Great Power Ship

Chapter 130 Supercavitation (for subscription)
In fact, not only the chief of the navy was so amazed, but also the other leaders present.

Because the thing in Wen Dawei's hand is not so much a bullet, but a crossbow bolt from the cold weapon era, because except for the shell or the shell of the bullet, the entire bullet is almost as long as an adult's palm, and the shape is not unique, it is completely weird .

However, Cai Xiaohui nodded very positively: "It's the pistol bullet of an underwater pistol, but this is just a scale model. It uses the shell casing of the 64-type pistol bullet, and we use the long warhead made of high-strength alloy steel. .”

"Can this thing be fired underwater? You know that ordinary bullets can't even shoot out one meter in the water, but this bullet can be made longer?" The chief of the navy couldn't help being a little curious. It was the first time he had seen such a weird bullet. Yes, so I asked in more detail.

"I didn't know much about this before. It was only after I came to Zhujiang Factory and communicated with Assistant Wen that I became clear about the inside. Oh, by the way, Assistant Wen's postgraduate research direction is underwater fluid mechanics and acoustics. He knows this better than me!"

Cai Xiaohui also said whatever he wanted, without any reservations, he took the matter of Wen Dawei's graduate student into account, and gave up his chance to perform in vain.

It’s right to say that you don’t turn your head, and it’s right to say that you don’t forget the person who dug the well when you drink water. It depends on the angle you stand at, but Cai Xiaohui doesn’t care about these things.

Those precious brain cells of his still have to be put into the gun business he loves, so they can't be wasted to useless places.

Others don't know Cai Xiaohui's straightforward and free-spirited character, but Wen Dawei can understand, in his previous life, he had such a number one person in his team, Wen Dawei is very easy to use, but he often loses the chain on certain critical occasions.

The current situation is similar, how rare is the opportunity to perform in front of the chief of the navy, if Cai Xiaohui says no, then don’t, what can you do with him?
Wen Dawei was also helpless, and could only take up the conversation with a smile: "It's such a chief, this warhead is not an ordinary warhead, but a special warhead that uses the theory of supercavitation to be launched underwater..."

While talking, a few scientific researchers with great eyesight brought over a blackboard, with a line of large characters written in chalk in the center of it:
"7.62mm Underwater Pistol"

Below is a hand-painted conceptual drawing of an underwater pistol with tape. Wen Dawei pointed to the schematic diagram of the underwater launch of the pistol and continued: "When an object moves underwater, the water flowing through each point on the surface of the object The speed is usually not the same, if the influence of gravity is not considered, according to Bernoulli's principle..."

Wen Dawei wrote on the blank space of the blackboard with chalk: p+1/2ρv2+ρgh=C
The classic Bernoulli equations then go on to say: "By this equation, it can be seen that an increase in flow rate will cause a local pressure drop, and when the pressure on the surface of the moving body drops to close to the saturated vapor pressure of water at that temperature, the local water will Be vaporized and form a steam cannon.

Such initial cavitation can occur at pressures above or below the vapor pressure of water. At higher flow rates, there are many points at the interface between the object and the liquid where the pressure drops to the vapor pressure of the liquid and several small bubbles appear. In the case of dispersed steam cannons, when the pressure increases, these small bubbles will collapse rapidly. This process is called cavitation. "

While talking, Wen Dawei wrote several more complex mathematical formulas on the blackboard, and then further explained: "In the early stage of cavitation imagination, the life of each small bubble is extremely short, but when the flow rate increases, the object There is a pressure low enough to cause cavitation on a larger area, and the cavitation will exist on a larger area of ​​the object at this time. At a high enough flow rate, these cavitation bubbles will no longer collapse, and form an almost Large bubbles filled with water vapor.

If the cavities on the object have completely covered the object, these cavities are called fully developed cavities, the so-called 'supercavitation'! "

Speaking of this, Wen Dawei pointed to the underwater pistol on the concept map: "According to this principle, we take the function of the speed of the underwater vehicle, the internal pressure of the cavitation, and the external pressure of the cavitation as the function of the cavitation number. When the cavitation number is 0.01, the speed is 100. m\s, the assistant can be reduced to 5% of the fully wet state.

When the cavitation number is 0.0001, the assistant can be reduced to 0.1%. It can be seen that by providing air bubbles around the underwater vehicle, reducing the area of ​​the underwater vehicle in contact with water can greatly reduce the resistance of the underwater vehicle. "

As soon as the words fell, Wen Dawei clicked heavily on the concept map: "And our underwater pistol is built according to this principle!"

Hearing Wen Dawei's introduction, the head of the navy slightly nodded, and then frowned again: "What you said just now is very similar to a very hot supercavitating torpedo copied from abroad!"

"The chief is really astute. The source of our idea for this underwater pistol is the supercavitation torpedo!" Wen Dawei hurriedly sent a fluffy flattery: "After all, our superior unit, Lidong Factory, is one of the largest factories in our country. There are not many torpedo factories, and our management unit, the Southwest Ordnance Industry Bureau, is also a full-time department that manages the production of military products, so our Zhujiang factory has a tradition in this area, and it has accumulated technology!"

"Comrade Dawei is right. Our Southwest Ordnance Industry Bureau has always put military products first, and quality first..." As soon as Wen Dawei's voice fell, Deputy Director Wang took over the conversation with a smile on his face: "For military products The research and exploration of the Southwest Ordnance Industry Bureau has always been the focus of our Southwest Ordnance Industry Bureau. For example, the supercavitation torpedo mentioned by Comrade Dawei, we have done related research in the mid-70s. Some technologies have inherited the research results of that year..."

Deputy Director Wang was already good at eloquence, but once the chat box was opened, it would be eloquent, and he was short of exaggerating the Southwest Ordnance Industry Bureau's military production.

There is no way, the transformation and reform of civilian products by the Southwest Ordnance Industry Bureau is bound to arouse the resentment of old customers and troops for many years.

This is nothing more than an ordinary civilian production unit. The key problem is that the Southwest Ordnance Industry Bureau was born as a specialized military production unit, and the brand of national defense and military industry can never be lost.

The first is the issue of identity. If this brand is gone, why is the Southwest Ordnance Industry Bureau still in the ordnance industry system?You can directly stand on your own and be responsible for your own profits and losses.

The problem is that if we really want to do this, the huge Southwest Ordnance Industry Bureau can't grasp it at all.

This leads to the second key point, which is also the most important factor, and that is the policy issue. Military product orders have high quality requirements and the purchase price has not changed for many years, resulting in many manufacturers having no profit at all.

But if there is no profit, as long as you have the status of national defense and military industry, the state will help you.

After all, not all of the many factories under the Southwest Ordnance Bureau are as capable as the Zhujiang factory, and many are struggling below the loss line, so keeping the status of national defense and military industry is tantamount to keeping the survival of these factories.

Because of this, let alone the head of the navy boasting himself as a flower, as long as the head of the navy is happy and asks Deputy Director Wang to dance on the spot, Deputy Director Wang will not frown...

(End of this chapter)