Chapter 1079 I’ve figured it all out
The picture Chang Haonan threw out made the scene quiet again.
However, it did not last long.
After all, a 3D diagram is just a diagram after all.
Essentially it is to illustrate the principle.
Even many structural details have been simplified.
You will understand quickly.
Compared with conventional turbofan engines, the most important change is the addition of an intercooling duct between the inner and outer ducts.
As for the recuperator, because the purpose is to utilize the exhaust gas residual temperature, the 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 the engineering must be combined with the inner wall of the tail nozzle.
Otherwise, as a jet engine, designing an additional resistance structure in the tail nozzle would be too abstract.
And in fact, although there is no mass production model yet and it is not a turbofan engine, countries such as the United Kingdom and the United States have also designed designs to add regenerators to turboshaft/turboprop engines.
That’s not to say that Chang Haonan will definitely refer to foreign experience directly.
It’s just that everyone has a basic concept.
The main problem is the intercooler.
In the picture, it is only represented by a module of "intercooler unit".
But almost everyone wants to know what plan Chang Haonan is going to use to implement it...
When the topic transitions from the overall plan to specific technical issues, the speeches with the audience are heated. The enthusiasm has 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 aviation development, but engineering thermophysics.
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 conducting inspections abroad, and I really couldn’t find much in the field of gas-solid multiphase flow and basic combustion. A representative figure.
I thought it was just a formality, but in the middle of the session, I suddenly entered his professional field...
"Professor Chang."
Even when Fan Jianren was asking questions, the movements recorded on his hand did not stop:
“New generation gas turbines like WR21, and of course my country’s QC300, all place the recuperator outside the main structure. , and the main structure of the intercooler is divided into two parts, the inner and outer parts, and the ethylene glycol aqueous solution is used as the intermediate medium to transfer heat from the onboard intercooler to the external intercooler. "
"But the aerospace engine, Even though a large bypass ratio turbofan engine may be less sensitive to its own weight, the use environment still determines that it cannot install overly complex accessories outside the main structure, and if it is completely designed inside the engine..."
said At this point, he hesitated for a moment -
I am not a professional in aerospace design, and the next question seemed to mean that a layman would question an expert.
And he still questioned Chang Haonan, an expert with legendary experience.
But even though we have said this, we cannot stop halfway.
“The intercooling duct you left in the picture seems to only provide space for the cooling medium to flow, but does not leave room for the intercooler structure itself?”
Fan Jianren’s voice As soon as Chang Haonan landed, while Chang Haonan was still trying to organize his words, someone else immediately expressed his opinion:
“In fact, in terms of the characteristics of passenger aircraft and transport aircraft, it is necessary to install parts outside the aircraft engine. It is not impossible to install an air cooler...I mean, these types of aircraft have ample space and do not have very strict requirements on aerodynamic appearance.”
After finishing speaking, he may have felt that he was not convincing enough, so 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 the launching ceremony for project approval, so the scene still had the meaning of a technical discussion.
And this last point really touches the hearts of many people.
No matter how exquisitely designed the intercooler and regenerator are, they are still extra dead weight.
And China's push-to-weight ratio standards are basically close to the most honest legal standards, so all this weight will be added to the denominator.
Obviously not good news for on-paper performance.
However, there were many people present who immediately changed their expressions.
Mainly the comrades from the Haofei Group next door who were listening.
Especially Liang Shaoxiu, his face turned pale——
The design of the Yun-9 has lasted for two years. Now the aerodynamic design has been basically completed, and the structural design has also entered the optimization stage, which is basically the end.
Just wait to plug the PS90 or Turbofan 20 into the port that has been reserved for a long time, and you're done.
Now tell them that they need to set up another cooling and heating equipment outside the aviation engine?
What's going on?
But according to regulations, they can only be regarded as customer representatives, and their speech priority in the venue is not high.
Interjecting hastily is not a good idea.
Therefore, for a while, the expression 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 stance very well.
The commercialization of aviation development, and even the entire aviation industry, is a brand new topic for China.
Although the aerospace power and aviation industries have been separated for four years, for most of the older generation, this has only improved the status of the aerospace engineering project.
