The design review will begin shortly.

Although the whole meeting lasted two full days, everything was difficult at the beginning, and the most important thing was actually the first few hours in the morning.

Not only because the big leaders are there, but also because the most important design ideas and basic technical routes are generally concentrated in the first half of the day.

This part is no problem, and the whole project is basically stable.

"This is a component-level analysis model of the turbofan 10 engine, which is a zero-dimensional analysis model."

"In the overall design stage of the aircraft, a large number of design options need to be evaluated, and considering the limited actual performance of China's supercomputer, this requires the engine analysis model to be calculated fast enough."

"Taking into account the accuracy requirements and the thermodynamic parameters of the engine components required for engine noise and emissions calculations, the component-level performance model was used to calculate the engine's thrust and fuel consumption characteristics......"

"Therefore, we regard the various parts of the engine as a whole, only calculate the thermodynamic characteristics of the inlet and outlet of each component, determine the common working point of the engine according to the working relationship of each component of the engine, and finally obtain the thrust and fuel consumption of the engine and the state of each component......"

"In this step, we will ignore the casing and other auxiliary parts for the time being, and simply calculate the design and non-design performance ...... of the engine."

"When calculating the design point performance, the input design point altitude and flight Mach number, as well as the thermodynamic cycle parameters such as the engine bypass ratio, the fan boost ratio, the compressor boost ratio, the pre-turbine temperature, the efficiency or total pressure loss of each component, and the engine air flow."

"According to the order of the air flow through the various parts of the engine, calculate the thermodynamic parameters of the inlet and outlet airflow of each part of the engine, the unit thrust and fuel consumption rate of the engine, etc., and finally calculate the net thrust of the engine and the size parameters of the main cross-section of each part of the engine according to the air flow of the engine......"

These contents belong to the basic knowledge of aviation designers and even graduate students in related majors after 20 years, and they can be directly brought to the past in two sentences.

But in the 90s, except for Chang Haonan himself, there were few people in the country who had been seriously engaged in aviation design from scratch, and everyone was groping in the dark, so it was necessary to introduce it in detail.

On the other hand, these workflow-level things are also quite important for technicians who sit further back and just sit in the meeting.

Due to the different division of labor, the vast majority of the members involved in the research and development of turbofan 10 actually did not have the opportunity to really touch the whole picture of the entire project, but only completed a small direction or even a small detail task according to the requirements of Chang Haonan or his immediate boss.

For the turbofan 10 itself, this division of labor is certainly justified.

But Chang Haonan is ready to use these people as seed personnel in the field of Huaxia Aviation Power.

Of course, the specific technical development is important, but for them, it is important to be exposed to the ideas related to the overall design as early as possible.

And the best opportunity, of course, is the two-day technical review meeting.

From Chang Haonan's perspective on the stage, I can already see that many people are bowing their heads and writing hard.

He even slowed down a bit specifically for this.

After all, he is also a former student, and the teacher is talking endlessly on stage, and he writes in the notes below that who has not experienced the feeling of taking off.

Therefore, Chang Haonan added two more sentences here:

"However, thanks to our newly developed multiphysics coupling algorithm, we can build a mathematical model describing these aerothermodynamic processes with relative precision in this step, compared to other common zero-dimensional models, so there is no need to simplify assumptions too much."

"First of all, the airflow in the engine should still be treated according to the one-dimensional flow, which is the core of establishing the zero-dimensional model."

"However, thanks to new technologies, the effects of turbine cooling, external bleed air and power extraction on engine performance, combustion chamber combustion and heat transfer models, and the influence of Reynolds numbers on the characteristics of individual components can all be taken into account......

Now, it's not just the melon-eating crowd sitting behind me who are taking notes.

Even Jiang Fu and others on the rostrum pressed the ballpoint pen one after another, making an almost uniform "click" sound.

"Next, I will introduce the aerothermodynamic characteristics of each component in the order of the atmospheric environment, the air intake, the compressor, the combustion chamber, the turbine, the nozzle, the manifold, and the co-working model......

