Genius of the Rules-Style System

Chapter 837: Chapter 442: Let Me Go Instead!_1

The core components of a turbofan engine are the combustion chamber, the high-pressure turbine, and the high-pressure compressor. Combined, they provide the driving force for the engine.

The combustion is the most fundamental source of power; the high-pressure turbine spins the entire engine by harnessing the force from the combustion chamber.

The high-pressure compressor has the most functions, operating under the power of the high-pressure turbine. It provides a high-pressure air source for the combustion chamber, as well as high-pressure air for pressurizing the aircraft cabin, cooling high-temperature components such as the turbine blades, and de-icing and anti-icing the air intake, among other uses.

Furthermore, a certain amount of power is transmitted from the high-pressure compressor rotor shaft through gears to operate various engine accessories, such as the lubricating oil pump, fuel pump, starter, as well as the aircraft’s generator and hydraulic pump, and so on.

The high-pressure compressor is located at the center of the turbofan engine and is also one of the most core components.

Beyond its various auxiliary functions, the core technology of the high-pressure compressor lies in its ability to provide a compression ratio and stability.

The high-pressure compressor needs to supply high-pressure air, which makes it an unstable component within the turbofan engine. Its stability determines the stability of the turbofan engine as a whole.

The stability of any mechanical device is of utmost importance, and to some extent, stability represents safety. For fighter jets, any engine issues during flight can be fatal.

The current prototypes manufactured by the Kunlun engine group have many problems, most of which are due to the instability of the compressor. Among those stability issues, "surge" is the biggest one.

Surge is a state.

The compressor’s airflow comes from the flight of the fighter jet. The speed and altitude of the flight determine the amount of airflow entering the compressor, creating instability at the "airflow input end." frёewebηovel.cѳm

With the constant changes in flight conditions and engine speed, the compressor must also withstand continuous changes. The faster and larger the airflow is, which is to say the faster the speed of the jet, the better. When decelerating, the problems become even greater. The decrease in airflow intensity leads to a reduction in compressor speed, and subsequently, the internal compression ratio drops. The pressure drop in the initial stages is not significant, but it becomes more noticeable in the latter stages.

This is when problems arise.

When the pressure drops, the volume of the gas increases, making the compressor’s rear air channels appear "too small." Airflow is obstructed, unable to be fully expelled, and the blades do not function normally.

As a result, the gas pressure undergoes pulsating fluctuations—now high, now low.

When the airflow entering the first few stages of the compressor moves rearward and cannot flow all the way through due to blocked passages, it will flow back forward. The reversal clears the blockage in the rear passages, and then the airflow is sucked back into the compressor. Again, as it tries to flow backward, it is blocked and reverses...

This continuous cycle of changes causes the airflow to surge back and forth within the compressor and exit the outlet with unstable pressures and speeds.

This is the engine "surge" issue.

When "surge" occurs, it’s accompanied by a sudden rise in temperature before the turbine and a loud noise. Damage to the internal blades is a minor issue, but more seriously, it can cause the engine to shut down.

When Zhao Yi set out to solve the compressor problem, the first issue to study was "surge." Compared to compressor performance, stability was much more important.

It’s like an algorithm that doesn’t run well due to being riddled with bugs; no matter how efficient it is, it’s meaningless. Only when the bugs are resolved can the performance be further improved.

"There are two designs in the Kunlun compressor that combat ’surge.’ One is the bleed valve, and the other is the adjustable stator blades," explained Yuan Haitao, holding a design diagram of the high-pressure compressor.

This is also the prevailing thought among most of the Kunlun engine group.

The bleed valve, simply put, is for venting air. When there’s uneven pressure inside the compressor, releasing some of the high-pressure gas naturally relieves much of the pressure.

The design of the stator blades, however, is much more complex. The compressor has two sets of blades: the impeller blades that are connected to the turbine shaft and boost pressure, and the stator blades that remain stationary. Every stage inside the compressor is made up of one impeller blade set and one stator blade set.

The impeller blades are responsible for compressing the air, while the stator blades reduce its speed.

As the high-pressure gas is slowed down, its pressure continues to increase. Step by step, a large amount of gas is accumulated in a narrow space, and the pressure becomes very high.

If the stator blades were to rotate slightly in response to the changing pressure during compression, the wind resistance would also change continuously. This could help stabilize the internal pressure variations and reduce the likelihood of ’surge’ occurrences. freewebnovel.cσ๓

Put simply, it’s akin to an object falling from the sky, intended to create an impact. Direct fall to the ground might cause damage, but falling on a spring reduces the chance of damage.

So the downside is also clear.

Movable stator blades have a counter-effect on the performance of the compressor, which reduces the compression ratio. The bleed valve has the same problem, as venting high-pressure gas also lowers the compression ratio.