The Military-industrial Scientific Research System of the Academic Master Chapter 435

Chapter 435: Ten times life span

 In the next two days, several more researchers working in related fields arrived one after another.

In fact, if you are in a country with a relatively good scientific research foundation, this kind of problem can be directly issued as a research topic in the name of the 606 Institute or the Science and Technology Commission, just like the wing flutter analysis for the M60 project. , let several research groups conduct it separately.

 In addition to competing with each other, maybe we can also come up with something else in the process.

 A lot of technology accumulation in first-mover countries actually comes from this -

 When I researched it, I didn't know what its use was, but at some point later I suddenly discovered that it was crucial to a certain field.

For example, the algorithm proposed by Chang Haonan at that time has now been applied in many fields such as construction, machinery, and energy, and has even become part of the national standard in some industries.

However, with China's current technological foundation, it would be a bit of a waste of time to do this.

 As a late-developing country, it is likely that you will get extra gains by taking a trip on a road that has not been traveled by anyone before you. However, if others have already walked through it, it is better to cross the river by feeling the stones.

What's more, the timetable set by Chang Haonan for Turbofan 10 does not allow for such slow progress.

 With the support of many professionals, the research speed has been obviously increased.

"In fact, with the development of elastohydrodynamic theory, our current capabilities can fully consider the role of elastohydrodynamic lubrication based on past quasi-static models, and more accurately calculate the rolling element/ring contact under oil lubrication. Zone oil film thickness and pressure distribution…”

Wang Qinli stood in front of a blackboard and was introducing his current research direction.

 “Professor Wang, wait...”

 Another professor Zhang Qinggang from Northwestern Polytechnical University asked while he was drinking water:

“Then how do you deal with the oil film drag force, and the ferrule control theory in the Jones model? If you want to perform dynamics or even pseudodynamics calculations, it is impossible to continue to use this assumption..."

Due to the relatively slow speed of information transmission in this era, although we occasionally met each other in the past, communication at the academic level was basically limited to publishing articles. After all, papers are a summary of research results, and after all, they are not as intuitive and comprehensive as face-to-face meetings.

 Especially for colleagues, many times the mistakes and iterations in the research process of a research group are more enlightening than the research results themselves.

 These things cannot be seen at all just by reading the paper.

Now Chang Haonan suddenly brought these elders together. Although the former himself has not expressed his position, their exchanges alone have already sparked a lot of sparks.

"The oil film drag force can be obtained by using the oil film thickness calculation formula combined with the Newtonian fluid model to calculate the shear stress on the contact surface, and then integrating it. The result we calculated is about 10%-20% different from the actual situation. There is a gap, but as a quasi-dynamics calculation, it can already play a guiding role in the general direction. "

Wang Qinli put down the thermos cup and continued to answer questions from his peers:

 “As for the Jones model…”

 He said with a playful smile, turned back and quickly drew a schematic diagram on the blackboard.

“A year ago, we really didn't have any better method, but now, we can use the displacement-deformation compatibility condition between the rolling element and the ring to determine the deformation and force of the rolling element and the ring, and solve the partial differential equation By obtaining the revolution and rotation speed of the rolling elements, the geometric relationships and load distribution inside the bearing can be obtained..."

“Of course I know this, but the working state of the bearing will have strong nonlinearity. How can I ensure that we can obtain a usable numerical solution?”

Zhang Qinggang can naturally understand what Wang Qinli means. In fact, considering the elastohydrodynamic lubrication theory is also the direction he is researching.

 But in engineering matters, many times it is not just a matter of theory.

 The result cannot be calculated, everything is equal to zero, and nothing works.

“Well... I have to mention Mr. Chang.”

As he spoke, the latter glanced at Chang Haonan, who was sitting on the other side of the classroom, lowering his head to record without saying a word:

“As one of the first users of our school to apply for trial use of TORCH Multiphysics, several colleagues have already solved many similar strongly nonlinear partial differential equation solving problems through its numerical solution module. One of the professors who does gear research and I Cooperation, and finally developed a new computing model, which is simply..."

 Subsequently, he spent more than ten minutes reporting his new results in the most concise language.

“Considering that I am not the only one who has contributed to this work, I tentatively decided to name this model the 'Ice City Model'.”

