Photographic comparison of engines on J-15 Flying Shark and J-11
But these are still AL-31F !
"Some components onboard the J-15 Flying Shark are based on those onboard J-11B, such as the anti-ship enhanced PD radar, the glass cockpit as well as the
improved WS-10 turbofan engine." (Source: Chinese Military Aviation)
J-11 with WS-10 engines
There are three reasons that the J-15 Flying Shark is equipped with "improved WS-10 turbofan engines."
1. Every publication (e.g. Chinese Military Aviation, Defense Update, etc.) claims the J-15 Flying Shark is using WS-10 engines.
2. J-11s equipped with WS-10 engines are old news. Since J-11s have been flying with WS-10 engines, it is reasonable and logical to install WS-10 engines on navalized J-11s.
3. If the J-15 Flying Shark was equipped with AL-31 engines, the Russian press would be crowing about it to the world.