Chapter 1968 Requests Not to Participate
“Therefore, when designing a ship, the cavitation effect is an issue that must be considered. Where do you think cavitation is most likely to occur?”
“ It occurs on the side of the ship, where the horizontal surface contacts the ship," Zhou Zhi said.
"No, it should be generated at the propeller." Mai Xiaomiao thought for a moment: "The speed of the propeller is the highest point of transmission, and the outer edge of the propeller and the shaft have the same angular velocity, so the farther away from the center of the circle part, the speed is The higher it is, the churning water flow will undergo drastic speed changes throughout the propeller. This change will lead to drastic changes in local pressure, which can easily create conditions for cavitation."
"Well, Xiaomiao is still smart. Some." Qin Haifeng praised.
Zhou Zhi silently muttered in his heart, that's because you are both majoring in science, so it's so unfair to compare. If you have the skills, come and fight "Smoke Lock Pond Willow" and see who is smarter!
Qin Haifeng ignored what Zhou Zhi was thinking and continued to explain: "Gasification is actually produced by the boiling of water. We know that the boiling point of water at a standard atmospheric pressure is 100 degrees Celsius, and on Mount Everest on, due to the low air pressure , water can boil at a temperature as low as 69 degrees Celsius. "
"If there is a local low pressure below 2338.8pa in sea water at 20 degrees Celsius, the sea water will still boil and generate bubbles, which is called cavitation. of product The biological principle. "
"The place where low pressure is most likely to occur on the entire hull or submersible is naturally around the propeller."
"This is actually not difficult to understand, because of the pressure of the propeller. Moving at high speed, similar to the principle of an airfoil, the pressure on the back of the blade will inevitably decrease, thereby forming a suction surface. Low pressure will naturally occur. When the pressure is lower than the saturated vapor pressure of seawater, low-temperature boiling will occur. A large number of Bubbles are produced. ”
"For ships, such bubbles are very harmful. The difference between cavitation and high-temperature boiling is that when boiling water occurs, the bubbles generated inside will continue to grow, because the bubbles can continue to be obtained from the surroundings. Heat. "
"There is no heat input around the cavitation, only the strong squeezing of the surrounding high-pressure seawater. In a few millionths of a second, the cavitation generated by the propeller appears explosive. growth, later due to the high surrounding seawater Pressure, the cavitation is rapidly compressed until it collapses. When they collapse, they will form an explosive jet. The speed of this jet is often as high as thousands of kilometers per hour. Even a propeller made of high-strength alloy steel cannot withstand it. Its impact lasts for years. "
"In addition to jets, explosive shock waves are also produced when the cavitation collapses. This is just like the water on the back of the propeller cannot keep up with the movement of the propeller. Such shock waves tend to Causes the propeller to deform and break. "
"The third aspect is the huge noise produced when a large number of cavitation bubbles burst. For the military, such noise is often used to identify the type of opponent's ship, and even It is the sonar signature of a certain ship. For example, the noise of the Typhoon nuclear submarine designed by Ruby Design Bureau can be as high as 115 decibels. The legendary typhoon leaving the port in Vladivostok can be heard throughout the North Pacific. It is a joke about noise. , our navy , Of course, I hope that such a sound is as small as possible, and it is best not to have it at all."
"But as Xiaomiao said, as long as the propeller propulsion principle is used, such a pressure difference will inevitably occur. With drastic changes, it is impossible to avoid the formation of cavitation bubbles." Qin Haifeng took off his hat again and pointed at his white hair: "The white hair on your navy uncle's head is the product of fighting these bubbles. ”
Zhou Zhi vaguely knew that Qin Haifeng entered a scientific research unit of the Navy after graduating from university. Now it seems that it is probably a research institute that studies ship propulsion systems.
"So uncle, does he need our help for any projects?" Mai Xiaomiao asked: "Use Xiaozhi's computing power?"
"Absolutely." Qin Haifeng smiled and said: "Now All military units are having a hard time. Everywhere is converting the military into civilians and engaging in tertiary industries. We have also taken over the power system of a cruise ship. As part of the traditional design task, I designed several propeller solutions, hoping to verify which one is more effective in overcoming the cavitation effect and extending the propeller life. "This is a bit of a sprinkle of pepper on the grave - Damn it, the cruise ship is right. Why do the requirements for propellers need to be so high? You can just copy the world's articles, so why do you need to design them separately?
However, these may involve more secrets. Since Qin Haifeng said this, Zhou Zhi thinks it is better to understand it this way. After all, the girl sitting next to him is an out-and-out foreign nationality, navy The uncle came to see him, probably because he was in urgent need of computing power to solve the problem, and secondly, the situation had undergone some subtle changes since the disintegration of the great northern country.
The situation can be said to be a bit urgent.
"Even if we help the military and the tertiary industry, we are also supporting national defense construction!" Zhou Zhi smiled and said: "I know how difficult it has been for the army in recent years."
"Yes, elbow. You have a relationship with our army. Red Star Supermarket, a community chain of small supermarkets, helps retired soldiers solve their employment problems."
"You have helped with this matter. "You know?" Zhou Zhi's worries were put aside. Qin Haifeng had fully investigated himself and Mai Xiaomiao. Since he came to him after a full investigation, it meant that the issue of Mai Xiaomiao's nationality was in the boss's mind. In their eyes, the problem is not big: "As long as you need it, we will definitely support it."
"Our request is a bit unreasonable." Qin Haifeng said.
"Please tell us first, whether it's unreasonable or not, shouldn't that be our reaction?" Zhou Zhi said.
"That's right, we do want to borrow your computing power system." Qin Haifeng said: "But before borrowing, we need to understand the architecture and operating rules of your system in detail, and Your computing power forms the core.”
“This is actually not a big problem.” Zhou Zhi said: “But according to the consistent model of Clover Group, we attach great importance to IP protection. Currently, we have 90% of Xiaozhi’s core IP. Intellectual property registration has been completed and will not be used within twenty years Obtaining authorization from our group to build a system with the same architecture and using the same protocol is illegal and infringing."
"It's just like the typec interface you made, right?" Qin Haifeng said with a smile: "Listen. Let’s talk about how many billions we have made this year just by licensing the agreement. ?”
“It’s not that exaggerated.” Zhou Zhi was quite modest at the moment. In fact, the real situation is much more exaggerated than this, but it’s hard to elaborate: “The cost is still quite high, so it’s still there. Competing with the USB interface market ”
"You don't have to worry about IP issues. We are not an information system company." Qin Haifeng said: "What we need is computing power to verify our design plan."
"That's no problem. Isn't it unkind?" Zhou Zhi said with a smile.
"I haven't finished yet. We want to use Xiaozhi without your participation."
"What?!"