Automotive Black Technology Chapter 1506: ：Capitalized service!

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

As the engine switches from idle and gradually increases the speed towards the peak value, the values ​​on the display panel of the test system are also slowly changing.

At this time, Tianxing I has entered the express working area. At the top of the display panel, a value that refreshes leisurely is the thrust!

For an aviation engine, especially a civil aviation engine, you cannot use a certain piece of data to judge its performance.

What is a civil aviation aircraft? To put it bluntly, it is just a bus in the sky. It is certainly good for a bus to run fast and have more engine power to pull it, but on the other hand, every minute the plane is in the sky consumes a huge amount of money.

So for civil aviation engines, good performance is the best, but if the performance is mediocre but the economy is relatively significant, it can be regarded as an excellent driving force.

But if you put aside economics, what is the most important?

Of course it’s thrust!

What is thrust? In fact, it is about the same horsepower as a car engine.

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

So the thrust of the aircraft engine determines the acceleration and maximum speed of the aircraft.

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

"Oh my God! Did I see it wrong? Just after entering the express working zone, the thrust reached... 30 kilonewtons?"

"What's the point? It seems that we have entered the middle stage of acceleration now, and the increase in thrust value will slowly decrease as the speed increases. I remember that the target drone engine used by our military before had a thrust of It can also reach 50 kN. Even though this small aircraft engine is a bit powerful, it is at the level of a target aircraft aircraft engine. However... to design and manufacture such an engine with technical characteristics in such a short period of time. Hmm... Zhengxin is not bad. ”

Immediately some people began to comment on Tianxing I.

Li Fanyu felt a little unhappy as he listened to the comments made by several Shangfei engineers.

What does it mean to be at the aviation level of a target drone at best? What do you mean by not bad?

What you said is contradictory, okay?

Can the things I worked so hard to pull off from the six-level car be comparable to those **** **** carried by the military’s target drones?

Joke!

We have just entered the high-speed working zone, where are we? !

He showed royal contempt for the nagging engineer just now.

But before Li Fanyu could respond, someone jumped out immediately, pointed at the latest updated data, and gave the person a loud slap in the face!

"The military target aircraft engine you mentioned is a turbojet! This one is a turbofan! Can it be the same?"

"Um..." After being poked, the man looked a little confused.

Indeed, most of the target drone engines currently used by the military are turbojet engines. One is that the structure of this engine is relatively simple and low-cost, which can reduce the cost of the target drone. The other is that the bypass ratio of the turbojet engine is relatively low, and it can produce greater thrust with the same volume as the turbofan engine.

However, because of the low bypass ratio, the turbojet engine consumes a lot of fuel.

The man thought for a while and argued: "Let's look at the bypass ratio and thrust-to-weight ratio. If the thrust is high but the bypass ratio and thrust-to-weight ratio are low, it doesn't make much sense. After all, the aircraft requires the best. It is economical, unlike a car. No matter how powerful it is on the ground and how much fuel it consumes, there are gas stations where you can go. In the sky, an aircraft engine that only knows its power output but does not consider fuel economy is of little use. value."

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

"1:11?"

"Huh?! I read that right!!"

"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 air flow in the outer duct and the inner duct of the turbofan aircraft engine. The air from the inner duct enters the combustion chamber and mixes with the fuel, causing combustion to do work. The air from the outer duct does not enter the combustion chamber, but mixes with the gas flowing out of the inner duct and is discharged.

The air in the outer duct only passes through the fan at a slow flow rate and is at low temperature, while the inner duct discharges high-temperature gas. The mixture of the two gases reduces the average flow rate and temperature of the nozzle. The lower flow rate brings higher propulsion efficiency and lower noise, and according to the principle of heat engines, lower temperatures 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 of a turbofan engine, which has a great impact on the engine's fuel consumption and thrust-to-weight ratio. Different bypass ratios should be selected for turbofan engines for different purposes. For example, for turbofan engines used in long-distance transport aircraft and passenger aircraft, the bypass ratio range is generally 4 to 8. The bypass ratio of the afterburning turbofan engines used in air superiority fighters is generally less than 1, and can even be as small as 0.2 to 0.3.

It's not that air superiority fighters don't want a higher bypass ratio, it's mainly because the cross-sectional area of ​​the turbofan determines the bypass ratio. Due to combat needs, air superiority fighters that often perform high-speed maneuvers and fly at supersonic speeds need a more streamlined fuselage, so they can only reluctantly lower the bypass ratio. To put it another way, for civil aviation technology, any air superiority fighter is a fuel tiger!

At present, the general bypass ratio of common civil aviation turbofan engines, such as those produced by General Electric, is controlled at around 1;8. It’s not that we don’t want to make it bigger, but because of technical reasons, if this value is larger, the engine cross-section will become too bulky, which will greatly affect the safety of takeoff and landing.

Looking at Tianxing I, on the other hand, due to the relationship between the shape of the blade fan and the internal structure, the bypass ratio has been increased to 1:11 while maintaining the overall proportion of the engine to be coordinated and narrow!

This is so scary!

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

Capitalized...Serve!