The idea of exclusive hair is still rooted in my mind.
And this is one of the current situations that Chang Haonan hopes to change through the AE1500 project.
"Professor Fan is right."
The words of affirmation calmed down Fan Jianren, who was already a little worried.
Immediately afterwards, he glanced in Liang Shaoxiu's direction:
"Placing some of the intercooling equipment outside the main structure can indeed minimize the design difficulty of the aircraft engine, but this will greatly reduce the adaptability of the engine. Not only will it bring additional troubles to the aircraft design field, but it will also be detrimental to future market expansion. "
"Moreover, we do not need to use word games to reflect the performance of the product..."
In fact, Chang Haonan has been implementing this principle since he first participated in the Turbojet 14.
Whether it’s publicity or air show.
The aircraft engine performance he demonstrated was completely realistic and even deliberately restrained.
This answer undoubtedly eliminates Hao Fei’s worries.
But on the other hand, there is still the second half of Fan Jianren’s problem just now...
After a brief pause, Chang Haonan continued to explain:
"For To reduce the impact of installing an intercooler on the structure and flow path of the turbofan engine, we plan to structurally integrate the intercooler and 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 installed after the fan and before the combustion chamber, the only structure in this part is relatively simple. The only thing that can be significantly improved is the stator of the compressor..."
"Therefore, my final plan is to divide the intercooler into multiple units and install them within the stator structure, adding the necessary The accessory pipeline connects the intercooler unit to the turbofan engine components, and a separate duct is designed in the engine outer duct to install the intercooler unit. A partition-type heat exchanger is used to conduct cold and hot end Airflow direct heat exchange! ”
When he said this, almost all the audience members in the venue sat upright involuntarily——
People who can sit in this venue today, even non-professional leaders in charge, cannot It could be something purely amateurish.
Everyone knows that in order to meet the requirements of high boost ratio and wide surge margin, the blade structure and shape design of the compressor have almost reached their current limits.
Moreover, the high bypass ratio turbofan engine does not need to consider supersonic operating conditions, so the boost ratio is almost literally the higher the better.
But this is not exactly the same as the design direction of the turbofan 10-core machine.
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.
On this basis, he is actually planning to take further action on the stator?
You must know that although the stator does not need to rotate at high speed or bear huge centrifugal force, the impact of the air flow is not small, and the structure cannot be treated casually.
Even if Chang Haonan has rich experience and strong strength in this area, he cannot violate the laws of physics.
Although he has said before that he does not rule out cooperation with Rolls-Royce in order to obtain foreign markets.
But the intercooling and heat recovery design is the core competitiveness of the AE1500, even more core than the Trent 900's turbine.
With Chang Haonan's style, it is impossible to delegate this part to outsiders.
Soon, someone raised concerns in this regard:
“Comrade Haonan, with our current material level, the design of the turbofan 10 is already quite extreme. Basically, optimizing the structure and aerodynamics of the stator blades at the same time...is the risk too great?”
Although Liu Zhenxiang, who is sitting in the front row, has not spoken yet, judging from his expression, he obviously has the same concerns.
Of course, some people are confident and feel that Mr. Chang has already created enough miracles and it is entirely possible to add one more.
However, his next answer exceeded both parties' expectations:
"Actually... there is no need to specifically optimize aerodynamics..."
" Huh?”
“Huh?”
Chang Haonan did not continue immediately, but took a sip of water slowly before explaining:
“I don’t know if you remember, I said when the turbofan 10 project was established that the overall structure was originally It is designed in accordance with the standards of the fourth-generation engine, leaving room for adding a first-stage low-pressure compressor... Moreover, the boost ratio of the first version of the plan was too high. In order to take into account 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 understanding. Enlightenment.
The matter of specifically lowering the boost ratio was indeed mentioned back then.
However, in the case of Turbofan 10, this could only be regarded as an episode.
Chang Haonan himself just said it casually.
Therefore, most people did not think of it just now.
But now that they have been reminded like this, everyone has finally come to terms with it——
So it turns out that you were just fine by then?
(End of this chapter)