The rise of nanometers

This launch vehicle is only a semi-finished product. Huang Xiuyuan visually inspected it and estimated that it was only about one-third complete.

Academician Wang Kan introduced him to some information about this launch vehicle: "Xiuyuan, this is the Chang 12 launch vehicle that was just designed. The design prototype was finalized in February this year. However, during the construction process, we encountered many problems."

"Length 12?"

Hearing the confusion in Huang Xiuyuan's tone, Wang Kan took a document from the side and handed it over: "These are some specific parameters."

Huang Xiuyuan took it and took a look and found that the design indicators of this new solid fuel launch vehicle were frighteningly high.

The overall weight reaches 824 tons, the low-Earth orbit payload is about 42.8 tons, the synchronous orbit payload is about 21.4 tons, and the lunar orbit payload is about 17.5 tons.

Perhaps compared to the giant Saturn V, the 12-meter-long payload is only about 40% of the opponent's.

But if you compare the payload ratios of the two, you will find that the low-Earth orbit payload ratio of Saturn V is only about 0.0388.

The future Falcon Heavy rocket will have a low-Earth orbit payload of 63.8 tons, with a payload ratio of about 0.0449.

It can be seen that China's launch vehicle design level needs to be further improved. The Falcon Heavy launch vehicle using a hydrogen-oxygen engine can increase the load ratio to 0.0449. This is indeed a very remarkable technology.

If Chang 12 can be further optimized and coupled with its own N20 high-energy fuel foundation, it is not impossible to increase the payload ratio of low-Earth orbit to 0.06.

After all, the specific impulse of N20 high-energy fuel is about 860, while the specific impulse of hydrogen-oxygen engine is only about 450.

Theoretically, the load ratio of a launch vehicle using N20 high-energy fuel as fuel should be about 1.91 times that of a hydrogen-oxygen engine, that is, around 0.0857.

However, Huang Xiuyuan did not dare to vouch for theoretical things.

The current payload ratio of 0.052 has set a new limit for human spacecraft. To improve it further, the engine materials, the overall design of the launch vehicle, and the control system all need to be further improved, which can only be done bit by bit.

Zhang Peicai on the side explained some problems in the design and manufacturing process of Chang 12:

"The current problems are mainly the engine's poor heat resistance and the combustion control of solid fuel."

"Heat resistance problem?" Huang Xiuyuan turned to the engine part and found that the 12-meter-long engine uses cermet materials specially developed by Aerospace Science and Industry. The cermet materials can withstand high temperatures of 3,000 to 4,000 degrees Celsius.

However, such high-temperature-resistant cermets cannot withstand the combustion temperature of the engine. This really caught the experts from the aerospace research institute off guard.

In current tests, due to the very high energy density of the N20 material, the engine tail flame temperature has reached a terrifying level of 5472 degrees Celsius.

Huang Xiuyuan asked a key question: "How can the Chang 11 engine solve this problem?"

"We used your company's silicon nano-coating and tungsten nano-powder..." Zhang Peicai explained.

After hearing the solution, Huang Xiuyuan knew how they solved it.

They used silicon nanoplating technology to coat a layer of silicon nanoparticles on the inner wall of the engine, and then used ion deposition to deposit a layer of tungsten nanoparticles. Repeating this process, a total of 142 layers of composite coating were used.

Although the silicon nano and tungsten nano layers can only withstand the extreme high temperature of 4874 degrees Celsius, the tungsten silicon nano composite layer has a very good characteristic, which is high temperature detachment.

When the ambient temperature exceeds 5,300 degrees Celsius, the tungsten-silicon composite layer will gradually liquefy and be ejected out of the engine by the engine exhaust flame. In this process, part of the heat inside the engine will be taken away and the heat transfer and heat accumulation of the high temperature to the engine base material will be delayed.

In this way, it is ensured that the engine will not be burned through the rocket body during the flight of the launch vehicle.

However, this method brings two disadvantages. One is that the weight of the engine is increased by 1.2 tons. After all, the weight of tungsten metal is very annoying; the other problem is that it treats the symptoms but not the root cause, which can only delay the time but cannot fundamentally solve the problem.

Huang Xiuyuan put down the document in his hand: "In other words, because the design index of the Chang 12 is more than three times that of the Chang 11, the engine cannot withstand the operating temperature for a long time?"

Zhang Peicai spread his hands helplessly: "Yes, if you increase the tungsten silicon layer inside the engine, it will further increase the weight of the engine. Moreover, the space inside the engine is limited, and it is impossible to stack the tungsten silicon layer without limit."

Faced with this fatal temperature, if it is a low-Earth orbit or medium-orbit launch vehicle like the Chang 11, it is relatively easy to handle.

However, the design tasks of the Chang 12 are mainly used for future lunar exploration projects, fire detection projects, etc., and they need to be in working condition for a long time. If it is changed back to liquid fuel, it seems that the gain outweighs the gain.

Patting his cheek, Huang Xiuyuan stared at the 12-long arrow body not far away and fell into deep thought. There will indeed be a lot of high-temperature resistant materials in the future.

The problem is that the materials are either currently unavailable with manufacturing technology; or they require rare elements and are extremely costly; or they are conceptual products from the laboratory and cannot be put into large-scale use at all.

Material issues are a headache no matter in which era.

The high energy density of N20 fuel is a double-edged sword. While it brings high-density energy, it also brings explosive power and ultra-high temperature.

After a while, Huang Xiuyuan woke up from his thinking: "I need some time to think."

"Xiuyuan, it doesn't matter. We still have time. I asked Guanghua to arrange a dormitory for you. The conditions are simple. Please bear with me." Zhang Peicai didn't pay much attention.

If Huang Xiuyuan could solve such a big problem as soon as he arrived, the thousands of people in the entire space port would be in despair.

Huang Xiuyuan smiled: "Just kidding, I'm not a spoiled young master."

The group continued to discuss the issue of Chang 12.

As he spoke, Zhang Peicai sighed: "Speaking of which, Chang 11 can be put into use smoothly, and I would like to thank you Suiren Company for the nano-mineral powder. Otherwise, there is no way to improve the performance and large-scale mass production of the cermet materials of the Science and Industry Group. .”

Huang Xiuyuan actually admires Aerospace Science and Industry. After all, he can develop rapidly by relying on his future accumulation of science and technology.

"The technical foundation of the Science and Technology Group is still good. At my Snail Industry, the new materials produced by powder metallurgy and the high-temperature resistant materials in the laboratory can only reach 3756 degrees Celsius."

"Let's take a look at the problem of how to control solid fuel combustion!" Academician Wang Kan asked his assistant to clear an area on the table nearby and give everyone a seat.

The combustion control problem of N20 fuel is also a huge trouble. Solid fuel has the disadvantage of solid fuel, which is that it cannot stop once it ignites. For missiles and the like, that is not a disadvantage, but for launch vehicles, it is It's a big problem.

This is also the reason why the second stage of the Chang 11 core has to use hydrogen-oxygen fuel, because once the solid fuel ignites, it cannot stop.

Outpost 1, which plans to go to the moon for exploration, uses solid fuel, and there is no way to carry out refined control. It can only rely on brute force to rush to the end.

If you cannot reach the designated orbit before the fuel is exhausted, you will end up making mistakes.

The Aerospace Research Institute has several research institutes that are engaged in precise combustion control of solid fuels, but they have achieved very few results.

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