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I feel like if the issue is using research as a proxy of broader development, then if the coating and cooling research is fairly advanced, that should indicate the rest of the development is fairly advanced, no?
Chinese Engine Development
- Thread starter jackbh
- Start date
Yup.
And to the point above, there’s also pretty visible research output on carbon fiber as well as ceramic fan blades.
I would make the case here that increasing general literacy on how these engines work and what technology goes into them will make it much easier for us to parse and identify relevant information about China’s own engine projects. There may be developments we miss simply due to the fact that progress in component technologies are overlooked or misunderstood. Before you go looking you have to know what to look for, and not every substantive piece of information is going to have “major Chinese engine project” headlining it.
Not really. Aerodynamics? Decelerating diffusor flow (compressors/fans) vs. accelerating nozzle flow (turbines), with all the attendant consequences for the viscous boundary layer. That's in essence why large engines (too much mass flow to use high-PR centrifugal compressors) generally have far more compressor stages than turbine stages, BTW. Add the cooling air jets emanating from the turbine blades and interacting with the exhaust gas flow and it's a very different problem set.
Materials? In addition to the temperature/strength interplay that has been mentioned already, there's also high temperature corrosion (chemical oxidation) to consider. This is why even stationary nozzle guide vanes (which are not subject to the high centrifugal loads seen in the rotor blading which result in creep issues) are typically single crystal. It improves resistance to chemical attack, in addition to the better mechanical properties.
Carbon fiber fan blades, but surely ceramic *turbine* blades? Ceramics have good temperature tolerance and chemical corrosion resistance, but impact strength is unsuitable for a fan.
Remember, my point was that there is a clear indication about where the *general* direction of research has been. It’s very unlikely that they’d be looking into coatings for fan blades and be completely oblivious to similar applications for other parts of the engine. I could dig around for research specifically on turbine blade materials but I only noticed the research on coating for fan blades because I was mostly interested in exploring where China was on compressors.
Wrt to ceramic blades (which I think is still mostly focused on compressors) China isn’t the only country looking into this. I have a friend in the US who worked on research on ceramics for use in engine blades when he was still in academia. If you asked me CMCs are obviously much more feasible than pure ceramics, *but* the point is that this sort of research is being done in China.
Great image - including a gif - showing the new WS-10B (?) featuring the slightly longer modified nozzle feathers. In comparison to a regular / older WS-10A an a J-11BS.
(Image via CCTV and @沉默的山羊 from Weibo)
Here is the gif:
(Image via CCTV and @沉默的山羊 from Weibo)
Here is the gif:
Those are installed on the J-16.