Chapter 1079 I Have Already Calculated Everything

The picture thrown by Chang Haonan once again made the scene quiet down.

However, it didn't last too long.

After all, a 3D schematic diagram is just a schematic diagram after all.

It is essentially to illustrate the principle.

Even many structural details have been simplified.

You can see it quickly.

Compared with conventional turbofan engines, the most important change is the addition of an intercooler between the inner and outer ducts.

As for the regenerator, because the purpose is to utilize the exhaust residual heat, the design position is much simpler.

It can be installed directly behind the exhaust cone.

Of course, although Chang Haonan drew this part separately in the picture, anyone with a discerning eye can see that it must be combined with the inner wall of the tail nozzle in engineering.

Otherwise, as a jet engine, it is too abstract to design an additional resistance structure in the tail nozzle.

And in fact, although there is no mass-produced model yet and it is not a turbofan engine, the United Kingdom and the United States have also designed a regenerator on the turboshaft/turboprop engine.

It's not that Chang Haonan will definitely refer directly to foreign experience.

It's just that everyone has a basic concept.

The main problem is the intercooler.

In the figure, it is only represented by a module of an "intercooler unit".

But almost everyone wants to know what plan Chang Haonan is going to adopt to implement it...

When the topic transitioned from the overall plan to specific technical issues, the enthusiasm of the participants in speaking gradually increased.

For example, the first person to ask questions this time was an expert sitting slightly at the back of the conference room.

Fan Jianren, a professor from Zhejiang University.

In fact, his main research direction is not aeroengine, but engineering thermal physics.

The reason why he was invited here in the first place was largely because Academician Cen, a leader in the field of basic combustion, happened to be visiting abroad, and there were not many representatives in the field of gas-solid multiphase flow and basic combustion.

I thought it was just a formality, but I didn't expect that halfway through, I suddenly entered his professional field...

"Professor Chang."

Even when Fan Jianren was asking questions, he didn't stop recording:

"Like WR21, and of course, the new generation of gas turbines such as my country's QC300, all place the regenerator outside the main structure, and the main structure of the intercooler is divided into two parts, inside and outside, and then use ethylene glycol water solution as an intermediate medium to achieve heat transfer from the on-board intercooler to the off-board intercooler."

"But for aircraft engines, even if the high bypass ratio turbofan engine may not be very sensitive to its own weight, the use environment still determines that it cannot install too complex accessories outside the main structure, and if it is completely designed inside the engine..."

Speaking of this, he hesitated for a moment-

He is not a professional in aeroengine design, and the next question seems to be a layman questioning an expert.

And it is questioning an expert like Chang Haonan with a legendary experience.

But the words have come to this point, and it is impossible to stop halfway.

"The intercooler duct you left on the diagram seems to only provide space for the flow of cooling medium, but no space for the intercooler structure itself?"

As soon as Fan Jianren finished speaking, while Chang Haonan was still organizing his words, others followed up with their opinions:

"In fact, given the characteristics of passenger aircraft and transport aircraft, it is not impossible to install some intercoolers outside the aeroengine... I mean, these types of aircraft have relatively ample innate space and do not have very strict requirements on aerodynamic shape."

After saying that, perhaps he felt that he was not convincing enough, and he specially added:

"And this can also improve the thrust-to-weight ratio of the turbofan 20 to a certain extent..."

After all, it was just a launching ceremony for project approval, so the scene still had the meaning of technical discussion.

And the last point really touched the hearts of many people.

No matter how exquisitely designed the intercooler and regenerator are, they are always extra dead weight.

And China's thrust-to-weight ratio standard is basically close to the most honest French standard, so this part of the weight will be added to the denominator.

It is obviously not good news for paper performance.

However, many people present changed their faces immediately.

They were mainly comrades from the neighboring Gaofei Group who were listening.

Liang Shaoxiu, in particular, turned pale.

The design of the Y-9 has lasted for two years. Now the aerodynamic design has been basically completed, and the structural design has entered the optimization stage, which is basically the end.

All they have to do is plug the PS90 or WS-20 into the interface that has been reserved long ago.

Now they are told to set up a cold and heat recovery device outside the aeroengine?

What are you doing?

But according to the regulations, they can only be regarded as customer representatives, and their speaking priority in the venue is not high.

It is not a good move to interrupt rashly.

Therefore, for a while, the expressions on Liang Shaoxiu's face flashed like a revolving lantern, which was very exciting.

Fortunately, Chang Haonan on the stage did not think for too long.

In fact, he understood the thinking of the person who expressed his opinion later.

