Chapter 435 Ten Times Lifespan
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 solved directly in the name of the 606 Institute or the Science and Technology Commission, just like the wing flutter analysis for the MA-60 project. Send it out as a research topic and let several research groups work on it separately.
In addition to competing with each other, maybe you can also come up with something else in the process.
This is actually how a lot of technology accumulation in first-mover countries came about——
When the research came out, I didn’t know what the 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 to do this.
As a late-developing country, it is possible to gain extra rewards by taking a trip on a road that has not been traveled before. 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, with our current ability, we can fully consider the role of elastic hydrodynamic lubrication based on the past quasi-static model, and calculate more accurately the effect of oil lubrication. Oil film thickness and pressure distribution in the rolling element/ring contact area..."
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, academic communication was basically limited to publishing articles. After all, papers are a summary of research results, and they are not as good as face-to-face meetings. Intuitive and comprehensive.
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.
But these things cannot be seen by just reading the paper.
Now Chang Haonan suddenly brings these elders together. Although the former himself has not expressed his position, their exchange alone has 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. However, 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 rolling elements and rings to determine the deformation and stress of rolling elements and rings. Force, solve the partial differential equations to obtain the revolution and rotation speed of the rolling element, and then obtain the geometric relationship and load distribution inside the bearing..."
"Of course I know this, but the working state of the bearing will have strong nonlinearity. How to ensure that a usable numerical solution can be obtained?"
Zhang Qinggang can naturally understand what Wang Qinli means. In fact, considering elasticity Flow lubrication theory is also the direction he is studying.
But in engineering matters, many times it is not just theory that makes sense.
The result cannot be calculated, everything is equal to zero, and nothing works.
"Well... I have to mention Mr. Chang."
The latter said and glanced at Chang Haonan, who was sitting on the other side of the classroom, lowering his head to record without saying a word:
"As the first batch of users to apply for trial use of TORCH Multiphysics, our school already has several colleagues Through the numerical solution module there, many similar problems of solving strong nonlinear partial differential equations were solved. I cooperated with one of the professors who does gear research, and finally developed a new calculation model. To put it simply... …”
Afterwards, 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'."
Speaking of which Wang Qinli's eyes were beaming. 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 for him to end this discussion.
Otherwise, it might not end well.
He put the notebook aside and stood up.
Wang Qinli turned the blackboard over consciously, 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."
"The first is the Newtonian fluid of the lubricant. It is assumed that when the sliding condition is serious, there should be a relatively large error in the calculation results, and when the bearing moves at high speed, the characteristics of the lubricant will also deviate from the ideal Newtonian fluid. Therefore, I personally feel that this model should be more suitable for heavy-load and low-speed applications. This scenario is exactly the opposite of the working condition of the 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 no problem:
"As expected of Mr. Chang, he hit the nail on the head. We developed this theory in the process of developing bearings for the heavy-duty turbine equipment produced by Bingcheng Boiler Factory."
My face almost turned green. Zhang Qinggang 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:
"During the working process of bearings used in aerospace engines, Firstly, it has to face extremely high temperatures, and secondly, it has to withstand huge external overloads together with the aircraft, so it is very different from the ordinary bearings that you have studied in the past."
"So our next research direction. The main points are as follows. First, consider the coupling nonlinear effect of the aeroengine rolling bearing and the squeeze film damper, regard the motion of the aircraft as the involved motion of the rotor system, and establish a flexible asymmetric rotor with complex structure supporting nonlinearity under maneuvering flight conditions. System dynamics model..."
“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, based on the idea of damage tolerance, the optimization of aeroengine bearings based on complex cycle conditions was carried out Design work."
After the introduction, Chang Haonan put down the chalk in his hand and looked at the professors who were still writing with their heads down:
"Considering the performance of the turbofan 10 engine. The basic design has not been finalized yet. We are temporarily designing based on Sibei MK202. The relevant data will be provided by me. However, please note that this project involves confidentiality issues. If you want to bring students to participate, you must inform them in advance. Explain the situation.”
"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?"
Hear this The target, even Wang Qinli, had his hands shaking and 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. That is 2-3 times the level.
The result is that now he opens his mouth to an order of magnitude?
Chang Haonan was not surprised by such a reaction, and just nodded lightly:
"Well, the average life of these two parts is currently less than 300 hours. If it can be increased ten times, the parts and The whole engine has the same life, so that many structures that have to be added just for the convenience of replacement can be omitted during design, which is beneficial to reducing the structural complexity and weight of the engine. "
"For the new generation of engines. Say, this is a crucial part that must be broken through!”
(End of this chapter)