After participating in the first off-line ceremony of the domestic J-11, as the chief designer of the turbofan 10 project, Chang Haonan must go to the 606 Institute and the 410 factory since he arrived in Shengjing.

After all, it's all coming.

For Huaxia's aviation industry, the turbofan 10 is almost a "zero-based" engine, and some of the technologies developed in the process of developing the turbojet 14 can be used, but not much.

As for the older models, then there is no reference value at all.

Before the turbojet 14, Huaxia did not even have an aero engine research and development system in the strict sense.

Therefore, in order to improve efficiency, Chang Haonan has adopted the operation of design and production lines completely in parallel for the first time in this project, at the cost of increased risk and workload.

"Mr. Chang."

Chang Haonan's visit to Shengjing was originally a temporary intention, and he only showed up in Factory 112 after getting off the plane, so after he arrived at the 606 Institute, except for Hai Yide, the chief engineer who has been leading the organization in Shengjing, the others didn't even have any preparations.

"Mr. Chang didn't tell us before he came, let's pick up the ......"

An engineer who followed Haiyide touched his beard, his sideburns, which he had obviously not taken care of in many days, and glanced at the design and research room, which was almost covered with various materials and diagrams, with a somewhat embarrassed expression on his face.

Although the design of engines has been digitized to a considerable extent, this room is actually a place where several of their R&D groups meet.

After all, Hangfa is a complex system engineering, it is impossible to really get a few parts together like pinching plasticine, and the failed compressor design at the beginning of the turbojet 14 has proved that this kind of play is absolutely not feasible, so even if it is still in the early stage of the project, we still need to often communicate with each other under the leadership of the overall design team, so as not to deviate too much from the research and development direction of a subsystem.

And this process is often more convenient with paper materials, after all, there are no online working software these days.

"That's the outside, isn't it?"

Chang Haonan casually put aside a huge drawing covering two chairs, and then sat on one of them:

"Although I haven't been in Shengjing, since we are the same R&D team, we are a family, don't act like a welcome leader."

Because the design of aero engines involves a large number of complex numerical calculations, and the city with the most abundant supercomputing resources in the country is Beijing, and the compressor research center planned in the future is also in Beijing Airlines University, so in fact, a considerable number of R&D personnel are based in Beijing with Chang Haonan.

Moreover, he is also a front-line designer, and he has a deep understanding of the mental state of everyone in the process of the project, especially in the critical stage of starting and tackling key problems.

If the office is messy, let it be messy, and once it's tidied up, there will always be something that can't be found.

As the chief designer, he has been almost everywhere throughout the project, and there is no need to rely on nothing to show his presence like some leaders.

After everyone sat down, Haiyide quickly brought the topic back on track:

"Okay, now that we're almost all here, if you have anything to report or ask to Mr. Chang in person, you can just save the trouble of going to the capital on a business trip, hurry up and say what you should say, and ask what you should ask."

Usually although Chang Haonan is in BJ, he doesn't just leave Shengjing alone, each R&D direction has to submit a project progress report every week, and he will also give feedback at the first time, so although he hasn't been to the 606 Institute for two months, there is no such grand occasion where everyone has accumulated a bunch of questions and actively asked questions.

"Mr. Chang, let's report the situation on the combustion chamber first."

After a brief moment of silence, an engineer who appeared to be in his mid-fifties spoke first.

Yin Yongze, one of the several deputy chief designers of the turbofan 10, is also the person in charge of the research and development and design of combustion chamber technology.

He participated in the design of China's first annular combustion chamber in the turbojet 14 project, although in terms of paper performance, the design that is not yet mature is not much better than the past annular tubular combustion chamber, but because the flame cylinder is an integral annular cavity, the space utilization rate is higher, the outlet flow field is evenly distributed and the cooling pressure required is relatively small.

Simply put, the potential is greater.

It was precisely because of Yin Yongze's experience that Chang Haonan dared to hand over the combustion chamber, one of the three major parts of the core machine, to him.

"The last time I reported to you, we have set up the combustion chamber high-pressure test platform, and during this time we have also carried out some parametric design preparations, which is expected to compress the number of high-pressure tests to about half of the level in the past, and the next step is to start computational model development and parameterization system, but the combustion power we have determined now is a bit large, and the requirements for cooling intensity are very high, I wonder if the compressor can provide more 6%-8% of the inlet air flow?"

