Chapter 396 Unify thoughts and concentrate strength

When Chang Haonan said this, he paused deliberately.

Obviously, not everyone can immediately accept this concept from a theoretical level.

But he had already thought of this.

"The report just made by Comrade Liu Yongquan talked about the design method of the compressor bending over Ye Shan, and I happen to have a calculation example here."

Chang Haonan released the next PPT, which showed an extremely complex high-aspect-ratio blade.

"You can join me and experience the design process of this 'ultra-high-load adsorption-type curved-sweep combined leading edge edge blade'."

This name directly made many people laugh.

As we all know, the longer the name, the stronger the person.

However, at the end of the 90s, the domestic trend had not been spoiled by Europe and the United States, and such names with a series of adjectives were not common.

Some keen people will find that Chang Haonan also marked several adjectives in front of the leaves in different colors, which seems to be intended to emphasize this point.

Sure enough, he then explained:

"Pay attention to the several factors that need to be considered at the same time during the design process of our blade, and will also affect each other."

"High load means that the single-stage boost ratio is high, and the efficiency of the blade itself must be sufficient; adsorption type means that a multi-slit adsorption type blade type is used to control the separation of the blade boundary layer; combined bending and sweeping means that bending and sweeping are applied at the same time. Sweep design, the blade is an asymmetrical complex shape in a three-dimensional space; the final leading edge strip means that we have also considered the adverse impact of the end wall effect on the compressor blade efficiency, and hope to reduce this as much as possible Influence."

The smile from before was gone.

When it comes to design, the more limiting factors there are, the more difficult it will obviously be.

And this "ultra-high-load adsorption-type curved and swept combined leading edge edge blade" is obviously the type with full buff.

Generally, when encountering this kind of situation, these design elements are optimized separately, and finally they are combined and put on the bench for actual machine testing, and the parameters are fine-tuned little by little.

This kind of gameplay that needs to be considered at the paper design stage is definitely a gameplay that I didn't dare to think about before.

But everyone’s smiles did not disappear, they just moved to Chang Haonan’s face:

"Although it is a little complicated, as a calculation example, it is certainly typical enough."

"Then let's go step by step. First, we will give the simplest curved Ye Shan shape..."

"..."

With the assistance of calculation examples, most researchers with engineering backgrounds finally gradually understood the new method proposed by Chang Haonan.

It was one-dimensional at first, then developed to two-dimensional, and then to quasi-three-dimensional...

Now this is called full three-dimensional, which sounds logical.

But after all, everyone here is a professional. After understanding it, they can almost immediately realize that the impact of this new theory on the field of aero-engine design is definitely not as ordinary as its name.

It is no exaggeration to say that if all the cakes Chang Haonan just drew can be realized, then the workload of the aero-engine compressor design process may be reduced by an order of magnitude!

Considering that most of the reductions in the middle are actual machine testing, the time, money and risks saved this time can almost cross the "quantitative change" and enter the category of "qualitative change".

In the past, the reason why aero-engine design was a job that required a lot of experience and a lot of practical testing was largely because the losses caused by viscous effects accounted for a large proportion of the total losses, including the amount of power added to the blades and clogging. It has a direct impact on surge margin, etc.

However, the quasi-three-dimensional design method that considers the S1/S2 flow surface highly relies on statistical methods (that is, guessing first and then iterating) for the calculation of viscous effects. Even the most cutting-edge method currently developed by General Electric and Rolls-Royce The streamline curvature method still requires a huge amount of experimental data to perform numerical fitting on aspects such as expansion loss, shock wave loss, gap loss, end wall loss, lagging angle and blockage estimation, which often takes several years. Even more than ten years...

Note that this is only the compressor part of the three major parts of the aircraft engine, and does not take into account the two hot-end components of the combustion chamber and turbine and the coordination of the three.

In general, with the current technical means, it is not unusual to spend 15-20 years designing a new engine from scratch without a core engine or old model as a basis.

In fact, it took about 10 years for the Turbofan 15 on the original timeline to move from instability to maturity.

And if the specific conditions of three-dimensional viscous flow can be given directly through numerical calculations, then even with a conservative estimate, the entire compressor design process can be completed in about 2-4 years.

