"The aircraft would be initially powered by two nine ton thrust class WS-13E engines (improved Chinese copies of RD-93), and to be later powered by 10-11 ton thrust WS-19 engines in the late 2020s (in a thrust class of F414 or EJ200). The use of interim engines for the carrierborne FC-31 variant will not be dissimilar from the J-20’s use of interim engines prior to receiving intended its WS-15s. However, there have been some indications that the WS-19’s
development cycle may be slightly shorter than the WS-15, as it may have benefited from cross applicable research and development originally conducted for the WS-15."
https://thediplomat.com/2019/09/beyond-chinas-j-20-stealth-fighter/
So Russia is not agreeing to provide us with RD33 engines as they want to sell whole aircrafts cause that is economically feasible. The lot China had for RD93 is also finished and Russia is also not providing china with more engines. We have already tested WS13 and didn't like the result. For future now we are left with WS19.Right now 5 units of WS19 are being produced annually and the capacity will be increased. So JF17 Block lll & J35 will have this engine .
WS19 Huangshan
If the FC-31 can get a suitable engine, its overall performance will be greatly improved. Judging from the current technical level and public information of China's aviation industry, the current FC-31 "Yingying" is not likely to have super-patrol capability at present. China's second fifth-generation aircraft FC-31 was initially rejected by the Air Force, and a large part of this decision was due to the engine.
Compared with the American F-35, which is also a carrier aircraft, the J-31 thrust with two WS19 turbofans is about 24 tons, while the F35 has only 21 tons thrust. The J-31 has an empty weight of only 14.5 tons and the F35 is as high as 15.7 tons. It is 1.2 tons higher. In terms of combat load, Chinese sources claim the J-31 will be better than the F-35 and will be able to perform more functions than the F-35.
If only equipped with RD-93, the J-31 would have a hard time achieving supersonic cruise, becoming an incomplete fifth-generation machine; equipped with turbofan 19, J31 with a higher thrust-to-weight ratio can easily achieve supersonic cruise. Before Chinese equipment with the J-20, China’s understanding of the gap between the fourth-generation machine and the fifth-generation machine was not very clear; after the J-20, the differences in various aspects began to stand out, and the navy and carrier aviation also demanded the fifth-generation aircraft.
The engine is the core of the fighter. Even if the other performance of the fighter is good, it is no good if there is no good engine. For example, the fifth-generation fighter J-20 is still equipped with the AL-31 engine imported from Russia. However, this engine still can not fully support the full performance of the J-20.
Since the 1950s, turbofan engines have been highly valued by the world's aviation powers. With the development of turbofan engine technology, the United Kingdom, the United States, the former Soviet Union and other countries have developed a high push-to-weight ratio and high performance. Four generations of fighters, and since the mid-1980s, the world's aviation powers have begun to develop a new generation of engines for the fifth generation of fighters. Under this circumstance, the gap between the development of China's aero-engines and developed countries is already very large, and it must be quickly caught up.
At the 2018 Zhuhai Air Show, the big vector engine is not only the one that is equipped on the J-10B, but also a quietly lying on the stand, proclaiming China's second stealth fighter – J-31 will soon have a domestic turubofan engine; this engine is the turbofan 19 Huangshan medium thrust engine that had only appeared in rumors in the past two years. For a double-engine medium-sized fighter, the thrust and fuel consumption of the large thrust engine are too large, wasteful money, and poor cost-effectiveness; the most efficient method is to install two medium-thrust engines, and the WS19 is such an engine. China Aviation Industry Corporation had previously disclosed a vector engine with a maximum thrust of 9800Kgf. This engine is considered by the outside world to be the WS-19 "Huangshan" engine matched with FC-31. This project has produced and successfully completed the development of QC185, QC400, GT25000G military ship-borne turbine shaft blades, WS18, WS19 turbofan engine shaft blade development, 624 AT project drones and other models to attack the mission. In mid-2017, China Aviation Industry Corporation first published an engine model called "Turbofan-19" (WS-19) for a summary of the results of the "Shaft-type blade universal combination tester". Some military observers revealed on the Internet that "TurboFan-19" is a long-rumored new Chinese engine. It is similar to the name of "Taihang" and "Emei", and the name of "TurboFan-19" is "Huangshan". The target of the turbofan-19 is the F414 turbofan engine, which is larger than the European EJ200 engine in terms of maximum thrust.
Before the turbofan-19 model was confirmed, the detailed report on China's new medium-thrust turbofan engine was only the "S3-2 type technical verification machine" project. The S3-2 type technical verification machine was a double rotor and afterburner. The turbofan engine with vector nozzle has a maximum state thrust of 9800kgf, and the thrust-to-weight ratio is 9th. The goal is to obtain the national project after the verification technology is up to standard, and become an important member of the domestic engine type spectrum. Aeroengine market demand for medium thrust turbofan engines with vector nozzles.
From the performance parameters of the S3-2 type technical verification machine and the performance description of the turbofan-19 "Huangshan" on the Internet, the two are very close. It is possible that the advanced technology development of the S3-2 type technical verification machine has reached the target. After obtaining the approval of the engine model development project, it entered the prototype development stage.
At some airshows in China a few years ago, there was an unidentified medium-thrust engine more than once. The maximum afterburning thrust was 9500kgf. In terms of appearance, this engine not only has a structure similar to the Russian RD93. There are also similarities with the European and American F404 and EJ200 engines. However, this engine appeared in the air show, there is no follow-up related information to prove that it uses the official model and name.
https://www.globalsecurity.org/military/world/china/ws19.htm