Chapter 1213 A big problem solved with a piece of paper
There is only one main sentence written on such a large piece of paper. If you put it aside in normal times, it would be a bit meaningless.
After all, when doing things in the academic circle, the title, abstract, introduction, and text and conclusion citations should be complete, and the six elements should be complete, just like that.
Even people at the level of the founder of the industry generally do not break this rule.
But considering that the Haofei Group is currently struggling with the issue of the flow field characteristics of the bomb bay, this sentence can be regarded as a timely help.
What's more, there is Chang Haonan's signature in the lower right corner of the white paper.
There was only a moment of hesitation in Jiang Jianjun's eyes, and then he made a decision in his heart.
And Qiao Chenqing, who was next to him, had already understood the meaning of the sentence on the paper:
"Is this... the solution to the problem we just discussed?"
"Yes."
Although he was asking questions knowingly, it was the leader who spoke after all. Jiang Jianjun quickly stopped preparing to ask someone to do something and gave an affirmative answer.
Qiao Chenqing couldn't help but show a shocked expression.
Although he had heard about Chang Haonan's deeds more than once, seeing it with his own eyes today still made him feel that it was a bit exaggerated.
You must know that the other party has not directly intervened in the modification of this Tu-160.
Now, suddenly a letter was sent with the design parameters of the verification bomb, and it happened to meet the biggest trouble faced here?
The last time Qiao Chenqing heard about this kind of thing was when he was a child. The storyteller talked about the tips in "The Romance of the Three Kingdoms"...
"Then... how feasible is it?"
At this time, he couldn't care less about continuing to act like a leader and quickly asked.
Jiang Jianjun was stunned for a moment, and then replied helplessly:
"Chief, I just saw this letter a few minutes ago, how could I know right away..."
At this time, Qiao Chenqing also realized that he was a little anxious, so he prepared to add a few words to avoid putting too much pressure on the other party.
But before he could speak, he heard Jiang Jianjun change the subject:
"However, in principle, if the inclination angle of the rear wall of the embedded weapons bay is large enough, the structure of the bomb bay is no longer a typical cavity in terms of aerodynamics, and the problem will be solved naturally... Just rely on the inclination angle to change To achieve this effect, an angle of about 70° is required, which is equivalent to directly occupying half or more of the effective space in the weapons bay, and is not engineeringly operable.”
“As for combining it with a leading edge spoiler…”
The latter showed a little shame on his face:
"It is indeed an idea that we have not tried before."
Qiao Chenqing naturally wouldn't criticize the other party for this kind of thing, and what's more, what he is most interested in now is not the issue itself.
"Comrade Jianjun, you have worked in the aviation industry system for a long time, so I would like to ask an additional question..."
He softened his tone slightly:
"Academician Chang...did he often do this before?"
"What I mean is that although people are far away, they can still guide the specific work."
Jiang Jianjun scratched his head, his expression a little twisted:
"The last time I worked on a project with Academician Chang was in 1997. At that time, we were going to use the H-6 to modify a water spray test machine to simulate icing... The task was not complicated, and Academician Chang didn't seem to have done it at the time. I graduated, so I don’t have too deep feelings.”
"But according to Mr. Liang, who was transferred from Nanzheng after the merger, it seems that it is indeed not much different..."
For a moment, neither of them knew what to say.
Then, there was another silence.
In the end, it was Qiao Chenqing who took the lead to break the deadlock:
"Then the next step is to conduct flight tests again according to the ideas given by Academician Chang?"
Seeing that the topic finally returned to something he was familiar with, Jiang Jianjun breathed a sigh of relief:
"That's not true."
He shook his head:
"Even with the suggestion given by Academician Chang, we cannot directly take the risk of flying on the aircraft. We must first conduct numerical simulations and wind tunnel tests to at least verify the feasibility and safety of this solution."
In fact, when Qiao Chenqing asked this question, he was already ready to stand up and end the survey.
But after hearing the answer, he sat back abruptly, with a hint of curiosity in his eyes.
In his early years, when he was serving in the Air Force of the Beijing Military Region, he heard a report from the Aviation Industry Group, which mentioned the use of computer simulation technology to improve test flight accuracy and reduce unnecessary test flight time to some extent.
So some ideas about this:
"Numerical simulation...will the results be available soon?" Jiang Jianjun raised his eyes slightly. Seeing Qiao Chenqing's expectant face, he immediately guessed that the other party wanted to stay and see the results with his own eyes, and he smiled bitterly——
Numerical simulation does save time to some extent.
