Chapter 476 Turbofan 10, the 3.75th generation aviation engine!
The design review will officially begin soon.
Although the entire meeting will last two full days, everything is difficult at the beginning. The most important moment is actually the few hours in the morning of the first day.
Not only because the big leaders are there, but also because the most important design ideas and basic technical routes are usually concentrated in the first half of the day.
If there is no problem with this part, the entire project will be basically stable.
"This is a component-level analysis model of the turbofan 10 engine, which is also a zero-dimensional analysis model."
"In the overall design stage of the aircraft, a large number of design options need to be evaluated, taking into account the actual performance of our country's supercomputers is limited, this requires that the engine analysis model calculation speed is fast enough."
"At the same time, taking into account the accuracy requirements and the thermodynamic parameters of engine components required for engine noise and emission calculations, component-level performance models are used to calculate the thrust and thrust of the engine. Fuel consumption characteristics..."
"Therefore, we regard each component of the engine as a whole, only calculate the thermodynamic characteristics of the inlet and outlet of each component, and determine the common working relationship of the engine based on the common working relationship of each component of the engine. point, and finally obtain the thrust and fuel consumption of the engine and the status of each component..."
"In this step, we will not consider the casing and other auxiliary accessories for the time being, and simply calculate the design point and non-design point of the engine. Performance..."
“When calculating the design point performance, based on the input design point altitude and flight Mach number, as well as the engine bypass ratio, fan boost ratio, compressor boost ratio, turbine front temperature and other thermodynamic cycle parameters, the efficiency of each component or the total Pressure loss and engine air flow. ”
“According to the sequence of air flow through the engine components, the thermodynamic parameters of the inlet and outlet airflow of each engine component, the engine’s unit thrust and fuel consumption rate, etc. are calculated. Finally, according to the engine’s The air flow is used to calculate the net thrust of the engine and the dimensional parameters of the main sections of each engine component..."
These contents will be basic knowledge for aerospace designers twenty years later, and even graduate students in related majors. You can bring the content directly in two sentences.
But in the 1990s, except for Chang Haonan himself, there were few people in the country who seriously engaged in aviation engine design from scratch. Everyone was groping in the dark, so I still need to introduce it in detail.
On the other hand, these workflow-level things are also very important for the technical staff who sit further back and only attend the meeting.
Due to the different division of labor, most of the members involved in the research and development of the Turbofan 10 did not actually have the opportunity to truly touch the entire project. They only completed a certain small direction and even small details in accordance with the requirements of Chang Haonan or their immediate superiors. It’s just a task.
For the turbofan 10 itself, this division of labor is certainly reasonable.
But after all, Chang Haonan is planning to use these people as seed personnel in China's aviation power field.
Specific technical development is of course important, but for them, they still need to be exposed to the relevant ideas of overall design as early as possible.
The best opportunity is of course the two-day technical review meeting.
From Chang Haonan's perspective on the stage, many people can already be seen writing furiously with their heads down.
He even slowed down a bit specifically for this purpose.
After all, I have been a student. The teacher talked endlessly on the stage, and I wrote down the notes below. Who hasn’t experienced the feeling of taking off?
So Chang Haonan added two more sentences here:
“However, compared with other common zero-dimensional models, it benefits from the newly developed multi-physics coupling algorithm of our company. , in this step we can establish a mathematical model describing these aerodynamic processes relatively accurately, so there is no need to make too many simplifying assumptions. ”
"First of all, the airflow in the engine still needs to be treated according to one-dimensional flow, which is the core of establishing a zero-dimensional model."
"However, thanks to new technology, the turbine cooling bleed air, external The impact of air bleed and power extraction on engine performance, combustion chamber combustion and heat transfer models, and the impact of Reynolds number on the characteristics of each component are all taken into consideration..."
Now, it's not just the back who is taking notes. There are people sitting and eating melons.
