Chapter 317 Coincidence
The test engineers present all turned their attention to the door.
"Surge sign?"
One of the people gently pushed the glasses on the bridge of his nose.
Now Chang Haonan's name has gained a certain reputation in the industry, so he hesitated a little at first.
But after repeatedly confirming that there was no obvious abnormality in the curve displayed on the computer screen, I decided to show my fearlessness of authority:
“But the data we just collected here are all normal... and no problems were found. Ah?”
“Yes, if the working curve is abnormal, fluctuations should be seen from the working Reynolds number and compressor flow rate...”
In the end, Xue Chishou made the final decision:
“No matter what, stop the engine first!”
Even if the engine is running at idle, it is still working under high temperature and pressure. If a problem does occur, the consequences will be serious.
“Yes!”
The chief engineer who was able to make the final decision spoke, and the somewhat overwhelmed atmosphere in the control room finally dissipated a little.
The roar in the test workshop gradually weakened and eventually became quiet.
A group of people looked solemnly at the fighter jet in the test workshop that glowed with metallic luster under the light.
"Export the data and let Chang Gong and Yang Gong lead people to analyze the situation first."
After a few seconds of silence, Song Wencong spoke first.
The only people who participated in the entire development of this active stability system were Chang Haonan and Yang Wei, so this matter naturally had to be completed by them.
"Old Xue, Old Song."
At this time, another man wearing a long-sleeved shirt and looking a little sick:
"Should we try driving again? After all, the comrades at the flight test station are right. We didn't observe any signs of failure just now."
Chang Haonan thought briefly in his memory, and then confirmed that he I have no impression of this face.
But being able to address the chief engineer and chief engineer in such a casual way obviously shouldn't be ordinary people.
However, Xue Chishou's first reaction when he turned around and saw the person coming was surprise, and then he hurriedly walked up to him:
"Old Yang? Why did you come back from the hospital again?"< br>
The visitor waved his hand to indicate that it was okay:
"Didn't I hear that you have started ground testing? How can my body be better even if I stay in the hospital? Why don't I come over and take a look."< br>
Xue Chishou sighed upon hearing this and opened his mouth but in the end he said nothing.
After a while, he turned sideways again, stretched out his palm to indicate the direction of Chang Haonan and introduced:
"Old Yang, this is..."
"I know Comrade Chang Haonan. I've heard about it in the hospital."
The man cheered up, walked up to Chang Haonan, looked at him for a few times, and then stretched out his hand:
< br>"My name is Yang Baoshu, Comrade Xiao Chang. A young talent is better than seeing it a hundred times."
This name suddenly made the latter realize it, and then he felt a little sore at the corners of his eyes——
Yang Baoshu, general manager of Rongfei, was diagnosed with advanced lung cancer in 1995, but still continued to work despite the illness, and died of the disease in 1999 on the original timeline.
"Mr. Baoshu, hello."
On this occasion, Chang Haonan couldn't say much else, so he stretched out his hands and shook the other person's hand tightly.
"Xiao Chang, I have just asked the on-site engineer to understand the situation. I don't mean to take it personally, but if no obvious signs of failure are observed, can we repeat the test again? ?”
After getting to know each other, Yang Baoshu quickly returned to the topic,
“If the problem just now can be reproduced, it will not be too late for us to stop the test and take it apart for inspection.”
If it makes sense, Yang Baoshu's suggestion is actually fine.
In fact, it is difficult to say who is right and who is wrong when it comes to fault identification. Problem recurrence is indeed a part of solving the problem. After all, the probability of problems with the sensor or algorithm itself is not small. A single test shows that Not too many questions.
But Chang Haonan had read the script, and he knew that this engine did have problems during testing in the previous life. And now that his active stability control system has called the police again, he definitely can't continue to take risks.
Maybe something will really go wrong next time the test reaches 40% or 50%.
Surge prediction can only predict surge caused gradually due to normal intake distortion. If the aircraft suddenly hits a bird or inhales a large foreign object, even the gods will not be able to save it.
