Chinese Engine Development
- Thread starter jackbh
- Start date
by78
General
I think this press blurb refers to the engine for L-15. Sharing it here for the record.
Don’t think so. From the sounds of it this is just the gearbox for the engine.
by78
General
Ok, thanks.
Well, it's a bit curious... 20MW is way too much for a conventional accessory gear box (well below 1MW typically), but at the same time it is also nowhere near enough for a CJ-2000 class gear driven fan. For a CJ-1000 class engine at ~140kN it would be *almost* good enough (more like 23 to 25MW), but for reference, UltraFan requires a shaft power of some 70MW for up to 440kN. Even if we scale that down some for a thrust of ~350kN, 20MW is clearly far off the required power level (UltraFan has been tested up to 64MW, AFAIK).
The Russian NK-93 prop fan at 180kN had a 36MW gearbox IIRC (but with its ultra-high BPR the shaft power requirement would've been greater than a conventional engine of the same thrust).
Perhaps a sub-scale proof-of-concept test??? If so, they clearly have a ways to go, though.
The Russian NK-93 prop fan at 180kN had a 36MW gearbox IIRC (but with its ultra-high BPR the shaft power requirement would've been greater than a conventional engine of the same thrust).
Perhaps a sub-scale proof-of-concept test??? If so, they clearly have a ways to go, though.
So after doing a bit of perusing of the term in Chinese I think I have to take back what I said. The term seems to show up exclusively in reference to geared fan engines.
This is especially fascinating as I've been wondering for some time whether the Russian counterpart to the CJ-2000, the PD-35 might not turn out to be a GTF. It has, to my knowledge, never been stated to be one, but ever since the first specs were released, I was thrown off by the large 3.10m fan diameter. That's almost a foot larger than the GEnx and Trent 1000 and still 10cm bigger than the more powerful Trent 900, GP7200 and Trent XWB.
All these engines hover round the 9.0 to 10.0 BPR mark, so clearly UEC is shooting for more than that - but above 11.0 really necessitates a geared fan in practice. Fan tip speed, if coupled directly to LPT rpm, otherwise gets too high for noise requirements and the number of LPT stages grows so large that a gearbox with a small, high-speed LPT wins the weight race. But a 9% increase in fan size is worth more than 10% in BPR - that's about the same difference as the diameters of the PD-14 (BPR 8.5) and PW1400G (BPR 12+)! BPR is roughly related to area of course, so roughly proportional to the square of linear dimension.
Then, recently, photos of this PD-35 model were released, and it has a number of curious features about it:
The nozzle and plug are conspicuously small in diameter (indicating a high-speed LPT de-coupled from the fan?) and there is this large circumferential gap forward of the LPT casing. Cooling air outlet for power gearbox heat rejection? Very intriguing developments with both engines for the CR929 here, in any case!
All these engines hover round the 9.0 to 10.0 BPR mark, so clearly UEC is shooting for more than that - but above 11.0 really necessitates a geared fan in practice. Fan tip speed, if coupled directly to LPT rpm, otherwise gets too high for noise requirements and the number of LPT stages grows so large that a gearbox with a small, high-speed LPT wins the weight race. But a 9% increase in fan size is worth more than 10% in BPR - that's about the same difference as the diameters of the PD-14 (BPR 8.5) and PW1400G (BPR 12+)! BPR is roughly related to area of course, so roughly proportional to the square of linear dimension.
Then, recently, photos of this PD-35 model were released, and it has a number of curious features about it:
The nozzle and plug are conspicuously small in diameter (indicating a high-speed LPT de-coupled from the fan?) and there is this large circumferential gap forward of the LPT casing. Cooling air outlet for power gearbox heat rejection? Very intriguing developments with both engines for the CR929 here, in any case!
by78
General
I couldn't find a downloadable link, but here is one that you can read online. Please give a summary if you find anything revealing.