Chinese Engine Development

Hendrik_2000

Hendrik_2000

Lieutenant General
It was first observed tested in IL76 back in June 2014. So 8 years has gone by with many set back and disappointment along the way
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Recently, a photo of a large bypass ratio turbofan engine was exposed on a Chinese aerial test bed. This photo shows a new engine completely different from the Russian-made D-30 engine, which was installed on an aerial test bed. According to the test, the nacelle and structure of the engine are similar to the American CFM56-7 engine and GE90 engine.

According to foreign media reports, China has imported a batch of Il-76 transport aircraft from Russia, which were converted into a batch of unknown number of engine test platforms dedicated to testing new domestic engines. China's heavy-duty strategic transport aircraft Yun 20 has no suitable domestic engines for use, so the test flight of the Yun 20 is the same as the current Il-76, equipped with D-30 engines. The aircraft exposed this time is the Il-76 test platform. The engine mounted on the inside of the left wing of this aircraft has a short and thick shape, which is obviously different from the other three relatively slender D30. It is likely to be the WS-20 (turbofan 20). Dowby turbofan engine, and WS-20 is the "genuine" engine of Yun-20.

Russia does not export more advanced engines to China

The D-30 engine is not advanced. Compared with the new-generation engine, its duct is relatively small and the fuel consumption rate is high. Russia’s newly improved Il 476 transport aircraft has replaced the D-30 with a more advanced PS-90 engine. Russian media claimed that Russia has refused to export PS-90 engines to China. The D-30 is currently China's only usable turbofan engine with no afterburner bypass ratio. The US media called the localized model WS-18. Currently, China's three main combat models: Il-76, H6K "God of War", and Yun-20 are all equipped with D-30 series engines.
 
Deino

Deino

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By the way ... any idea what type of engine under the Il-76LL could be? It looks slimmer than the D30-KP-2 and as such could be an engine for a fighter-sized type? ... maybe the WS-13E, WS-19??? I have no idea.


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L

latenlazy

Brigadier
Deino said:
By the way ... any idea what type of engine under the Il-76LL could be? It looks slimmer than the D30-KP-2 and as such could be an engine for a fighter-sized type? ... maybe the WS-13E, WS-19??? I have no idea.


View attachment 70757
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A middle weight weight military turbofan should have an engine diameter of about half the D-30KP, and a heavy weight military turbofan should have a diameter about 2/3 the D-30KP. The only two heavy weight engines still in development that might be at flying test bed stage I can think of are the WS-15 and whatever WS-10 variant the H-20 might end up flying with.
 
G

gelgoog

Lieutenant General
Registered Member
Hendrik_2000 said:
...
Russia does not export more advanced engines to China
The D-30 engine is not advanced. Compared with the new-generation engine, its duct is relatively small and the fuel consumption rate is high. Russia’s newly improved Il 476 transport aircraft has replaced the D-30 with a more advanced PS-90 engine. Russian media claimed that Russia has refused to export PS-90 engines to China. The D-30 is currently China's only usable turbofan engine with no afterburner bypass ratio. The US media called the localized model WS-18. Currently, China's three main combat models: Il-76, H6K "God of War", and Yun-20 are all equipped with D-30 series engines.
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A lot of PS-90 engine versions cannot be exported easily. They use Western components.

The Russians have a limited production capacity for the PS-90. The D-30 engine is also a lot cheaper to produce. That is one reason why the Russians have been taking forever to manufacture the Il-76 with PS-90 engines.

Also the initial production of PD-14 engines for example was only 4 engines a year. Only recently did they open up a new modern test facility for PD-14.

1617995033095.png
An old picture with the WS-20 on an Il-76 test aircraft.
 
T

Tirdent

Junior Member
Registered Member
The only PS-90 version with any Western content whatsoever was the PS-90A2, which never entered production for precisely that reason. As did most planned variants actually, apart from the industrial gas turbine, all production models were minor derivatives of the base model. The PS-90A76 is simply identical hardware derated to 14.5tf, the PS-90A1 has a new HPT to cope (sort of - its average time on wing is markedly shorter!) with the higher TIT at the increased 18tf rating. That's basically it.

It's an interesting question why Russia never sold any PS-90s to China, considering that the engine has been exported quite a bit actually (India, Jordan, Azerbaijan, Cuba, North Korea*). My guess is that it's a combination of lack of opportunity (the failure of that 38 airframe Il-76/78 order in the 2000s) and then concern about competition from the Y-20 project that resulted. Because now that the latter has competitive engines, I doubt the new-built Il-76MD-90A (Il-476) will stand much of a chance on the export market, unless the Y-20 is unavailable.

As for the PD-14, none of its applications (MS-21, Il-276) has entered production yet.

* Exporting to North Korea an engine with too much Western content for Chinese sales? I think not ;)
 
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Godzilla

Godzilla

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Hendrik_2000 said:
Well I found this explanation

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In almost every large turbofan I see, the LP turbine stages outnumber the HP turbine stages by a factor of at least 2. Here's a photo of the RR Trent 900:
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The Trent 900 (like most Rolls-Royce turbofans) is a 3-spool turbofan, rather than a 2-spool. But even here, my observation holds. There are far more LP turbine stages than the middle or high pressure stages.
Why is this?

Because the LP turbine extracts power for the fan, which requires the most power. The HP and IP turbine only extract power for their connected compressors - the LP turbine extracts power for the fan and the LP compressor. The fan does work on all airflow through the engine, the compressors only on a fraction (10:1 for a high bypass like the Trent 1000). The fan produces up to 75% of the thrust of the engine.