Even Jiang Fuhe and others on the podium pressed the ballpoint pens one after another, making an almost uniform "click" sound.
“Next, I will introduce the aerodynamic and thermodynamic characteristics of each component in the order of atmospheric environment, inlet, compressor, combustion chamber, turbine, nozzle, manifold, and joint working model. …”
Just as Chang Haonan expected, after he released more detailed design data on the projection screen, whispers came from the entire judging panel.
After all, the structure of the Turbofan 10 is considered unique even in the field of turbofan engines in the world.
Even for a 9-stage compressor, 3+6 is generally chosen, and 2+7 is rarely used.
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-stage pressure ratio...
And the estimated thrust-to-weight ratio is 8.5-9.0 , which made everyone’s first reaction unbelievable.
Because this is already the technical indicator that third-generation major modification engines such as AL41F or F110-GE-132 have been pushed to the limit. These two models are actually still in the process of flight testing...
Good guys, the Turbojet 13 is still at the level of the 1960s, and the Turbojet 14 can already compete with the 80s. The F404 in the early 1990s went back and forth, and now it's the turbofan 10...
Directly catching up with the most advanced level in the 21st century?
Is it really just the same model for twenty years?
...
Until Chang Haonan's mouth was dry, he finally came to an end on the overall design and component-level analysis model, and entered the morning question session.
Even if the leaders sitting at the leadership table know a little bit about technology, they cannot be experts in the field of aviation development, so the first person to ask questions was Jiang Fuhe, who had already been impatient.
The question is naturally about the core machine structure that he has been itching about 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. It is of course very advanced, but I want to confirm the current compressor design level in our country. , can a total boost ratio of 25-26 be achieved through 2+7? ”
"In addition, it is also a 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 questions 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...really the fourth generation?"
"..."
The bottom almost exploded, but fortunately, it was next to it. There were senior leaders sitting there, so order was quickly restored.
Chang Haonan continued to explain:
"Regarding the issue of single-stage pressure ratio, we have made a huge breakthrough in the active control technology of blade separation flow. Compared with traditional compressor blades, the single-stage pressure ratio is significantly improved. With a total of 9 stages of compressor, it can be achieved The total boost ratio required in the design specifications."
"As for the specific technical details, according to the plan, they should be discussed this afternoon."
After finishing speaking, Chang Haonan spoke again. A heavy statement was added at the end:
"In fact, if it were not for the fact that the inlet structure of the engine installed on it has a very good boost capability, this 2-7-1-1 The structure can even bring the pressure ratio to about 28, but in that case, the supersonic performance of the J-10 and J-11 will definitely not be optimistic."
"That's why you specifically reduced it. Level 1 fan?”
Liu Zhenxiang seemed to understand something.
“Yes, but not entirely.”
Chang Haonan said and turned the PPT back to the page where the overall structure of the turbofan 10 was drawn:
“Generally We believe that third-generation engines, such as AL41F and F110GE132, which use some enhanced fourth-generation engine technologies, are called 3.5 generations"
"And our turbofan 10 is essentially a It is a fourth-generation engine, but because our country still has huge shortcomings in materials and processes, it is unable to meet some of the requirements of a true fourth-generation engine, so we have to lower some performance requirements.”
"If I have to say it, I probably have to use some fourth-generation engines that have been weakened by the third-generation engine technology. Therefore, we are used to calling it... the 3.75th-generation engine."
This statement is enough The words are concise and concise, let alone experts, even leaders can completely understand it.
Does it mean you are ready to enter the international leading level?
Looking at the speechless audience, Chang Haonan left behind the podium and walked to the middle of the podium:
“That’s why I designed a push-to-weight ratio of 10 to 1. The seven-stage high-pressure turbine required for the first-stage engine cannot be changed after all, and the fan can be added later.”
"In the future, we only need to make in-depth improvements based on this core aircraft to develop a truly fourth-generation aviation engine!"
(End of this chapter)
< br>