Chang Haonan's luck is good.

Or it can also be said that Yao Mengna's luck is good.

Although because of the speed of convergence, she didn't actually get many complete results.

However, Chang Haonan still found an unexpected joy in it.

And with the naked eye.

In the numerical simulation of aero engines, due to the complexity of the structure of multi-stage axial compressors, it is very difficult to directly perform numerical calculations on multi-stage axial compressors, and there are many limitations in modeling and calculation.

Even if it is forcibly calculated, it will not be an overnight task to deal with the vast number of results.

Fortunately, after this period of training, Yao Mengna has become very proficient in model simplification.

Since the multi-stage axial compressor is composed of many "stages" with similar structures, the interaction between multiple stages can be ignored in the study, and a single stage can be calculated and analyzed, and the optimization of a single stage means that the compressor as a whole has been optimized.

The flow within a single stage is still relatively complex, and it is usually necessary to simplify it further, ignoring the work done by centrifugal force on the fluid, and thinking that the flow at different heights along the radial direction is the same, so that the three-dimensional flow in the "stage" can be simplified to a two-dimensional primitive-level flow.

For the vast majority of aviation engines, including the Turbojet 14, one base stage of the compressor consists of a moving blade grid and a static blade grid.

Therefore, this numerical simulation, which is only halfway through, is very clear.

Chang Haonan didn't take too long to discover the main points.

"Senior sister, you go and call the forest workers here, the priority of the leaf cracking problem needs to be improved, if we are efficient enough, we should still have time to use it on the vortex spray 14."

As he spoke, he pulled his notebook and pencil out of his pocket and began to record some key data against the screen, clearly preparing for a big job.

"Huh?"

Yao Mengna, who felt that she had delayed the progress and was a little weak-hearted, had been standing cautiously in the back just now, and raised her head unexpectedly after hearing Chang Haonan's request, and was stunned for about half a second before reacting.

"Oh...... Okay, I'll go right away! ”

After saying that, he turned around and ran out on the ground.

In her expectation, Chang Haonan should start to modify it immediately after reading the code, and if she is in a good mood, she will probably revise it while telling her ideas.

But in any case, she did not expect that the other party would find something useful directly from the incomplete calculations that she herself considered worthless.

She recalled that the first thing Chang Haonan did after entering the door just now was to stop calculating, and then immediately began to analyze the data.

"Senior brother, why does he trust me so much......

Yao Mengna's heart was filled with a hint of emotion, and the steps under her feet became more and more brisk, and her originally heavy mood was also a lot easier.

Even after pushing open the office door, the tone of his voice to Lin Shikuan involuntarily carried a slightly raised tail note:

"Lin Gong, Chang Bo will let you go over there!"

"Oh, okay, I'm going to gather the others."

Lin Shikuan hurriedly got up and went to find his other subordinates.

From Yao Mengna's uncontrollable smile, he naturally judged that there should be something good.

Maybe it's because the progress of compressor improvements has accelerated again?

The fact that the research was ahead of the timeline was something he had never even dreamed of.

But it's really something that has happened a lot in the last month or two.

So much so that although the wings and power of the 83 Project have been or are being reborn, the overall progress of the project has not lagged behind.

Thinking of this, Lin Shikuan's mood has also improved a lot, and the fatigue caused by working overtime for days in recent days has almost been swept away.

Although since Chang Haonan and Yao Mengna came to this computing center, his identity as the team leader has almost existed in name only, after all, he has thighs to hug, and the eyes of other people in the 83 Project to look at their digital design team have gradually changed from disdain to respect.

In this case, not only did he not feel "overheaded" at all, but he even wished that he could give up his position in exchange for the two great gods to cover him all the time.

In short, on this uneventful morning, the entire computing center seemed to be filled with a cheerful air.

So when Yao Mengna took Lin Shikuan and a few people back to the computer room, Chang Haonan turned around and saw several smiling faces side by side.

He tugged at his hair, somewhat puzzled.

