Genius is just the threshold for me!

Chapter 78: Conducting Supercombustion Tests at Institute 624

"Great, very effective."

Lin Dong was amazed for a moment, and then he was clearly excited.

If a breakthrough is achieved in third-generation single-crystal nickel-based alloys, not only can the J-20's engine problem be solved, but his subsequent aircraft development plans can also design and manufacture more powerful unmanned combat aircraft.

"These 239 sets of data..."

Lin Dong opened the attached data in the email, quickly glanced through it, and then frowned slightly.

"Of the 239 experiments, 127 showed crystal cracks shortly after they started, and 112 showed fractures and dislocations from the very beginning, with uncontrollable infiltration of impurities... This is a serious problem. Is the most basic approach flawed?"

Lin Dong recalled the materials science knowledge he had learned, as well as the relevant models of single-crystal materials, and quickly analyzed in his mind to find the problems behind these data.

The universe follows the law of conservation of momentum, and space has translational symmetry.

This law dictates that as long as the environment, technology, and processes are the same, experiments conducted in one place can be easily replicated in another.

All 239 groups of experiments encountered problems shortly after they began, a 100% commonality.

This means that either the direction of the entire experiment, as Lin Dong proposed—the Czochralski method combined with gradient solidification to control the temperature—is problematic, or there is a problem with the control of the entire underlying process.

"The basic direction is fine; the problem lies in the precision and stability of the manufacturing process!"

"Instability in the process leads to cracks and faults in the crystal during growth, while also creating opportunities for external impurities to seep in..."

ten minutes.

Lin Dong identified the common issues behind these data and typed a reply on the keyboard.

The crystal structure of third-generation nickel-based alloys is more complex, and the control of the growth environment is extremely demanding, requiring further improvement in process precision.

The lifting speed must be kept below 7 mm per minute, the fluctuation value of the lifting pause must be less than 7.6%, and the lateral sway must not exceed 2 micrometers.

The temperature gradient needs to be controlled more precisely, with the gradient range per centimeter controlled within 35°C. This can better promote stable crystal growth...

"This improvement would almost require replacing the entire set of equipment, which would be quite costly. I don't know if it will be taken into consideration."

Lin Dong looked at the improved parameters he had requested, shook his head, and replied to Wang Xingguo.

Through years of study, he has gained a relatively good understanding of the formal scientific research and experimental procedures.

Because of limited research funding, both official and private research institutions are very cautious about high-cost experimental plans.

Feasibility is often determined through multiple rounds of research and assessment, or by a decision made by a high-ranking figure; otherwise, it is not easily undertaken.

This is completely different from his own personal experiment, where he could use as much material as he wanted as long as his funds allowed.

Therefore, Lin Dong couldn't guarantee that Wang Xingguo would adopt this improvement plan when he relayed it to the project team working on the third-generation single-crystal nickel-based alloy.

"Finally finished today's tasks, now it's time for me to tinker with my own gadgets."

Lin Dong stretched, opened the design software, and entered three different twelve-digit passwords. A sophisticated and complex three-engine blueprint with an industrial mechanical and technological feel popped up.

Lin Dong zoomed in on the blueprint, found a blank space, and fell into deep thought.

He had a thorough understanding of the theory of scramjet engines.

He also had a clear idea of ​​the design of the scramjet engine.

However, he has been unable to find a perfect solution to the problems he encountered.

For example, one of the most basic questions is the mixing of fuel and air.

Whether it's a piston engine or a jet engine, fuel must be mixed with air before it's ignited.

The more evenly the fuel mixture is mixed, the better the fuel efficiency, the better the engine power, and the better the economy.

In conventional sub-gas engines, fuel mixing is not a major issue; it simply involves normal vaporization and injection into the combustion chamber.

At most, you might need to adjust the injection angle, injection position, injection volume, and particle size.

Although it may be complicated to handle, you can just refer to the theory and simulation model and follow the R&D and testing process. You will not encounter any insurmountable difficulties along the way.

However, this problem becomes extremely difficult when it comes to scramjet engines.

Because of the scramjet engine, the internal airflow is supersonic throughout, and the airflow itself has a pressure barrier that blocks the aviation kerosene from the outside.

In addition, the supersonic airflow has a shorter time to pass through the engine, resulting in a longer combustion delay for kerosene.

In this way, the kerosene doesn't have time to mix before it's sprayed out, resulting in ineffective combustion outside the engine.

Besides.

The airflow of the scramjet engine is slowed down by shock waves, resulting in an average static temperature of up to 1300 degrees Celsius.

If aviation kerosene is not mixed and burned immediately, it will also form carbon deposits due to high-temperature cracking and coking, which can clog the engine.

"The DART-AE team, which later researched scramjet engines and completed the test flight of the experimental aircraft, used hydrogen as fuel."

In addition, some research teams have adopted solid powder fuels…

Lin Dong carefully recalled some information reported in later generations.

Hydrogen is used as fuel because its molecules are small and easy to mix.

In addition, the low combustion delay allows for complete combustion before leaving the engine, and hydrogen does not pose a risk of coking or carbonization.

As for solid powder fuels, the energy released by combustion is several times that of kerosene.

The same thrust requirement requires injecting less fuel, which is equivalent to reducing the problems of fuel mixing and combustion delay.

However, neither of these two fuels is suitable for his brand-new Hot Shot.

Hydrogen requires storage tanks and has a low energy density per unit volume, making it suitable only for short-range aircraft and unable to meet his endurance requirements for the new Hot Air.

As for solid fuel, he adopted a three-engine combination. The first two turbines and the sub-fuel ramjet have slow airflow speeds. If the molten material after solid combustion cannot be ejected in time, the engine will be scrapped in just a few minutes.

"The problem of cracking and coking can be solved with cracked kerosene. The core issues are still mixing and combustion delay."

This adds resistance inside the engine, creating a shock wave that helps stir the kerosene molecules and increases the airflow delay time, allowing the kerosene to burn sufficiently.

However, the core of this problem lies in the control of the shock wave structure and range.

"If the range is too large, it will lead to excessive total pressure loss in the engine, causing the engine to stall; if the range is too small, it will lead to insufficient kerosene mixing..."

Lin Dong, unusually, took out paper and pen and focused intently on listing out formulas in fluid mechanics.

After carefully calculating and determining the parameters for more than ten minutes, I opened a new design interface and quickly designed and drew a simple supercharged stamping test device.

After labeling the various parameters of the device and the test parameters, Lin Dong opened Wang Xingguo's secure communication system and then... uploaded and sent the data.

[Lin Dong]: Godfather, please help me find 624 to do an overburning test and measure the inlet pressure, outlet pressure, and total pressure.

[Lin Dong]: Urgent!

This time, Lin Dong did not contact his father, Comrade Lin Weiliang.

Because in China, apart from Institute 624, which is specifically responsible for aero-engine simulation testing and provides test verification and pre-research support, there is probably no other laboratory that has the conditions and technology to conduct scramjet testing.

However, Lin Weiliang's connections and rank were not high enough to communicate with Institute 624 and ask them to prioritize the experiment.

P.S.: Waaaaah~ Dear readers, please give me motivation, I'm begging for monthly votes!

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