my scientific age

Chapter 249 Turn stress into appetite!

Regarding the issue of nozzle materials, it mainly focuses on the material supply link.

China is a country with a serious shortage of copper. More than 95% of domestic copper imports are supplied to major arsenals. There are very few copper coins and copper products on the market, and the purity of these imported copper metals is about 99%, which cannot reach industrial grade purity. copper standard.

Industrial grade pure copper, commonly known as red copper, has a content standard of more than 99.95%, so that it has the best thermal conductivity. This high-end copper raw material belongs to one of the national strategic resources. China has no production capacity and relies on foreign imports.

"It is unrealistic to buy copper with a purity of more than 99.95%, and it is not allowed economically. It seems that you must be self-reliant and establish a complete copper production system in the base area, mining and smelting, and finally electrolytic refining. In this way, you can get red copper, not only oxygen Gun nozzles need to be used, generators, transformers, telephone lines, bullets and shells, etc., all need copper." Yu Hua thought silently, and wrote down the solution for the supply of nozzle materials in a notebook.

Electrolysis, which is the most suitable copper production process in the base area, uses blister copper as the anode, pure copper as the cathode, and copper sulfate solution as the electrolyte. After electrolysis, the purity can reach 99.99%.

It is easier to solve the problem of material supply, and now we go back and start the most difficult part.

How to design the nozzle structure to meet the requirements?
"In order to obtain supersonic airflow, increasing the pressure and speed is the key. The Laval nozzle structure of the rocket engine should be used here. Although the straight-tube structure design similar to the turbofan engine can also obtain supersonic airflow, the technical requirements are very high."

Yu Hua turned the pencil in his right hand, and his memory emerged. His brain analyzed the video data of the oxygen blowing furnace technology at Station B that he had browsed and learned, and synthesized the important knowledge he had learned in the Department of Mechanical Engineering to quickly determine the nozzle structure design.

Laval nozzle structure, the main structural design of the rocket engine nozzle in the future, the nozzle is divided into two parts. Expansion, also like a funnel.

From a fluid mechanics standpoint, the Laval nozzle is an interesting design.

Generally speaking, the movement of high-pressure pure oxygen in the nozzle follows the principle of 'when the fluid moves in the tube, the flow velocity is large at the small section, and the flow velocity is small at the large section'. In the first half of the nozzle, the high-pressure pure oxygen continues to accelerate as the nozzle converges , reaching the critical point of airflow velocity in the narrow throat area.

At this time, the subsonic airflow cannot continue to increase, and it no longer follows the principle of 'the smaller the cross-section is, the larger the flow rate is, and the larger the cross-section is. Part of the Laval nozzle will expand rapidly, increasing the cross-sectional area of ​​the airflow.

This ingenious design makes the speed and pressure of the airflow suddenly increase sharply, increasing by an order of magnitude from 300 meters per second to 2-3 kilometers per second, which is about Mach 7-8.

The oxygen lance nozzle adopts the Laval nozzle design, which can easily obtain supersonic airflow, and the rocket engine adopts the Laval nozzle design to obtain an unprecedented huge thrust.

In addition, the well-known ballistic missiles, anti-aircraft missiles, air-to-air missiles and other engine nozzles basically use the Laval nozzle structure.

Easy to use, really.

However, since rockets and missiles were not born in this era, people have not really recognized the value of the Laval nozzle. Since it was patented by the Swedish Laval invention, it has been put at home to eat ashes.

Yu Hua has already conceived the shape and structure of the entire Laval nozzle in his mind. Holding the pen in his right hand, he drew the oxygen lance nozzle based on the Laval nozzle on the new design drawings.

The entire oxygen lance nozzle adopts a porous structure, with a total of three micro-Laval nozzle structures. Subsequently, the mathematical model of the real-time dynamic nozzle established by Yu Hua was analyzed. After a few minutes, the analysis results were obtained.

Under the condition that the pressure and flow of high-pressure pure oxygen flow are constant, the supersonic flow of the three-hole design is divided into two streams, and the speed is just moderate, which will not damage the bottom lining of the 2T-class converter.

With the single-hole structure nozzle, under the same working oxygen pressure parameters, the airflow speed can reach 2 kilometers per second, which will cause serious impact on the lining of the furnace bottom.

"Just use the three-hole nozzle, which is very suitable for the 2T-level experimental converter." After obtaining the analysis results, Yu Hua immediately decided to use the three-hole nozzle, and then began the next design - the gun body.