"Don't worry, Mr. Baoshu, we haven't reached the stage of dismantling the aircraft yet."
Chang Haonan can only choose to stabilize the other party first,
"Now the test run The system integrates the latest technology I developed, which can predict the upcoming surge or rotational stall through small-amplitude disturbance waves with certain characteristics. The comrades at the test flight station will bring the data later, and I can analyze it on site. If hidden dangers can be found, targeted troubleshooting or improvements can be made. If no hidden dangers can be found, then restarting the test run will not take too long.”
Hearing that there is no need for extensive rework, Yang Baoshu finally concluded. He breathed a sigh of relief and didn't raise any objections.
About half an hour later, a staff member from the test flight station walked out of the test control room carrying a laptop.
"Chang Gong, the test data just now is all in it."
Chang Haonan took the computer and connected the power supply to the socket next to it.
Everyone in the room came behind him as quickly as possible and formed a tight semicircle.
In the end, a few people in the inner circle voluntarily squatted down so that everyone could see the small screen.
Everyone here is an expert in aerospace engineering.
Whether they believe Chang Haonan's statement or not, everyone wants to see what this surge sign is about.
After several rounds of data processing within the software, only a few curves are now left among the originally numerous and complex curves.
Those skilled in the art can see that what Chang Haonan did just now was to separate the components of the measurement signal at a specific frequency.
“Look here.”
Chang Haonan pointed to one of the curves and said,
“The component of the modal wave of the engine operating curve at the surge characteristic frequency was not there at the beginning. It suddenly appeared when the test went to 540 seconds, and then gradually It increased, and at the 580th second, it was monitored by the surge prediction system, and the throttle opening was forcibly closed. After 20 seconds, this component disappeared again."
"This... ”
Of course everyone can understand a curve, but many people still don’t understand why this curve is related to surge.
At this time, Yang Wei, who was also involved in the entire software development process, turned around and briefly introduced the basic working principles of the system to other colleagues,
"Let me explain, when the engine is far away from the surge boundary, the system has a strong attenuation effect on small random disturbances inside the system. At this time, even if there are some disturbances, they will be quickly wiped out and will not continue. Deterioration. As the engine stability margin decreases, the system's damping to small random disturbances also gradually decreases. When the stability margin is reduced to a certain extent, small random disturbances within the system will occur into a more stable frequency. Initial disturbance of the modal wave..."
"Starting from 580 seconds..."
Someone noticed the timestamp Chang Haonan just mentioned, and recorded it with another computer After comparing the test logs, he shouted in surprise:
"Wait a minute, Commander Zhou gave the 70% password at 570 seconds, that is to say, at 540 seconds, when the routine analysis began to show abnormalities, the program The flow valve should still stay at the 60% position!"
As soon as these words came out, a burst of discussion broke out among the surrounding people.
Obviously, it is not the action of pushing the throttle to 70% that induces the surge precursor, but the hidden danger existed earlier.
Alternatively, it is possible that the surge prediction logic of this active stability control itself has problems.
On the one hand, although Chang Haonan has now gained a certain degree of popularity, most people at the scene have not worked with him before, and hearing is not true after all.
On the other hand, the basic principles that Yang Wei just introduced are indeed quite complicated in mathematics. Most people can only understand them in general, and it is naturally difficult to follow them without a thorough understanding. I agree from the bottom of my heart.
Fortunately, several key persons in charge, including Xue Chishou and Song Wencong, had a deeper understanding of Chang Haonan. After a brief discussion, they ordered the suspension of this startup test.
Chinese people pay attention to getting off to a good start. The first trial ended in an anticlimactic manner. Although many people present obeyed the order, their emotions were still affected.
At this time, a loud voice sounded from the outside of the crowd:
"Well, there is no need to conduct an overall overhaul of the aircraft first. I can get into the air intake and take a look. The situation of fans and low-pressure compressor blades! ”
(End of this chapter)