"You ...... Have something happy today? ”

After all, in the recent period, as the deputy leader of the temporary research team who actually presided over the work, he himself felt that he was a bit too much in terms of pushing team members.

In particular, several people in the digital design team are under a lot of pressure because they don't see each other every day.

It's been a long time since I've had such a relaxed smile.

Of course, Chang Haonan didn't know how much drama Yao Mengna had added to herself in just a few minutes.

Because at the beginning, he did look at the data with the mentality of panning for gold in.

Originally, the purpose was just to see where the latter had been calculated, so that it could be further improved.

It's just that he really got it.

"The progress has accelerated again, of course it's worth rejoicing." Lin Shikuan replied without thinking: "We are ready for the next stage of work!" ”

Chang Haonan nodded, just thinking that Yao Mengna had just understood what he was doing, and told Lin Shikuan and the others, so he didn't ask any more questions, turned around and walked to the blackboard on the other side of the computer room to prepare to assign tasks.

A positive attitude is always a good thing.

"Now it's time for everyone to put aside the work at hand." Chang Haonan knocked on the blackboard and attracted everyone's attention:

"I need to calculate the Mach number distribution, static pressure distribution and limit streamline of several typical design points before and after the opening between the pressure surface and the suction surface of the blade under the two-dimensional primitive-level model, plus the entropy distribution of the trailing edge of the blade."

"The specific calculation method is no different from before, and because it is a simplified model, it should not be too difficult, but the workload will be more."

As soon as Chang Haonan said this, he heard the sound of gasping cold air behind him.

"Shhhh

The smiles of Lin Shikuan and the others froze on their faces:

"Both the movers and the Shizuko are counted?"

The functions of the moving vane grid and the static vane grid in the compressor are not the same, so the previous calculation of the wall limit flow spectrum of the blades of different bending designs brought nearly double the workload, which was very torturous.

"No, just Shizuko." Chang Haonan compared the structure diagram of the compressor hanging on the blackboard:

"I looked at my sister's previous calculations, and in the model of the same level of compressor, the effect of stator and mover seams is almost the same, so she helped us reduce the workload by half."

"I ......"

Yao Mengna had an expression of "how could I not know that I was so powerful".

But I felt the grateful eyes of everyone, and I knew that now was not the time to explain.

After calming down a little, she gradually realized that the difference between herself and this junior disciple was not only in the ability of numerical simulation.

What's more important is the mentality.

Because they are so eager to prove themselves, they only focus on the goal at the end point, and ignore other possible outcomes in the research process.

Thinking of this, Yao Mengna's expression also became serious.

She knew she wasn't like that before.

According to the plot analogy of martial arts, her state in recent times is a bit similar to going crazy.

If she can't find it and correct it in time, she may even go astray on the road of scientific research.

"Hoo ......"

Yao Mengna looked at the keyboard in front of her and breathed a sigh of relief:

"Good thing ......"

Just as Yao Mengna was introspecting, Chang Haonan, who had been smoothly arranging tasks just now, suddenly paused.

"Wait......"

He muttered to himself as he walked back to the monitor on his workstation and looked at the data on the screen again.

After a few minutes, he took out his pencil and notebook again, and began to calculate them under the blank gaze of everyone behind him.

Of course, it is impossible to calculate the complex numerical simulation process by hand, but the post-processing of the results of the numerical simulation is still within the scope of what the human brain can complete.

Many people have a feeling when they go to school that although a problem, especially a difficult problem, has been made, they can still deepen their understanding in the process of explaining it to others.

Even many details that you didn't pay attention to when you solved the problem yourself will be re-noticed.

Chang Haonan has just entered such a state.

In a flash of inspiration, he seemed to have thought of a better way to groov.

Ten minutes later, Chang Haonan stopped writing.

"Senior sister, according to the research of the research group of Bingcheng University of Technology, after the blade is cracked, does it only have obvious performance advantages when the angle of attack is relatively large?"

Although she didn't know what she was going to do, Yao Mengna nodded.

