Chapter 175: The formula I derived is different from the one in the book
The problem of rocket engine cooling seems simple, but the things involved are quite complicated.
The internal temperature of a rocket's liquid engine can reach around 3500K.
In addition to high temperature, there is also a high-pressure environment inside the rocket's liquid engine.
The general thrust chamber structure is difficult to withstand such a harsh environment.
Therefore, various thermal protection measures need to be introduced in the thrust chamber of the rocket engine .
How to quickly cool down the engine is a very important issue.
For liquid engines, the more commonly used cooling methods include regenerative cooling, liquid film cooling, radiation cooling, etc.
If it is a high-thrust liquid rocket engine, liquid film cooling is generally used simultaneously with regenerative cooling.
For high-altitude orbit attitude control engines, liquid film cooling is the main cooling method.
Therefore, the liquid film cooling system is a problem that Xu You must solve.
Xu You entered a deep learning state, increased the efficiency of his brain to the highest level, and began a very fast thinking mode.
Soon, Xu You sorted out his thoughts and determined the main problem he currently needed to solve.
Although liquid film cooling is now a technology that is widely used in rocket liquid engines.
But it also has its own problems and limitations.
When the coolant is injected into the inner wall of the thrust chamber, the mixing ratio in the area near the wall of the thrust chamber will seriously deviate from the optimal mixing ratio.
As a result, part of the propellant will not be able to effectively participate in combustion, resulting in loss of thrust chamber performance.
"Let's construct a physical model first and calculate the key data."
Since Xu You decided to redesign it himself, he certainly couldn't just copy it completely based on previous experience.
Xu You needs to give his own unique understanding while referring to historical experience.
Xu You needs to calculate all the key data himself to ensure the most accurate conclusion.
The first thing Xu You calculated was the thickness of the liquid film when the jet hits the wall, as well as the flow distribution data.
On this problem, Xu You needs to construct a physical model himself first and then perform calculations.
“It feels a bit like doing a physics competition question.” Xu You sighed.
Xu You had to admit that his experience of participating in the physics competition was indeed very meaningful.
Not only did it help me get admitted to Jilin University, but the knowledge gained from physics competitions also helped me in my scientific research work, as I learned many methods and techniques for solving practical problems.
Based on the conditions, Xu You established a flat liquid film thickness distribution model on a draft paper, marked the symbols used, and established the corresponding coordinate system.
Once the model is built, the only problem left is column calculation.
Soon, Xu You derived two functions related to the flow azimuth angle φ.
Through comparison, Xu You found that his deduction results in this part were consistent with those of other researchers.
This feeling is like checking the answers after finishing a question and finding that the results are consistent with the standard answers.
For Xu You, this is a very normal thing.
But in Xu You's heart, he was secretly hoping that his conclusions would be somewhat different from those of his predecessors.
After all, there is no such thing as a "standard answer" when it comes to scientific research.
Only by surpassing the conclusions of predecessors can one make a breakthrough in this direction.
Of course, the research results in books and papers are not so easy to overturn.
After some calculations, Xu You found that all the data and formulas were consistent with the above.
"Hmm? Wait a minute!"
At this time, Xu You suddenly discovered.
Above the theoretical expression of liquid film flow distribution.
The formula I derived was actually somewhat different from the formula in the data.
Xu You did not feel excited immediately, but first checked his derivation process to see if there were any problems.
After all, no matter what level of academic master you are, when the result you get is different from the standard answer, it is impossible to immediately think that the standard answer is wrong.
No matter how confident you are in yourself, you still need to confirm it carefully.
"There is indeed nothing wrong with my deduction."
Xu You carefully checked his derivation process several times and confirmed that there were no problems.
But when Xu You analyzed the formula derivation process in the data, there was no problem either .
"It turns out that it's because I took an extra jet parameter into consideration."
This jet parameter does not appear in the original formula.
Xu You felt that this jet parameter was not meaningless.
It’s just that the impact of this jet parameter may be too small and is directly ignored.
Xu You did not try to determine how much impact this jet parameter would have on the results, or whether it should be ignored.
But Xu You remembered the error problem that occurred when he helped Wang Xiangwu solve the problem of quantum phase change last time.
It is just an approximate process with an error so small that it can be ignored, but after being amplified, it can also have a significant impact on the result.
Therefore, Xu You decided to reserve his opinion on this issue for the time being.
After that, Xu You spent half a day to complete the analysis of the entire problem, including the derivation of various formulas.
"Sure enough, in the subsequent data processing, there is also an amplification process!"
After careful thinking and analysis, Xu You noticed that this problem was similar to Wang Xiangwu's last experimental topic.
If this jet parameter is not neglected, the resulting data will be more accurate.
And this may be the key to designing a new liquid film cooling system.
The next step is to simulate the entire cooling process through software simulation.
Xu You once again felt the importance of informatics.
Although there are certainly certain errors between the results of software simulation and actual experiments.
But as long as the simulation accuracy is high enough, this is definitely a much more efficient method than actual experiments.
Through software simulation, Xu You completely simulated the processes including the formation of liquid film, entrainment of mainstream, liquid film cooling in the thrust chamber, and the impact of liquid film cooling on engine performance.
In this way, Xu You can easily check what impact the changes in various parameters will have on the results of each process.
Based on the feedback from various data, Xu You was thinking about how to design a new thrust chamber cooling structure.
Unconsciously, Xu You once again entered that magical flow state.
In the flow state, Xu You's attention is more focused and his brain state reaches the highest level.
Gradually, Xu You finally pieced together the scattered chains in his mind.