Wang Qin was very happy when he said this. Obviously, he was very happy to be able to show off in front of his old colleagues and old rivals.

   “…”     The muscles on Zhang Qinggang's face twitched slightly.

 Although there are objective factors, others are further ahead in similar research directions, so it's really hard for him to say anything.

However, Wang Qinli continued to make faces:

“So, it doesn't matter if Professor Zhang doesn't understand this aspect, just use our model to calculate...”

At this point, Chang Haonan, who was a little worried that the academic competition between the two old comrades would turn into a physics competition in front of him, felt that it was time to end this discussion.

 Otherwise, it may not end well.

 He put the notebook aside and stood up.

Wang Qinli consciously turned over the blackboard, then moved to Chang Haonan's side and sat back down.

“First of all, thank you very much for your discussion just now. It not only allowed me to determine the current development level of domestic high-speed bearings, but also gave me a lot of inspiration.”

 You still have to be polite first.

But immediately after the next sentence, he looked at Wang Qinli, who had just sat down.

“Professor Wang, your model is indeed a leap forward compared to past theories, but there are still several problems.”

"First of all, the Newtonian fluid assumption of the lubricant should produce a relatively large error in the calculation results when the sliding condition is severe, and when the bearing moves at high speed, the characteristics of the lubricant will also deviate from the ideal Newtonian fluid, so I personally feel that this The model should be more suitable for heavy-load and low-speed scenarios, which is exactly the opposite of the working condition of aircraft engine bearings we are trying to solve now.”

Wang Qinli was just showing off out of habit, and what Chang Haonan said was indeed correct:

“As expected of Mr. Chang, he hit the nail on the head. We developed this theory during the process of developing bearings for the heavy-duty turbine equipment produced by Bingcheng Boiler Factory.”

Zhang Qinggang, whose face was almost turning green, finally breathed a sigh of relief secretly.

 Seeing that the atmosphere was finally a little more harmonious, Chang Haonan turned around and quickly wrote a few key points on the blackboard:

“Bearings used in aerospace engines have to face extremely high temperatures during operation, and they must withstand huge external overloads along with the aircraft, so they are very different from the ordinary bearings you have studied in the past.”

“So our next research direction is mainly the following points. First, we consider the coupling nonlinear effect of the aero-engine rolling bearing and the squeeze film damper, regard the motion of the aircraft as the implicated motion of the rotor system, and establish a complex structure under maneuvering flight conditions. Flexible asymmetric rotor system dynamics model supporting nonlinearity…”

“Secondly, considering the damage failure of the outer ring of the intermediate bearing, study the impact vibration characteristics of the dual-rotor system of the intermediate bearing under the maneuvering load environment, and analyze the amplitude and frequency modulation of the impact vibration of the multi-rotor system by the rotor speed ratio, maneuvering load size, bearing damage span and rotor speed. Mechanism of action…”

 “Then…”

“Finally, based on the above theoretical and engineering foundations, and based on the idea of ​​damage tolerance, we carry out the optimization design of aero-engine bearings based on complex cycle conditions.”

After the introduction, Chang Haonan put down the chalk in his hand and looked at the professors who were still writing furiously with their heads down:

"Considering that the basic design of the turbofan 10 engine has not yet taken shape, we are temporarily designing it based on the Spey MK202. The relevant data will be provided by me. However, please note that this project involves confidentiality issues. If you want to bring When students participate, they must explain the situation to them in advance.”

“As for the goal, it is initially set to increase the service life of the three-point and four-point bearing sets to ten times the original!”

 “Ten...ten times?”

Hearing this goal, even Wang Qinli's hands shook and he almost threw the pen away.

As a purely mechanical part, bearings are generally considered to be difficult to make leaps and bounds. Their past research results have basically been improved by 30%-50%. Even if advanced foreign technology is directly introduced, it will be 2-3 times. s level.

 As a result, when he opens his mouth now, it is an order of magnitude?

Chang Haonan was not surprised by this reaction and just nodded lightly:

"Well, the current average life of these two parts is less than 300 hours. If it can be increased ten times, the parts and the whole machine can have the same life. In this way, a lot of time can be saved in the design just for the convenience of replacement. No added structure helps reduce the structural complexity and weight of the engine.”

“For the new generation of engines, this is a crucial part that must be broken through!”

 (End of this chapter)

Chapter end