Yin Yongze said and slid a piece of information in his hand along the desktop to Chang Haonan.

The latter looked through it and found that it was a material for the parametric geometry modeling of an annular combustion chamber.

"The pre-treatment work is done well, in addition, I remember that when the calculation model was developed later, the atomization model can be done in addition to the standard centrifugal nozzle, and by the way, the structure of the centrifugal oil dumping pan can also be done."

Because the human understanding of the combustion process is still relatively unclear, so in the combustion aerodynamics and structure, numerical calculation can play a relatively small role, and the research basis for the combustion chamber structure is not as good as compressors and turbines.

"Throwing oil pans?"

Chang Haonan's request made Yin Yongze stunned:

"Our Design ......"

However, he was interrupted by Chang Haonan halfway through:

"Of course, the turbofan 10 is a big push to use centrifugal nozzles, but in the future jet power will definitely be popularized, such as cruise missiles and UAVs These places need small aero engines, the fuel supply pressure of the oil dump pan is low, not easy to block, the most important thing is cheap, just take advantage of the opportunity to lay a foundation by the way."

Compared with other aviation development researchers in China in this era, Chang Haonan's biggest advantage is not only to open up, but also to have a more long-term planning ability.

"Okay, we'll keep an eye on it then."

Yin Yongze opened the notebook in front of him and wrote down this request:

"That is always the thing, the matter of the intake flow ......"

"6%-8% is too much."

Chang Haonan immediately shook his head:

"Now the overall design level has basically determined the structure as a 2-8-1-1 structure or a 3-7-1-1 structure, so that the margin left for each stage is very small, 6% to 8% that is almost necessary to add an extra level of high pressure, definitely not."

"But the demand for cooling air flow on our side is really much greater, if not increased......"

Film cooling can be said to be a landmark technology in the history of aero engine development, but the use of gas for active cooling is not without cost, and these gases used for cooling cannot be used for propulsion, which is equivalent to the loss of a considerable part of the compressor power.

Therefore, although theoretically only the amount of cooling gas needs to be increased to achieve better results, in the actual aviation design, the problem of gas loss rate should still be taken into account.

If at least 6% of the combustion chamber wall is consumed, then the turbine with a higher cooling pressure is included......

Also play with a hammer.

Nearly one-fifth of the air sent in by the compressor is directly discharged by you, which may be acceptable for engines with output shaft power such as turboprops and turboshafts, but for turbofan engines, it is basically wasted.

And if you add another level of high pressure, it will become 3-8-1-1, which is not at all different from the current AL31F.

The performance of the AL31F is certainly adequate, but the potential is not.

After all, it was designed in the late 70s.

"What is the upper limit of your combustion chamber outlet temperature?"

The pre-turbine temperature (that is, the combustion chamber outlet temperature) of the turbofan 10 is set at 1200-1250 °C, which is a decision made by Chang Haonan himself, but the cooling system must leave a certain margin, and how much to leave is Yin Yongze's job.

"Leave a 5% margin, 1325°C."

This margin is, of course, calculated in accordance with the Kelvin temperature.

Immediately afterwards, Yin Yongze added:

"This cooling requirement is too high, we can only use groove cooling instead of the round hole cooling on the turbojet 14, and the demand for air flow will come up."

Now Chang Haonan finally knew what the problem was;

"Don't use groove cooling, my next plan is to study the high-efficiency forming hole cooling scheme of the turbine part, and replace the round hole with a special-shaped hole, which can theoretically achieve a similar effect to the slit cooling, and the amount of air will not increase, you will continue to calculate other structures according to 1325 °C, and the specific cooling scheme, and then I will develop the porous media model of the special-shaped hole."

Although the temperature at the outlet of the combustion chamber is undoubtedly the highest part of the engine, the final conversion of the energy of high-energy gases into mechanical work still depends on the turbine, which not only works in a high temperature and high pressure, but also needs to rotate at high speeds and withstand external overloads, so the requirements for materials and cooling technology are even higher.

If a cooling technique can be used on a turbine, then moving to the sidewall of the combustion chamber is generally not a big problem.

(End of chapter)