But that's relative to test flights.
Actual operation is still affected by the complexity of the simulated system itself, as well as the algorithm and theoretical skills of the operator.
The leader's itinerary has been arranged, and he will only stay here for two days at most.
If Academician Chang himself were here, it might still be time to come up with concrete results.
But let yourself do it...
That's really a bit embarrassing.
Fortunately, Jiang Jianjun had a quick mind and quickly thought of an alternative.
So he nodded firmly:
"I'm afraid it will take some time to reach specific quantitative conclusions, but if it is just a qualitative verification of feasibility, it really won't take too long..."
Sure enough, Qiao Chenqing immediately beamed with joy:
"Well, I'll stay one more night in Haojing so that I can bring back a more accurate situation to Jun Wei!"
……
After temporarily seeing off Qiao Chenqing and his party, assistant He Haiqiang, who had been following him without speaking a word, came forward with an expression as if he had eaten bitter gourd:
"Mr. Jiang, with a little more time in this day, I can really..."
Halfway through, he was interrupted by Jiang Jianjun waving his hand:
"It's just a feasibility verification. Since Academician Chang has even given out the direction of solving the problem, we can't let things slip too far..."
He said and picked up the white paper from the table with only one sentence written on it:
"Xiao He, please remember it."
He Haiqiang jumped up, quickly sat next to him, and spread the notebook under his arm on the table.
"Continue to use the transient conservation control equation that we are more familiar with, but considering that this problem contains large-scale detached separation vortices and there are wall condition restrictions, so the Reynolds average method is used in the boundary layer near the wall, using The turbulence model simulates the small-scale pulsating motion, and on the far wall surface, the scale parameter in the dissipation term of the turbulence model is replaced by the product of the grid scale and the solution of an ordinary differential equation..."
"The entire model uses a partitioned structured grid, which is divided into 22 areas in total. The area near the missile body uses an O-shaped structural grid, and the head and missile body each contain five zones..."
"..."
After determining the next step of work, the entire project team started operating with unprecedented efficiency.
And when Qiao Chenqing returned to the Haofei Group the next morning, in addition to Jiang Jianjun, whose eyes were bloodshot, what appeared in front of him were several pages that smelled of ink, which had obviously been printed not long ago. Data distribution chart.
"The results are out yet?"
He hurriedly took two steps forward and came to several drawing boards with results posted on them.
"That's right, Chief."
Jiang Jianjun cheered up and pointed to the first chart on the far left:
"You see, we set up five disturbance devices with a height of 36mm, a width of 10mm, and a length of 450mm on the front edge of the bomb bay, and tested the rear wall inclination angles of 0°, 15° and 30° respectively. The results show that in the horse bomb The cabin length-to-depth ratio is 12 and the Mach number Ma=1.8 Under this condition, not only the maximum value of the yaw moment outside the bomb bay was reduced by 12%-27%, but the total sound pressure level of all measuring points in the bomb bay was also reduced by 1.0-1.4dB, which is equivalent to the same time. Improved airflow conditions outside the cabin and vibration conditions inside the cabin.”
"Although these two numbers are not enough to completely solve the problem, the current results are only the initial values we selected based on experience. There is still a huge room for optimization in the future... More importantly, the leading edge perturbation device can Acting as structural reinforcement, it will hardly affect the effective volume of the bomb bay itself. When the bomb bay door is closed, it will not have a negative impact on the radar reflection area, so..."
Hearing this, Qiao Chenqing couldn't hold back his emotions for a moment and directly took over the second half of the sentence:
"So, the same idea can be used directly in the bomb bay of a stealth aircraft?"
"Exactly."
Jiang Jianjun’s face has long since lost its sleepiness:
"We compared this design idea with the shallow cavity bomb bay of the F22 fighter jet and the S37 demonstrator aircraft, and found that the United States and Russia should have adopted similar technical solutions, so it is not easy to tell the clues from the appearance alone... ”
"As for the principle of action, we speculate that a series of high-frequency vortices are generated when the airflow passes through the metal strips. The frequency of these vortices is much greater than the frequency of the noise loop itself, which can enhance the mixing of the airflow in the shear layer and destroy the large vortex structure. And absorb the energy of the shear layer, thereby destroying the loop of noise generation to a certain extent..."
Qiao Chenqing naturally didn't understand the specific technical content.
But he didn't dwell on the details.
I just took a deep breath slowly and scanned the drawing boards in front of me again:
"It seems that Academician Chang's piece of paper really solved a big problem..."
(End of chapter)