geng Bo walked into the office quickly, and handed Zhang Xingyang the two reports in his hand that still smelled of ink.

Zhang Xingyang didn't look at the report directly, pointed to his computer screen and said:

"I've seen the electronic report."

"Nothing different, right?"

Because he was worried that they would find out something different later, Zhang Xingyang immediately said.

"It's the same with the electronic version."

Geng Bo first answered the question, and then said with some emotion:

"The vibration characteristics of the heavy launch vehicle seem to be different from all our previous rockets."

"This is also an inevitable result, the heavy-duty launch vehicle, whether it is the engine thrust or the structure, is much larger than the original."

Zhang Xingyang said affirmatively:

"This result is not too different from my previous prediction, except for a slight deviation in the vibration amplitude of the shell, it is basically the same."

Geng Bo smiled and said:

"Even if there is a deviation, for us, such an error is still within the allowable range."

Now that Zhang Xingyang had already read the electronic report, Geng Bo didn't tell him too much about the report.

Instead, he asked about the next experimental plan for the heavy launch vehicle.

"When will the next experiment start?"

There are a lot of experiments that need to be carried out before the rocket can actually be tested in flight.

Including vibration characteristics test, ground test test, transportation test, wind load test, docking and coordination test, flight test and so on.

Follow the general experimental procedure.

The next experiment that should be conducted should be a ground test car.

The ground test is the only experiment that really needs to carry out the ignition of the rocket engine after the rocket is assembled.

It is the final test of the propulsion system on the ground.

After that, the propulsion system is tested in the sky.

"The test bench is almost ready, and the final equipment commissioning is underway." Zhang Xingyang said after flipping through the work log on the table.

"If there are no accidents, then we will be able to conduct a local interview next Tuesday."

Compared with the vibration test, the consumption of the ground test vehicle is greater.

The vibration test also simulated the process of rocket fuel outflow.

But after all, there is no real consumption of fuel.

Ground test vehicles need to burn hundreds of tons of liquid oxygen and kerosene.

In order to test the car this time, the research institute bought at least 1,000 tons of rocket kerosene and liquid oxygen.

Although the kerosene production base in Yulin is now able to produce high-quality rocket kerosene.

But the price is still relatively high.

For these fuels alone, the institute spent tens of millions.

With a thrust of more than 6,000 tons, how strong can it be?

Let's put it this way, if you use this power to push a small hill, you can push it!

This is a truly mountain-destroying force.

The power of immortals in the mythology of the ancients is nothing more than that.

On the test bench, the rocket itself, which is more than 100 meters high, is like a hill.

The floor of the test bench is specially reinforced.

It is difficult for ordinary ground to withstand the destruction of such high temperature and high pressure gas.

Most of the general construction cement grades are C30 or C40.

The cement mark of the test bench is C120.

It is enough to withstand a high-explosive attack head-on, and even armor-piercing shells want to penetrate, it is very difficult.

Only such a solid ground.

to be able to support the huge power of the rocket.

"Heavy launch vehicle, the first ground test car, start!"

Zhang Xingyang gave an order.

At the bottom of the rocket, after the explosion of TNT, a large amount of liquid oxygen kerosene ignited in the combustion chamber.

Unleash a huge amount of high-heat gas!

Renders the ground a golden yellow.

Then with a rapidly climbing thrust, it gradually turns pale blue.

The flame is directed to the side through the deflector groove around the test stand.

Creates a fire dragon tens of meters long.

With a large amount of white smoke, it seems like a dragon swimming in it.

The most shocking and powerful thing to do.

Or the earthquake that comes when the rocket starts.

The experimental control center is not very close to the rocket test bench.

It's about a few hundred meters away.

But even at such a distance.

You can still feel the shaking of the earth in the control center!

"Good guys, it feels like there's a shell exploding in the distance."

Even Geng Bo couldn't help but sigh at the intensity of the tremor.

The rocket test time was not very long.

But within a few hundred seconds.

All the liquid oxygen kerosene in the 12 large fuel storage tanks was consumed.

That's more than 2,000 tons in total!

It can be seen that such a big guy.

It's not just the thrust that is scary.

The consumption is also quite impressive.

After the test run was completed, Zhang Xingyang couldn't help but say:

"When everyone buys a car, they like to say that XX cars are oil tigers."

"It's still too little knowledge."

"We're big guys, we're the real oil tigers!"

"The amount of fuel consumed for a launch is estimated to be enough for thousands of vehicles to drive for a year!" (End of chapter)