As Chang Haonan expected, when he released more detailed design data on the projection screen, the entire jury immediately heard the sound of ear-to-ear talking.

After all, the structure of turbofan 10 is unique even in the field of turbofan engines in the world.

Even if it is a 9-level compressor, 3+6 is generally chosen, and 2+7 rarely occurs.

What's more, the pressure ratio of his high-pressure compressor is very high, and the subtracted first-stage fan even seems to be deliberately lowering the first-level pressure ratio......

And the expected thrust-to-weight ratio of 8.5-9.0 makes everyone's first reaction unbelievable.

Because this is already a technical indicator for the AL41F or F110-GE-132 and other third-generation overhaul engines to be squeezed to the limit.

And both models are actually still in the process of flight testing......

Good guys, the turbojet 13 is still at the level of the 60s, and the turbojet 14 can already go back and forth with the F404 in the early 80s, which is the turbofan 10......

Catching up with the most advanced level of the 21st century?

Is it really just a model for 20 years?

……

It wasn't until Chang Haonan's mouth was dry that he finally finished the overall design and component-level analysis model and entered the morning question session.

Even if the leaders sitting in the leadership seat know a little technology, they can't be experts in the field of aviation development, so the first person to ask questions is Jiang Fuhe, who has been impatient for a long time.

The question, of course, is about the core structure of the machine that he has been itching for a long time.

"Comrade Chang Haonan, I noticed that you used a structure like a 7-stage high-pressure compressor on the turbofan 10, of course, it is very advanced, but I want to confirm that the current level of compressor design in our country can ensure that the total boost ratio of 25-26 can be achieved in the form of 2+7?"

"Also, for the same 9-stage compressor, why choose 2+7 instead of the more common 3+6 form?"

And Chang Haonan's answer was even more direct:

"These two issues are actually the same thing."

"Because the core engine of the turbofan 10 is actually the core engine of a fourth-generation engine."

"Huh?"

“woc……”

"Really...... Is it really the fourth generation? ”

“……”

The bottom was almost directly fried, but fortunately, there was a big leader sitting next to him, so order was quickly restored.

Chang Haonan went on to explain:

"Regarding the problem of single-stage pressure ratio, we have made a huge breakthrough in the active control technology of blade separation flow, the single-stage pressure ratio is significantly improved compared with traditional compressor blades, and the total pressure boost ratio required in the design index can be fully achieved through a total of 9 stage compressors."

"As for the specific technical details, according to the plan, they should be discussed this afternoon."

After finishing speaking, Chang Haonan added a blockbuster speech at the end:

"In fact, if it is not for the fact that the inlet structure of the engine installation object itself has a good boost capacity, this 2-7-1-1 structure can even achieve a pressure ratio of about 28, but in that case, the supersonic performance of J-10 and J-11 is definitely not very optimistic."

"That's why you specifically reduced the level one fan?"

Liu Zhenxiang seemed to understand something.

"Yes, but not exactly."

Chang Haonan said and turned the PPT back to the page where the overall structure of the turbofan 10 was drawn:

"Generally speaking, we think that the AL41F and F110GE132 are called 3.5 generation engines that use some fourth-generation engine technology enhancements."

"And our turbofan 10, it is essentially a fourth-generation engine, but because China does still have huge shortcomings in materials and processes, there is no way to achieve some of the requirements of the fourth-generation engine in the real sense, so we have to reduce some performance requirements."

"If I have to say, I was probably forced to use some fourth-generation engines that had been weakened by third-generation engine technology, so we are used to calling it ...... 3.75th generation engine. ”

This statement is concise enough to say that even the leaders fully understand it, not to mention the experts.

Does it mean that you are ready to enter the international leading level?

Looking at the audience who were speechless, Chang Haonan left behind the lectern and paced to the middle of the podium:

"That's why I designed the 7-stage high-pressure turbine required by the thrust-to-weight ratio of the 10-stage engine, after all, the structure of the core engine is not easy to change, and the fan can be added later."

"In the future, we only need to make in-depth improvements on the basis of this core aircraft, and we can develop a real fourth-generation aviation engine!"

(End of chapter)