In order to test the Tianxing I engine, Zhengxin Experimental Center specially purchased a system for testing aviation engine. However, due to the tight time, the purchased system is relatively old, although it does not delay the accuracy of the test results, but due to the calculation method, there is some delay in the display.

As the engine transitions from slow to slow, gradually increasing the rpm and climbing towards the peak, the values on the display panel of the test system are slowly changing.

At this time, TianxingI has entered the working range of the express train,It is located at the top of the display panel,A value that is refreshed by Youzaiyouzai,That is, thrust!

For an aviation engine, especially a civil aviation engine, you can't use a certain data to judge its performance.

What is a civil airplane? To put it bluntly, it's just a bus in the air. It's certainly good for the bus to run fast and the engine jets to pull a lot, but on the other hand, every minute the plane is in the sky and consumes a lot.

Therefore, for civil aviation development, good performance is the best, but if the performance is mediocre, but the economy is more significant, it is also an excellent power.

But what is most important when it comes to economics?

Thrust, of course!

What is thrust? It's about the same as the horsepower of a car engine.

The speed of an aircraft depends on the balance of its thrust, mass, and drag. When the thrust is greater than the drag, the aircraft accelerates, and the acceleration is equal to the thrust divided by the mass. Then, the velocity is equal to the integral of acceleration to time, since the greater the velocity, the greater the drag, and the drag force is proportional to the square of the velocity, so when the drag is equal to the thrust, the acceleration is zero and the velocity no longer increases.

Therefore, the thrust of the aviation engine determines the acceleration and maximum speed of the aircraft.

At this time, on the test panel, the latest refreshed thrust value has exceeded 30 kN!

"Oh my God! Am I mistaken? As soon as I entered the working area of the express train, the thrust reached ...... 30 thousand Newtons?"

"What's the matter, it seems to have entered the middle of the acceleration now, and the increase in thrust value will slowly decay as the speed increases. I remember that the target engine used by our military in the past can also reach 50 kN at the maximum peak speed. Even if this small aviation engine is a bit powerful, at best, it is the level of a target aircraft aviation engine. But...... To design and build such an engine with technical characteristics in such a short time, well...... Zhengxin is also not bad. ”

Immediately, some people were smiling on Tianxing I.

Listening to the comments of a few engineers who flew up, Li Fanyu felt a little unhappy.

What is it called, at best, it is a target aircraft flight development level? What is it called?

You're contradicting yourself, right?

What Lao Tzu worked so hard to pick up from the sixth-level car can be compared to those glamorous and cheap goods carried by the military's target aircraft?

Joke!

Now it's just entering the high-speed working zone, where is this?!

He cast a contempt for the tongue-chewing engineer just now.

But before Li Fan was foolish, someone immediately jumped out, pointed to the latest refreshed data, and gave the person just now a resounding slap!

"The military target aircraft you are talking about is a turbojet! This is a turbofan! Can it be the same?"

"Forehead ......" was poked, and the man's face was a little unbearable.

Indeed, most of the target aircraft engines currently used by the military are turbojet engines, and one is that the structure of this engine is relatively simple and the cost is low, which can reduce the cost of the target aircraft. The other is that the turbojet engine has a relatively low bypass ratio, which can make a larger thrust with the same volume as the turbofan engine.

It's just that because of the low bypass ratio of the turbojet engine, the fuel consumption is leveraged.

The man pondered for a while, then argued: "It depends on the bypass ratio and thrust-to-weight ratio, if the thrust is high but the bypass ratio and thrust-to-weight ratio are low, then it is meaningless." After all, airplanes are the most economical, unlike cars, running on the ground, no matter how powerful and fuel-consuming, there are gas stations to go to. In the sky, an aviation engine that only knows the output power but does not consider fuel economy has no use value. ”

At this moment, someone shouted: "Look! The data of the culvert ratio has been refreshed!"

“1:11？”

"Huh?!I'm not mistaken!!"

"Oh my God, how is it possible? The cross-section of the engine doesn't look big, how can it have such a high bypass ratio!?"

The bypass ratio is actually the ratio of the air flow rate of the outer duct of the turbofan aviation engine to the inner channel. The air of the inner duct enters the combustion chamber and mixes with the fuel, and the air of the outer duct does not enter the combustion chamber, but is mixed with the gas flowing out of the internal tract and discharged.

The air in the outer duct only flows slowly and at low temperature through the fan, and the inner duct discharges high temperature gas, and the average flow rate and temperature of the nozzle are reduced after the two gases are mixed, the lower flow rate brings higher propulsion efficiency and lower noise, and according to the principle of heat engine, lower temperature can bring higher thermodynamic efficiency.

To put it simply, the higher the bypass ratio, the higher the thrust-to-weight ratio and the better the fuel economy!

The bypass ratio is an important design parameter for turbofan engines, which has a great impact on the engine's fuel consumption rate and thrust-to-weight ratio. Different turbofan engines for different purposes should choose different bypass ratios, such as turbofan engines used in long-distance transport aircraft and passenger aircraft, and the bypass ratio range is generally 4~8. The bypass ratio of the afterburner turbofan engine selected by the air superiority fighter is generally less than 1, and even as small as 0.2~0.3.

It's not that the air superiority fighter doesn't want a higher bypass ratio, mainly because the cross-sectional area of the turbofan determines the level of the bypass ratio. And because of operational needs, air superiority fighters, which often do high-speed maneuvers and supersonic flights, need a more streamlined fuselage, so they can only reluctantly reduce the bypass ratio. From another point of view, for civil aviation technology, any air superiority fighter is an oil tiger!

At present, the general civil aviation turbofan engine, such as the turbofan aviation engine under General Electric, the general bypass ratio is controlled at 1; Around 8. It's not that I don't want to make it bigger, but because of technical reasons, if this value is too large, the cross-section of the engine will become too cumbersome, which will greatly affect the safety of take-off and landing.

On the other hand, Tianxing I, because of the relationship between the shape of the blade fan and the internal structure, on the premise of maintaining the overall proportion of the engine, the bypass ratio has been increased to 1:11!

This is terrifying!

Seeing this value, that is, such a value, all the engineers present at Shanghai Flying Company had only one word left in their hearts.

Capital...... Wear!