The military-industrial scientific research system of the academic master.

Chapter 87 Problems with Aviation Power

On the other side, Hao Jing and Yan Liang.

After completing the analysis of the engine surge failure, Chang Haonan finally made time to rest for a few hours.

There are still some comrades in the power joint research team who are inspecting and analyzing the damage to the No. 01 prototype to confirm the specific impact of the failure and eliminate other possible causes of the accident. It is estimated that they will have to wait until tomorrow morning.

Of course Chang Haonan does not need to complete this job.

But his mission is far from over.

After all, identifying the problem is only the first step in a long journey of thousands of miles.

The key is still to solve the problem.

Although the compressor of the turbojet engine and the air-conditioning fan he studied before can be classified as "turbine machinery", the difference between them is similar to that of the Pilot 225 and An-[-], which also belong to the "aircraft" category.

After dinner, Chang Haonan took a walk around Yan Liang's factory while thinking about the next plan.

Since he has a work permit from the August [-]rd Project on his chest, he can naturally move freely throughout the entire site. Only a few buildings or rooms require additional permissions, and normal walking is obviously impossible and there is no need to go to such places. .

So along the way, Chang Haonan's mind was completely focused on aviation engines.

The traditional idea of ​​"steady wall flow pattern" has been used in the current impeller machinery design system.

Once the flow separation caused by the airflow expansion flow in the compressor occurs, it is no longer within the range that the above flow pattern can describe.

Since conditions other than wall flow were not considered from the beginning, it is almost inevitable that flow disorder or loss of control will occur under non-design conditions.

From this perspective, the most direct and effective way is to increase the stall margin and delay the occurrence of flow separation by changing the blade design.

In particular, the turbojet 14 is an existing design. If modifications are to be made, the original design ideas must be retained.

After a period of research on swept blades, Chang Haonan is confident that he can solve this problem quickly. As long as the efficiency of the 410 factory responsible for engine manufacturing can keep up, it will not have a particularly significant impact on the progress of the [-]rd Project.

But for the Chinese Air Force, which is about to enter the third-generation aircraft era, the Turbojet 14 can only be a transition.

It cannot hold up the future sky of a great country.

Chang Haonan's thoughts flew to further places involuntarily.

J-10 and J-11, both third-generation aircraft have the same target power.

Turbofan 10.

But he borrowed a joke that was popular on the Internet before he was reborn.

Is the 1996 Turbofan 10 coming?
——Tathagata.

It is truly the Tathagata.

At this time, nearly 10 years have passed since the establishment of the Turbofan 10 project, but what about the progress of the project itself...

Basically there is no progress.

Or Schrödinger's progress.

The turbofan 1987 project initiated in 10 and the turbojet 14 developed almost simultaneously.

It can be said that without any engine design experience, even second-generation engines such as the turbojet 14 have obvious traces of patchwork and reference, let alone the situation of the turbofan 10.

Although the design goals have not been changed and the design location has been changed as many times as the Turbofan 6, it is inevitable to overturn the overall design plan many times.

Even the original plan was changed midway.

At this time, the turbofan 10 should be in the process of a certain design reset.

Actually this is normal.

The steady wall flow pattern mentioned earlier has its limits after all. On this theoretical basis, it is almost impossible to design a compressor with high pressure ratio and high load.

Because there are two sides to the matter of flow separation.Chang Haonan once again thought of the field of aircraft design that he was more familiar with and experienced.

About 20 years ago, the design idea of ​​the aerodynamic distribution of the aircraft shape crossed from "steady attached flow pattern" to "steady/detached vortex mixed flow pattern".

That is, from "suppressing flow separation" to "utilizing flow separation"——

Intentionally creating a high-angle-of-attack decoupling flow pattern for the aircraft, and using the concentrated vortices generated by flow separation to obtain additional vortex lift. This not only greatly increases the lift of the wing, but also greatly expands the range of the wing's angle-of-attack, making the aircraft's performance unprecedented. A leap.

This is reflected in the products at the stage when fighter jets evolve from second-generation aircraft to third-generation aircraft.

"Can this kind of thinking be introduced into the aerodynamic design of the compressor?"

This idea jumped into Chang Haonan's mind almost without warning.

Of course, this is difficult.

Because it is necessary to fully understand the internal flow of the cascade, especially the rules of separation flow.

A common path taken by scientific research is from complexity to simplicity, and then from simplicity to complexity.

First, abstract the specific natural phenomenon into a simpler model, and obtain a basic understanding after conducting research. Then gradually cancel the assumptions made, modify and expand on the basis of the basic understanding, until finally the answer to the complex specific phenomenon is obtained. A comprehensive understanding of.

Typical examples are from Newton's classical mechanics and Maxwell's classical electromagnetism, to relativity and quantum mechanics.

In terms of boundary layer flow, we have just completed the "from complex to simple" stage.

In terms of numerical simulation, it can probably only achieve two-dimensional steady calculations, which are even some distance away from quasi-three-dimensional calculations.

Thinking of this vast knowledge, Chang Haonan's brain felt a little swollen.

Before he was reborn, he was not a powerful person. He only knew a lot of things but didn't know why.

And the above mentioned are only problems in the field of aero-engine compressor design.

In addition, there are combustion chambers, turbines, fans, bearings, tail nozzles...

After the design is completed, it must be implemented into manufacturing.

……

There is no doubt that the system's capabilities are powerful, but there are also two limitations. One is the points requirement, and the other is that one needs to have a certain theoretical foundation first and complete the basic idea framework before the project can be formed.

Although at the beginning of his rebirth, Chang Haonan had already realized that his own strength alone was completely insufficient.

But after all, he underestimated how quickly the pressure would come.

"call--"

Chang Haonan let out a long breath.

"There still has to be a team, and it has to be a team with me as the main player."

In addition to the "output" process of promoting the new models and new theories he has developed, he also needs an "input" process.

That is to let others be responsible for constructing the basic thinking framework, or at least provide him with sufficient theoretical knowledge.

Opening the system panel and looking at the person with only level 1 engineering experience, Chang Haonan shook his head mockingly.

Before rebirth, I had only led small projects with no more than 4 people including myself.

After being reborn, I have only taken along a few people like Lin Shikuan so far.

There is progress, but not enough.

Thinking of this, he stopped and prepared to walk back.

The current work of improving the turbojet 14 seems to be a good opportunity.

(End of this chapter)