Since the oxygen lance needs to work in a converter with extremely high temperature and heat radiation, in order to avoid the oxygen lance being damaged by heat, in addition to an oxygen supply pipe, a cooling and heat dissipation pipe should also be added.

Air cooling will definitely not work, and liquid cooling must be used.

For the design of the gun body, Yu Hua uses a three-pronged solution. The central pipe is the main oxygen supply pipe, the second pipe is the cooling water inlet, the third outermost pipe is the cooling water outlet, the gun body and the gun tail. Flanges and sealing rings are used at the connection.

On the design drawings, a three-hole nozzle oxygen lance composed of standard lines and symbols is gradually formed. Yu Hua builds a mathematical model while designing, conducts calculation simulations, obtains data, and then makes modifications based on these calculation data.

This is Yu Hua's unique scientific research advantage.

Time passed by minute by minute. When all the students in Tsinghua Academy finished their morning exam subjects, Yu Hua retired from the energy-intensive research and development state, put down his pencil, rubbed his slightly swollen temples, and ended today's oxygen lance research and development. Work.

At present, about 50% of the oxygen lance design work has been completed, and the current efficiency is expected to be completed in three days.

"Calculation simulation is good, but it consumes too much. More than eight hours of efficient study time a day, using the thinking computer can only maintain 50 minutes of full-load use time. If there is any magic medicine that can make me run 24 hours a day, and not Just hurt my body." The golden mathematical symbols in the thinking center continuously released the meaning of coldness, and the swelling and discomfort in Yu Hua's brain gradually receded, and he felt his own state with his heart, and sighed softly.

Unfortunately, this 'magic medicine' does not exist.

"Tomorrow is July [-]st. There are still seven days left until the Lugouqiao Incident. I don't know where the German machine tools have gone. I hope they can arrive at Tianjin Wei before the fall of Peiping and Tianjin. The time is getting more and more urgent."

Yu Hua didn't put his mind on looking for some magical medicine, and thought silently about the upcoming Lugou Bridge Incident: "Also, I don't know if the prototype unit of Yu's Seven Pagodas has arrived at the base."

On July [-], the Lugou Bridge Incident broke out.

On July 29, Peiping fell.

On July [-], Tianjin fell.

The window period left for Yu Hua in the northern region is only the last 30 days. If the German machine tool equipment traded is still not delivered before the fall of the two cities of Pingjin and Tianjin, then the entire technology-for-equipment plan may be directly aborted.

This batch of German machine tools determines the machinery manufacturing industry in the base area, and the Yu's Seven Towers prototype unit determines the sulfuric acid industry and the explosives industry in the base area.

As the Lugou Bridge Incident got closer and closer, a sense of oppression from a major historical event followed and enveloped Yu Hua's heart.

Yu Hua took a deep breath, suppressed the emotions in his heart, kept his head calm and calm, packed up the oxygen gun drawings on the table, got up and went to the cafeteria to cook.

When under pressure, Yu Hua, who is a cook, likes to relieve stress by eating.

Turn stress into appetite.

The cafeteria was overcrowded, and the students taking the final exam were talking a lot about how difficult the subject exam questions were this morning. Yu Hua came out of the crowd with a full meal and found a place to sit down.

Today's lunch was very rich, with steamed bread with white flour, mustard, porridge, and a hard-to-find oily dish—potato stew. The school specially added a dish to reward the students who took the final exam.

There were two whole pieces of fat meat the size of thumb caps on the dinner plate, trembling gently, exuding a mind-blowing temptation.

To be fair, it's really not unreasonable that Yu Hua has only eaten lean meat before and now only eats fatty meat.

Living conditions are really hard.

The key is that this is still the standard of food at National Tsing Hua University, and many places can't even eat rice.

When Yu Hua sat down and prepared to cook, suddenly, a faint scent came, and there was only a young girl sitting in front of him.

"Hello, are you Yu Hua's classmate?" the young girl asked Yu Hua.

Yu Hua, who was disturbed, frowned slightly, raised his head to look at the girl, and suddenly felt familiar: "I am, what's the matter with you?"

Isn't this the girl who asked him for directions to the editorial office of the journal last time?
"Hello, my name is Ye Qingyue, and I am the first review editor of the editorial department of Tsinghua Journal." Ye Qingyue explained with a gentle smile.

(End of this chapter)