Of course, the premise of all this is that the manufacturing level is up to standard and the things on the design drawings can be produced exactly as they are.

It's just that China's aerospace industry is full of shortcomings, which must be strengthened from the beginning, that is, the design stage.

The reason why the TORCH Multiphysics software designed by Chang Haonan emphasized the priority of ensuring the progress of the thermal coupling module from the very beginning is to expand its business in the field of material processing, especially the thermal processing of metal materials.

This happens to be an indispensable technology in the development process of high-performance aero-engine hot-end components.

China's lagging behind in the field of materials is often not due to the inability to produce the raw materials themselves, but rather to the fact that the products manufactured using the same raw materials do not meet the requirements.

Compared with the compressor as a cold-end component, the research focus of hot-end components, especially the turbine, is basically focused on "how to withstand the highest possible temperature."

Generally speaking, increasing the temperature in front of the turbine can directly increase the gas flow rate, and it will not directly affect fuel consumption. It is the simplest and crudest, but also the most intuitive and effective way to increase thrust - provided that the overall design level can meet the corresponding standards, otherwise it will only A very high turbine front temperature does not mean high performance. A typical negative teaching material in this regard is the later Japanese XF6-1. The turbine front temperature of 1600c is already on par with the fourth-generation turbofan engine, but the actual level is about the same. It’s almost like a smaller version of Taiwan’s RD33…

The minimum temperature in front of the turbine of the third-generation (foreign standard fourth-generation) turbofan engine cannot be lower than 1200c. If you want to achieve the target set by Chang Haonan for the turbofan 10, then this number will probably have to be increased. to above 1400c.

Obviously, no material can rely on its own properties to work stably for a long time at such a high temperature, so this requires some other tricks to help.

TORCH Multiphysics has the potential to solve this problem.

But this is no longer the focus of today.

Therefore, Chang Haonan only briefly talked about the research and development of hot-end components in the final outlook part.

No matter how awesome he is, it is impossible for him to introduce all the key technologies related to the third-generation turbofan engine in half an afternoon.

In fact, even this brand-new compressor design method only has time to throw out the concept and briefly explain it.

But enough is enough.

Looking at the eyes of the nearly two hundred people in the venue, Chang Haonan knew that his mobilization was quite successful.

Yes, although he has been talking about technology on the surface, he is not just talking about technology.

It’s more about confidence.

Although the design and production of the turbojet 14 has been finalized, and the orders have been so overwhelming that the 410 factory wants to allocate part to the 460 factory in Guizhou Province to relieve the pressure, at least before today, everyone has no idea whether they can produce a turbofan immediately. 10" I have no confidence in this matter.

For aviation power powers such as the United States and the Soviet Union (Russia), this kind of thing is basically not a problem.

Now that the previous generation model has been completed, it is basically logical to continue to develop the next generation.

However, in China, due to the fact that aerospace power projects have not been independently established for a long time in the past, there is often no technical inheritance relationship between various types of aeroengines, and each new model is almost started from scratch.

This is also the case between turbojet 14 and turbofan 10.

After being deeply improved by Chang Haonan, the former has certainly applied many new technologies, but after all, only a handful of people know this detail.

It is normal for most people to have concerns.

But when working on a project, especially one that requires concentrated efforts, the most taboo thing is that people are not aligned and are hesitant to look forward and backward.

Therefore, Chang Haonan’s report today is to give a clear answer – Turbofan 10 can definitely be produced!

Therefore, after finishing the technical content, he changed the subject:

"From the calculation example just now, you comrades should also be able to see that even if new design theories and design tools are applied, the research and development of the third-generation turbofan engine is still a huge task, and it is difficult to rely solely on one It takes two units to do it.”

"So, in this matter, I think it should be carried out through joint research and development by multiple institutions."

After Chang Haonan finished speaking, there was a burst of whispers in the venue.

Although he said "I think", anyone with a discerning eye can see that it is definitely not the opinion of one or two people who can express his position so clearly on such an occasion.

At the very least, it has to be approved by the Commission of Science, Technology and Industry for National Defense, or even higher-level permission has been obtained.

But the question is, how to unite?