The commercialization of aeroengines, and even the entire aviation industry, is a brand new topic for China.

Although the aviation power and aviation industry have been separated for four years, for most of the older generation, this has only improved the status of the aviation engine project.

The idea of ​​specializing in engines for special purposes is still rooted in their minds.

This is exactly what Chang Haonan hopes to change through the AE1500 project.

"Professor Fan is right."

The affirmation at the beginning stabilized Fan Jianren, who was a little nervous.

Then, he looked at Liang Shaoxiu's direction:

"Placing some intercooling equipment outside the main structure can indeed reduce the design difficulty of the aeroengine to the greatest extent, but this will greatly reduce the adaptability of the engine, which will not only bring additional troubles to the aircraft design field, but also be detrimental to future market expansion."

"Moreover, we don't need to use word games to reflect the performance of the product..."

In fact, Chang Haonan has been implementing this principle since the beginning of the participation in the turbojet 14.

Whether it is publicity or air show.

The aeroengine performance he showed was completely real, and even deliberately restrained.

This answer undoubtedly eliminated the worries of Gaofei.

But on the other hand, Fan Jianren's question just now has a second half...

After a short pause, Chang Haonan continued to explain:

"In order to reduce the impact of adding an intercooler on the structure and flow path of the turbofan engine, we plan to integrate the intercooler with the turbofan engine and transform the structure of the turbofan engine itself."

At the same time, the PPT was turned to the next page.

The above is a slightly abstract structural diagram:

"Considering that the intercooler must be set after the fan and before the combustion chamber, the only relatively simple structure in this part that can be significantly improved is the stator of the compressor..."

"Therefore, my final plan is to divide the intercooler into multiple units and set them in the stator structure, add necessary accessory pipes to connect the intercooler units with the turbofan engine components, and design a separate duct in the engine outer duct to install the intercooler units. Use a wall-type heat exchanger to directly exchange heat between the cold and hot air flows."

"!!!"

When he said this, almost all the audience in the venue sat up straight involuntarily-

People who can sit in this venue today, even if they are non-professional leaders in charge, cannot be pure laymen.

Everyone knows that in order to meet the needs of high boost ratio and wide surge margin, the blade structure and shape design of the compressor have almost reached the current limit.

Moreover, the high bypass ratio turbofan engine does not need to consider supersonic conditions, so the boost ratio is almost literally the higher the better.

This is not exactly the same as the design direction of the WS-10 core engine.

Although Chang Haonan has added a fan that is much larger than the same level of products to the AE1500, the design space left for the compressor is still not optimistic.

On this basis, he is actually preparing to further work on the stator?

You know, although the stator does not need to rotate at high speed and does not need to bear huge centrifugal force, the airflow impact is not less, and the structure cannot be treated casually.

Even if Chang Haonan has rich experience and strong strength in this regard, he can't violate the laws of physics.

Although he said before that he would not rule out cooperation with Rolls-Royce in order to gain foreign markets.

But the intercooling and heat recovery design is the core competitiveness of the AE1500, even more core than the turbine of the Trent 900.

With Chang Haonan's style, it is impossible to entrust this part to outsiders.

Soon, someone raised concerns in this regard:

"Comrade Haonan, with our current material level, the design of the WS-10 is already quite extreme, and to optimize the structure and aerodynamics of the stator blades at the same time on this basis...isn't the risk too great?"

Although Liu Zhenxiang, who was sitting in the front row, had not yet spoken, from his expression, he obviously had the same concerns.

Of course, there were also people who were full of confidence and felt that General Chang had created enough miracles, and it was entirely possible to have one more.

However, his next answer was unexpected by both parties:

"Actually... there is no need to optimize the aerodynamics..."

"Hmm?"

"Ah?"

Chang Haonan did not continue immediately, but took a sip of water slowly before explaining:

"I don't know if you remember that when the WS-10 project was launched, I said that the overall structure was originally designed according to the standards of the fourth-generation engine, and reserved space for adding a low-pressure compressor... and the boost ratio of the first version was too high. In order to take into account the high-speed performance, the boost ratio was specially lowered..."

"..."

Including Liu Zhenxiang, the expressions on the faces of several senior experts in the front row gradually changed from confusion to shock, and then from shock to enlightenment.

The matter of deliberately reducing the boost ratio was indeed mentioned back then.

However, at the time of WS-10, this could only be regarded as an episode.

Chang Haonan himself just said it casually.

Therefore, most people did not remember it just now.

But now that they were reminded of this, everyone finally came to their senses -

So you were already good enough at that time?