She almost memorized the content of that article: "At Ma = 0.4, the total pressure recovery coefficient of the slotted blade is only 7% better than that without slotting at the incoming flow angle of attack 0°, and if the Mach number is increased to Ma = 0.6, the total pressure recovery coefficient of the slotted blade at the incoming flow angle of attack is 0° and becomes about 1% smaller." ”

"That's right." Chang Haonan excitedly slapped the pencil in his hand on the table: "Comrades, I need to revise the task just assigned!" ”

After that, he went to the blackboard again.

"The basic principle of this jet fracture is that the mixing loss competes with the blowing effect, and when the mixing loss is larger, the total pressure recovery coefficient decreases, and vice versa, it increases."

Chang Haonan picked up the chalk as he spoke, slightly modified the blade schematic diagram on the blackboard, and changed the original straight jet seam into two corners.

"We can use this two arcs with different concave and convex directions to form an 'S' jet slit."

"The S-slit is a convergent and expanded channel, which can further accelerate the airflow, improve the jet effect, and the modified airflow inlet and outlet direction is closer to the mainstream direction, and can also reduce the blending loss."

The few people below looked at Chang Haonan in front of the blackboard in amazement, relying on the pen to modify the design on the spot.

They are used to all kinds of magical operations of this person, but there is still a sense of unreality in the face of this situation.

In the end, Yao Mengna was the first to understand what she meant:

"So this S-shaped jet slit can work very well even in level flight?"

"That's right."

Chang Haonan's own tone was also excited.

Such a flash of inspiration is certainly not uncommon with the help of the system.

However, this study on jet slits was not included in the system generation project.

And it wasn't something he had been involved in before he was born again.

In other words, it was completely dependent on the improvement of Chang Haonan's own ability.

……

After such an "epiphany", Chang Haonan became more comfortable with the improvement of the turbojet 14.

According to the original failure analysis, the surge-induced location was on the secondary rotor blades of the high-pressure compressor.

Therefore, the optimization of the bending and sweeping design is mainly aimed at the moving vane blades of a total of 7 high-pressure compressors, and the static vane blades whose main function is to carry out incoming flow compression are not overly complicated.

And it just so happens that the magical S-shaped jet slit can be set on the static blade grille.

This makes it possible to divide labor in parallel.

Development Progress*2

So after only half a month, an almost new turbojet 14 engine design scheme was finally presented to everyone.

Although due to problems with the progress of the project, the design of the combustion chamber and turbine did not change.

However, as one of the three major components of the core machine, and the most criticized high-pressure compressor part of the Turbojet 14 in the past, it has been completely turned upside down.

Submitted together with the design plan, there is also a schematic diagram of the compressor performance and flow field structure that Chang Haonan took the digital design team to spend more than a week.

and the most fundamental purpose of this large-scale design improvement - the general characteristic curve of the compressor.

Compared to before the improvement, the surge margin has increased by a full 25%.

Even in the event of harsh conditions similar to those of the previous prototype 01, the new turbojet 14 engines will be able to maintain normal operation on the common working line without surge.

What's more, after a lot of modifications, the design of the turbojet-14 compressor can no longer see the slightest shadow of the P11Ф-300 and "Spey".

It truly became our own engine.

Yan Zhongzhong stretched out his hand and trembled and touched the computer screen where the overall design of the compressor was drawn.

"This is 'Kunlun'."

"This should be our 'Kunlun'......"

Chang Haonan stood beside him, quietly looking at Yan Zhongzhong, who was almost in tears.

In the original timeline, due to the limitation of objective conditions, although the turbojet 14 engine was not launched with the 83 project, it was not until almost ten years later that a relatively stable design plan was come up.

At that time, the J-8 series had been discontinued, and the Huaxia Air Force no longer needed a turbojet engine with a thrust of 7.5 tons.

Although the QD series gas turbine based on the turbojet 14 core engine has achieved some success in the field of power generation, it can be regarded as giving this ill-fated aviation development project a plausible destination.

But after all, there are still regrets.

……

"There will be no more regrets like this."

"No more."

The business trip is over, and the next week will resume the update

(End of chapter)