AFAIK, no one asks the perfection. However a translation is to translate an idea, from one tongue to another. This is not paste of words like a collection of 'spaghetti'. As I said GT is a robot, it is fine for some basic purpose, and in fact a good job of Google. However it does not suit for a complex text, and tongue, like it was posted. My purpose was to understand whether the WS-15 is ready or not. Is this engine still in test ? If yes, until when ? The J-20 will be equipped with this engine, so when ? I noticed that most of the time regarding chinese military news, it is always a matter of 'unknown' fans, if not 'fakes' on Internet went out of nowhere. No straightforward news of chinese's media mainstream networks. I don't know how to think.
You are asking for the impossible. Of the Chinese members in this forum, and their supporters,
NONE of them served in the military and/or have experience in related fields. As such, they cannot explain complex technical issues involved. In the past, some tried and they ended up butchering the technical ideas in explaining and moving so far out that they ended up defying the laws of nature in trying to hype up Chinese accomplishments.
At the theoretical level, a turbine, aka 'jet', engine, is the same as the internal combustion engine in your car. We have an enclosed chamber, air, fuel, a fuel atomizing method, an air-fuel mixture method, an ignition source, and finally a method to control and exploit the explosion.
To move a car, we direct the fuel-air explosion into mechanical actions. Pistons, connecting rods, crankshafts, transmission, and so on...
To move an aircraft, we direct the fuel-air explosion into atmosphere, and Newton's laws takes over, to simplify a bit.
So then why is it -- if at the theoretical level both ideas are the same -- the turbine engine is so difficult to design, engineer, operate, and maintain? If you look at both methods, it seems the turbine engine should be easier to do all those things. Theoretically, we are not translating the explosion into mechanical actions. We are simply venting to atmosphere.
The theory is actually correct. The turbine engine is
CONCEPTUALLY simpler precisely because we are not translating the force of the explosion into mechanical actions to the extent of the automobile version of the internal combustion engine.
In the auto version, we have mechanical translations in the up/down (pistons) and rotational (crankshaft).
In the turbine design, we have a rotating core shaft. And that is it.
The problem is
HEAT.
Heat in the internal combustion engine design for the car is
NOT constant. We have an explosion and then none for one chamber. Same for the other chambers. Now repeat for all chambers. It is called the 'firing order'.
https://en.wikipedia.org/wiki/Firing_order
Look at it another way...Heat and mechanical actions in the automobile version of the internal combustion engine comes in pulses. Because of this, and the lower temperature in the automobile version, materials in the auto version can be less 'exotic' which means easier to manufacture.
https://en.wikiversity.org/wiki/Internal_combustion_engines
Ignition of the fuel in the cylinders produces temperatures of 700°C or more.
https://cs.stanford.edu/people/eroberts/courses/ww2/projects/jet-airplanes/how.html
Inside the typical commercial jet engine, the fuel burns in the combustion chamber at up to 2000 degrees Celsius.
So when we combine constant heat sources with higher temperature, we can see that even though the turbine engine is conceptually easier, the turbine engine is much more difficult to engineer and manufacture due to the demands for more 'exotic' materials that can withstand the constant heat.
- Concept
- Design
- Engineering
- Operation
- Maintenance
The last three items -- regarding heat -- are literally killers of any plan for a combat type of turbine engine.
The MIG-25 and SR-71.
The MIG is famous for its ability to reach Mach 2 or even higher. But it is well known that once the engine was pushed to that performance level, it must be scrapped at mission end. Not rebuilt, but essentially sent back to the manufacturer for disposition, which always means scrap status.
The SR, on the other hand, just needs its engine oil sampled and if there are any maintenance issues involved, line maintenance can be done by high school graduates.
What this means is that we can have high performance at the cost of operation and maintenance, or operation and maintenance at the trade-off of high performance. The SR-71 got all three items -- performance, operation, and maintenance -- done. The MIG-25 does not. When I was active duty and stationed at RAF Upper Heyford, I have friends at RAF Mildenhall who were with Det 4 SR-71 operators. The SR-71 can attain speed of higher than Mach 3+. Everyone knew it then, and everyone knew it now. And the PW J58 engine does not need a rebuilt after each unofficial Mach 3+++ speed run.
Here is an excellent laymen level source to understanding the turbine engine, specifically on the difficulties of heat...
https://www.americanscientist.org/article/each-blade-a-single-crystal
The SR-71 is mentioned along with other military high performance combat aircrafts. The idea that each compressor blade is essentially a
SINGLE CONTINUOUS CRYSTAL is mind boggling, to say the least. But this is the problem for any country trying to match the performance level of what have been accomplished by US or by anyone else.
The core would be about 1/3 down the overall length of the entire engine. That means each blade would be 1/4 the height of the man. Now imagine a blade to be a
SINGLE CONTINUOUS CRYSTAL.
The J-20 can have the power necessary from its engines, but does the engine design itself have the durability and reliability necessary for the jet to have long term deployment? There were very few SR-71 and yet whenever the need for information, the jet always delivered. That is the level of overall performance the military want and need.
Finally...You will not see anything like what I posted above from the Chinese members here. Nothing I posted is 'classified' secret. There is not a single math equation. And yet, am willing to bet
YOUR understanding of the difficulties of designing a high performance turbine engine, civilian and military, just increased dramatically. From this point on, any claim about the WS-15 must be taken with doubts and hold against what you learned about the turbine engine from publicly available sources.