Automotive Black Technology Chapter 1505: : Smile, this is a turbojet aircraft!

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The sound of a gas turbine engine is quite unique, because the high-speed rotation of the turbine blades, coupled with the heat dissipation holes all over the surface of the single-crystal fan blades, will emit a sound similar to thousands of miniature whistles blowing rapidly at the same time.

At this time in the power laboratory, although the buzzing sound was still clear and clenched everyone's ears, it was not as harsh as expected. It was as if the air had been cut by many sharp blades, and in the rush, there was a trace of gentleness.

"Is this... the sound of a gas turbine engine? Even at idle speed, is it too low? Is it because of the small size of the engine?"

"No! I have seen the improved test of the Beishan OP-076 small turbojet engine currently used by our military target drones. Because the small gas turbine engine has a compact layout and a small fan blade area, the required heat dissipation holes are relatively large. , the noise is very high! It’s definitely different from this one!”

When the voice of Tianxing I sounded, everyone present immediately drew their attention away from Li Fanyu. Years of professional habits allowed them to quickly discover this aircraft model engine they called "model aircraft engine". Differences.

Wang Rui, who had been following Li Fanyu, couldn't help but feel happy when he saw everyone's reaction - a bunch of old haters!

What is Beishan? It's just a drone engine used to test interception missiles. How can a disposable thing be compared with our Tianxing I?

As an expert in dynamics and thermodynamics, Mei Yishu frowned and hissed slightly when he heard Tianxing I's voice.

However, considering that the Tianxing I was just running in and running, he just pricked up his ears and continued to listen carefully.

Li Fanyu was no longer in the mood to continue arguing with them. He took a deep look at everyone, then turned around and walked to the test bench data display board located in the corner of the laboratory.

The engine that is run for the first time after assembly, like the Tianxing I, cannot directly reach full horsepower and achieve high performance after starting. In order to comprehensively test the engine, it is necessary to run it according to the prescribed procedures. Based on the structural transmission and heat transfer analysis, it is a process of running in, idle and then gradually increasing the speed until the maximum power.

The running procedures of running-in are also divided into many types. But because Li Fanyu had high expectations for Tianxing I, he directly used the roughest running-in method, which is to advance the speed by two and retreat by one.

In a car, it is roughly the concept of two feet on the accelerator and one foot on the brake.

This running-in method is the best way to test the clearance between the engine rotor and the stator. Generally speaking, during such a test run, if the gap is too large, it is likely that the sound will be "scratching!" and "uh...".

But now, with the intervention of the program, the sound produced by Tianxing I is particularly comfortable.

"Dirty! Dirty!"

"Well..."

……

"Dirty!"

"Well..."

This kind of sound can only explain two problems-the internal layout of the engine is extremely compact. And...the vibration between the mechanical parts of the engine has been greatly suppressed due to the precision of a high enough coefficient!

However, as the running-in slowly ended and the engine entered the idle stage, the noise level increased but the noise remained much smaller than that of ordinary aviation engines. In the ears of a group of experts, it was heard again Something else!

"What is the structure of the turbine blade fan? What type of linkage shaft is used? How can the noise be so small?!"

This is Mei Yishu’s problem.

Obviously, with the tips of this expert, many people have realized the key point.

Hearing this question, Li Fanyu couldn't help but take another look at him. Xin said that although the old man's character may have some problems, he is still professional enough.

In the spirit of academic exchange, he decided to answer their questions;

"The fan blades of Tianxing I have no holes. Therefore, the noise is 25% smaller than that of the same type of single crystal fan blades. Three-axis linkage, main thrust fan, high-pressure turbine fan blade group and low-pressure turbofan group rotate coaxially and differently. . Moreover, the thirteen sets of turbofans in the low-pressure turbofan unit can operate at different speeds in a mechanically matched manner to coordinate the J-type combustion chamber duct. ”

"How is that possible!" On the spot, an aviation engineer exclaimed: "I can understand that the coaxial speeds are different. Even if your thirteen sets of low-pressure turbofans can match the high-pressure ducts by themselves, it is nothing more than slow speed. It is just a matter of reducing the noise and expanding the speed range to maintain the temperature of the combustion chamber and reach the working state as soon as possible. But without heat dissipation holes on the turbofan, how long will its lifespan be? With an operating temperature of one to two thousand degrees Celsius, what is the point of this thing without heat dissipation holes? Do you know that it is going to melt and deform?”

Huang Haixing fully agrees with this, "The problem of heat dissipation is first of all because the turbofan does not have holes. If the heat dissipation performance is not good, the life of the turbofan will be shortened sharply. Also, I will assume that this thing of yours costs more than 1,000 yuan. It won’t deform under temperatures of 100 degrees Celsius. It’s also a loss in terms of weight, and the speed can’t be increased. What is the thrust-to-weight ratio of your engine? 1:5 or 1:4?

Looking at the engineer who looked like his tail had been stepped on, and Huang Haixing who was showing off, Li Fan was foolishly happy: "Who told you that turbofans have to have holes drilled?"

"Also, is the operating temperature of more than a thousand degrees...very high?"

Huang Haixing blinked, "Isn't it high?"

"Ha!" Li Fanyu laughed, and patted Wang Rui next to him on the chest with his backhand, "Please introduce to Mr. Huang the red foot braking system used in our Xcar supercars and FE racing cars. Brake disc, what is the operating temperature? ”

"An average of 320 braking times in a race, and the peak temperature is 2110 degrees Celsius." Wang Rui, the chief technical engineer of Zhengxin Racing Team, gave the answer directly.

"How can a brake pad of yours be compared with a turbine fan blade! Is it the same? The turbine fan blades are rotating all the time!"

"So!" Li Fanyu spread his hands, "Tianxing I gave up the traditional single crystal blade and adopted a composite ceramic alloy + carbon fiber sandwich structure that is lighter, thinner and has better heat dissipation. Although there is no Drilling holes, but... Inside each blade fan, there are 800 through-type heat dissipation ducts! Compared with the fan blades you asked me to OEM, this one has a 30% increase in strength and weight per unit volume. Reduced by 20%, the heat dissipation is basically the same. ”

"As for the thrust-to-weight ratio, one to five, one to four...? I'm afraid you didn't come here to curse. This is a gas turbine aviation engine! Not a piston aviation engine! With such a low thrust-to-weight ratio, why should I build it? How about installing our W16 directly?"

While talking, the Tianxing I on the bench has ended its idle state. With the control of the test program, the working peak has begun to rise.

In the laboratory, the beeps gradually became louder and louder. Tianxing I finally got rid of its gentle side and became manic.

As the thick and solid test bench gradually made a creaking sound, several sets of data on the test data panel in front of Li Fanyu and others were also being refreshed rapidly!