Chapter 458: Coaxial jet injection system!

Luo Jia explained to the general on the phone that the ultimate test of the space plan is cost-effectiveness, to see who can deliver the goods to space at a lower price.
Russia's RD-171 engine, at the same time that thrust created history, also reached a record high cost, which reflects the characteristics of Mao Zi's great joy.
Luo Jia is a science and technology man, a devoted believer in dataism. Under his leadership, Xingchen Technology ’s rockets are designed exactly according to requirements. As much thrust as needed, the rocket engine is designed.
Besides, Luo Jia has the habit of hiding everything, and I am afraid this time is no exception. No one can guarantee that the design of the star rocket engine does not hide amazing secrets.
For Luo Jia, Russia's Yenisei Super Heavy Rocket has only one function, that is, cannon fodder, which attracts real opponents to this space race, thereby quickly consuming the opponent's strength.
...
A subsidiary of Xingchen Technology, Rocket Lab.
Luo Jia has been in the Rocket Lab for several months, and all plans are advancing at an extremely fast speed. It seems that everything is moving in the right direction. The only exception is the injection combustion system.
For a few days, the Rocket Lab was full of sorrow and fog. Everyone seemed to be under great pressure. Luo Jia's office was covered with a white board with secret numbness, extremely complicated formulas and numbers.
Except for taking a bath and going to the toilet, Luo Jia almost never leaves the office. He is like a high-speed machine, crazy and continuous high-intensity work.
His state made everyone in the laboratory feel nervous. After all, Luo Jia was the leader of the tough guy sky group. If he had a problem, it would be a loss that the entire company and even Huaxia could not make up for.
So they talked about it, and invited Enron, the vice president, to hope that Enron could persuade Luo Jia, but they were surprised to find that Enron, like Luo Jia, was also a lunatic!
For forty-eight hours, the two stayed in the office, discussing and analyzing constantly. They are rare geniuses in the world, and their brains are thinking at an extremely fast speed.
Everyone heard Enran and Luo Jia arguing in the office, they were all stupid. The two bounced back and forth between different disciplines. They were still discussing thermodynamics, and they jumped to aerodynamics in the blink of an eye.
In short, it means to spend their brains. Following their thinking for a few minutes is okay. After fifteen minutes, the brain will become chaotic. After more than half an hour, the headache will rupture and reach one hour. That is and it will drive people crazy.
As a result, things changed from Luo Jia's own life, and he and Enran ...
Enron stayed at the Rocket Lab, and the heads of the major project teams in the hardware department stopped working, and complained to colleagues at the Rocket Lab. Why did you ask Enron to persuade Luo Jia? People who are familiar with Mr. Luo know that he never listens to persuasion.
In short, the colleagues of Rocket Lab finally realized that Luo Jia and Enran can stand on the top of the company for a reason. They are not only smarter than most people, but also desperately hard!
Can the two bosses work without sleep, is the injection combustion system really important for a rocket?
The answer is yes.
With the continuous upgrading of rocket fuel, keeping the injection system stable is becoming more and more difficult.
Not to mention the latest generation of liquid oxygen methane engine, which is the previous generation of liquid oxygen liquid hydrogen engine, has also brought huge troubles to scientists. Luo Jia intends to save costs and allow the engine to be reused unlimited times. In this way, for the The requirements for durability and stability are even higher.
"Next you continue to improve your thinking, I'm going back, after all, the hardware department is also busy flying, I have no time to accompany you for a long time." Enron scratched the hair that has long become a chicken nest, said to Luo Jia.
"Understand. Don't just focus on your work. Spend more time with your wife and children when you have time. Don't worry about not knowing you as a father at the end." Luo Jia teased.
"Come on." Enron waved his hands in disapproval. "You bachelor, on the contrary, taught me how to be a dad? When will you have a wife and children?"
What does this have to do with being single?
The single dog he meows really has no human rights. He clearly speaks good words, but no one is willing to listen.
Luo Jia shook her head and muttered in her heart.
...
The reason was unclear, and in-depth discussions with Enron led Luo Jia to change his mind again. He wiped all the whiteboards in the office and started from scratch. Soon, the numbers and formulas on the blank whiteboards became dense again.
He is calculating TRinstability, which is Taylor instability. The interface between two fluids with different densities is unstable. In a gravity field, instability may occur when a heavier fluid is above a lighter fluid.
When the rocket engine jet is injected, the cavitation phenomenon of the propellant in the pipeline is caused by the acceleration effect, and the bubble after cavitation will induce the compressible Taylor instability.
In addition, the high-speed flow of propellant in the centrifugal pump and pipeline will also cause cavitation. The bubbles generated by cavitation will release the pressure at the moment of jet ejection. If the centrifugal pump is cavitated in the working state, it will be fatal It must be completely eliminated.
In addition to Taylor instability, the rocket ejector must also consider RMinstability, which is turbulent instability.
Regardless of the tangential velocity gradient or the normal acceleration, perturbation waves are generated at the fluid interface in nature. A small number of perturbation waves propagate at supersonic speed and become shock waves. When the fluid interface with the initial perturbation is impacted by the shock wave, the interface peaks The troughs will produce velocity differences and promote the evolution of disturbances, which will eventually cause turbulence and bring huge hidden dangers.
In short, the rocket engine is very difficult to design, and a low-cost engine with stable performance that is ridiculous ~ EbookFREE.me ~ and can be used repeatedly for a long time, the design difficulty is not a great problem, and It's difficult!
For example, during the fuel injection process of a rocket engine, the atomizing medium is regenerated and cooled through the nozzle wall, and then becomes a gas and then is ejected from the nozzle. At this time, the injection speed often interacts with the sound velocity and velocity oscillation, which inevitably brings shock waves. It may even be superimposed with the interference caused by the expansion wave.
For another example, in free space, shock waves and pressure disturbances caused by combustion will diffuse freely into the environment. In a closed sound cavity such as a combustion chamber, shock waves and pressure waves will encounter refraction in the engine wall. This often results in unstable high frequency combustion.
Anyway, there are too many factors that can cause instability. The aerospace industry has assembled the world's smartest brain, but disasters still occur one after another. From this, we can see that the rocket thing is not the hardest thing to build, but to really do it. Stability and security, even the most experienced in North America and Russia, cannot.
The numbers and formulas became more and more complicated, and gradually became simpler in the following days. In the end, there was only a large white board in the office. It was written with Luo Jia's results obtained in the past ten days. The name of the result. Called.
Coaxial jet injection system!