Chapter 1079 I Have Calculated Everything

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

However, it didn't last long.

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

Essentially it is to illustrate the principle.

Even many structural details have been simplified.

You will understand it soon.

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

As for the regenerator, since its purpose is to utilize the residual heat of the exhaust gas, its design location 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 would be too abstract to design an additional resistance structure in the tail nozzle.

In fact, although there is no mass-produced model yet and it is not a turbofan engine, the United Kingdom, the United States and other countries have also designed to add regenerators to turboshaft/turboprop engines.

This doesn’t mean 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 simply represented by a module of an "intercooler unit".

But almost everyone wants to know what plan Chang Haonan is going to use 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 a university in Zhejiang Province.

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

The reason why I was invited here in the first place was largely because Academician Cen, a leading figure in the field of basic combustion, happened to be on a study tour abroad, and there were not many representative figures in the field of gas-solid multiphase flow and basic combustion.

I thought it was just a formality, but halfway through, I suddenly entered his professional field...

"Professor Chang."

Even when Fan Jianren was asking questions, he kept recording:

"For new-generation gas turbines such as the WR21 and my country's QC300, the regenerator is placed outside the main structure, while the main structure of the intercooler is divided into two parts, the inner and outer parts. Ethylene glycol aqueous solution is used as the intermediate medium to transfer heat from the onboard intercooler to the offboard intercooler."

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

Having said this, he hesitated for a moment.

I am not a professional in aeroengine design, so the following questions may seem like an outsider questioning an expert.

Moreover, he questioned Chang Haonan, an expert with a legendary experience.

But now that we have come to this, we can’t stop halfway.

"The intercooler duct you left on the diagram seems to only provide space for the cooling medium to flow, but does not leave room for the intercooler structure itself?"

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

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

After he finished speaking, perhaps because he felt that it was not convincing enough, he added:

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

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

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

No matter how ingeniously the intercooler and reheater are designed, they are still additional dead weight.

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.

This is obviously not good news for performance on paper.

However, many people present immediately changed their expressions.

Mainly they were comrades from the Gaofei Group next door who were attending the meeting.

Especially Liang Shaoxiu, his face turned pale——

The design of the Y-9 has been going on 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 you have to do is plug the PS90 or WS-20 into the interface that has been reserved.

Now tell them that they need to set up a separate cold and heat recovery equipment outside the aero-engine?

What's going on?

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

It is not a good idea to interrupt without warning.

Therefore, for a moment, the expressions on Liang Shaoxiu's face flashed like a kaleidoscope, 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 aero engines, and even the entire aviation industry, is a brand new topic for China.

Although 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 aero-engine project.

The idea of ​​specializing in specific products is still rooted in our minds.

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

"Professor Fan is right."

After some affirmation at the beginning, Fan Jianren, who was a little nervous at first, calmed down.

Then, he glanced in Liang Shaoxiu's direction:

"Placing some of the intercooling equipment outside the main structure can indeed reduce the difficulty of aeroengine design 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."

"Also, we don't need to use wordplay to demonstrate the performance of the product..."

In fact, Chang Haonan has been implementing this principle since he first participated in the WP-14.

Be it publicity or air show.

The engine performance he demonstrated was completely real, even deliberately restrained.

This answer undoubtedly eliminated Gao Fei's worries.

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

After a brief 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 structure diagram:

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

"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 partition heat exchanger to perform direct heat exchange between the cold and hot end airflows."

"!!!"

When he said this, almost all the audience in the conference hall sat up straight involuntarily.

Anyone who can sit in this meeting room today, even if they are non-professional leaders in charge, cannot be a complete layman.

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

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

However, this is not exactly the same as the design direction of the WS-10 core engine.

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

And on this basis, he was actually planning to take further action 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 impact of airflow is still the same, and the structure cannot be treated casually.

Even though Chang Haonan has rich experience and strong strength in this area, he cannot violate the laws of physics.

Although he had said before that he would not rule out cooperating with Rolls-Royce in order to gain access to overseas markets.

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

With Chang Haonan's style, it is impossible to delegate this part of the work to outsiders.

Soon, concerns were raised:

"Comrade Haonan, with our current material level, the design of the WS-10 is already at its limit. 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 spoken yet, it was clear from his expression that he had the same concerns.

Of course, there are also people who are full of confidence and think that Mr. Chang has created enough miracles and it is entirely possible that there will be one more.

However, his next answer was beyond the expectations of both parties:

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

"Ok?"

"what?"

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 space was reserved for adding a low-pressure compressor... and the boost ratio of the first version was too high. In order to take into account high-speed performance, the boost ratio was specially lowered..."

"..."

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

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

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

Chang Haonan himself just said it casually.

Therefore, the vast majority of people really didn’t think about it just now.

But now that they have been reminded of this, everyone has finally come to their senses.

So you were considered good at that time?