From
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: the cross section of the Trent 1000. It shows that the LP, IP and HP rotors have different rotational speeds, but does not list them. Another (older) presentation lists them as 3600. 6800 and 10200 RPM. Rotational speed goes down as the volume of the mass stream goes up.

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An old textbook of mine gives the power P extracted from a turbine stage as:



P=m˙⋅u⋅vax⋅[tan(α2)+tan(α3)]P=m˙⋅u⋅vax⋅[tan(α2)+tan(α3)]


with

  • m˙m˙ = mass flow [kg/s]
  • u = tangential blade velocity [m/s]
  • vaxax = axial gas velocity [m/s]
  • α2α2 and α3α3 angles according to the figure below.
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So the tangential speed of the turbine blade is in the equation for power extraction, which is composed of rotational velocity and blade radius. The faster the turbine turns, the more power can be extracted per stage, and the fewer stages required. Why then does rotational velocity go down with pressure? (HP = 10,200; IP = 6,800).

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The reason is the constructional limits of the turbine. As the gas stream expands, the turbine blades become larger and are mounted at a greater axial distance, which results in greater centrifugal forces which are proportional to blade mass, rotational speed and distance from the axis. In order to limit centrifugal forces, the rotational velocity of the rotor is reduced: each subsequent stage turns at a lower RPM. Notice that a lower RPM can be compensated by mounting the blade further away from the rotational axis.

The LP rotor of an un-geared engine runs at the same rotational velocity as the fan. Its optimal RPM for the turbine may be higher, and that can be accommodated by the geared fan. As the bypass ratio gets higher, the LP turbine will be extracting a higher fraction of total power from the airstream - turboprops and turboshafts have a gearbox in between the LP shaft and the propeller/rotor, and the high bypass fan approaches the relative dimensions of a propeller...
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The LP compressor stages is directly related to the fan diameter/bypass ratio exactly per what you said. Trent 700 had a bypass ratio of 5, and it had 4 LP stages, Trent 1000 has a bypass ratio of 10, so it needs 6 LP stages.
Kind of funny that you used the Trent as an example. I think RR is replacing the trent with the ultrafan in the future, getting rid of the LP completely and going with the geared. Not sure if it still qualifies as a 3 spool engine though they still called the second stage IP. The trent 7000 has the gearbox though, and still the 6 stage IP. They are pushing the limits a bit too far though, as I heard the IP and HP blades are causing alot of problem on the newer trents. They should have gone for the lower hanging fruits like getting rid of the shrouds instead.. Are the Chinese engines shrouded or shroudless? (both for turbine stages and for the fan)
 
G

gelgoog

Lieutenant General
Registered Member
Tirdent said:
The only PS-90 version with any Western content whatsoever was the PS-90A2, which never entered production for precisely that reason. As did most planned variants actually, apart from the industrial gas turbine, all production models were minor derivatives of the base model. The PS-90A76 is simply identical hardware derated to 14.5tf, the PS-90A1 has a new HPT to cope (sort of - its average time on wing is markedly shorter!) with the higher TIT at the increased 18tf rating. That's basically it.

It's an interesting question why Russia never sold any PS-90s to China, considering that the engine has been exported quite a bit actually (India, Jordan, Azerbaijan, Cuba, North Korea*). My guess is that it's a combination of lack of opportunity (the failure of that 38 airframe Il-76/78 order in the 2000s) and then concern about competition from the Y-20 project that resulted. Because now that the latter has competitive engines, I doubt the new-built Il-76MD-90A (Il-476) will stand much of a chance on the export market, unless the Y-20 is unavailable.

As for the PD-14, none of its applications (MS-21, Il-276) has entered production yet.

* Exporting to North Korea an engine with too much Western content for Chinese sales? I think not ;)
Click to expand...

From what I understand they only manufactured the PS-90A2 or similar to power the Tu-204SM prototype. Those exports, I think, use the original PS-90 or A1. But like I said the production rate was never that high to begin with. For example the maximum production rate per year of the Il-96 was 3 aircraft in 1994. That is a quad-engine. The maximum production rate of the Tu-204 was 10 aircraft in 2008. That is a dual-engine. Unlike civilian airliners a military transport isn't continuously operating. Plus Russia has its own oil. So fuel consumption is a minor concern and engine cost is a lot more important.
 
BoraTas

BoraTas

Captain
Registered Member
Godzilla said:
The LP compressor stages is directly related to the fan diameter/bypass ratio exactly per what you said. Trent 700 had a bypass ratio of 5, and it had 4 LP stages, Trent 1000 has a bypass ratio of 10, so it needs 6 LP stages.
Kind of funny that you used the Trent as an example. I think RR is replacing the trent with the ultrafan in the future, getting rid of the LP completely and going with the geared. Not sure if it still qualifies as a 3 spool engine though they still called the second stage IP. The trent 7000 has the gearbox though, and still the 6 stage IP. They are pushing the limits a bit too far though, as I heard the IP and HP blades are causing alot of problem on the newer trents. They should have gone for the lower hanging fruits like getting rid of the shrouds instead.. Are the Chinese engines shrouded or shroudless? (both for turbine stages and for the fan)
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Ultrafan is an extremely ambitious project. Its projected specs are:
3 shafts
15:1 BPR
70:1 compression ratio
High TIT (2000 C ?)
Reduction gear
Variable-pitch fan
composite fan and fan case
Advanced titanium alloy blisk low-pressure compressors (LPC)
Heavy use of intermetallics in HPC, LPT and the nozzle
CMC in HPT/IPT stators and combustion chamber liner
Twin-annular, pre-swirling lean-burn combustor
Heavy use of 3d printing

It is almost like they are attempting to regain their position against GE and P&W. They are targeting a breakthrough in all parts. They will probably run out of money while doing this. Maybe China can help with that one:D
 
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