TR Propulsion Systems

[Yasar_TR]

This tech combined with other complementary technologies like coatings a cooling features will probably already get us to 1580+°C TIT level.

Source for this figure?

 

[Zafer]

Source for this figure?

This is my guess based on the performance levels of some modern day engines shown in the table below. I would expect a threshold level be passed with the TF35k engine.

 

[Strong AI]

1500 - 1800 Kelvin

 

[Zafer]

Alloys' performance stops improving at around 1400 °C and additional performance is achieved mostly through cooling. Small blades offer little real estate to implement cooling and larger blades can host more cooling features hence deliver better peak performance. Also 5 years passed since the time of this implementation, we can expect improvements.

 

[Zafer]

Snecma M88 achieves 1577 °C with air cooled, ceramic coated, single crystal turbine blades made from a new AM1 alloy (N-18 alloy in the final production engines),

So it is reasonable to consider matching this performance level for the TF35k engine.

Snecma M88 - Wikipedia

en.wikipedia.org

Shenyang WS-15 - Wikipedia

en.wikipedia.org

 

[Zafer]

TS1400 helicopter engine uses the first generation of TEI single crystal blade technology and TF35000 engine will use the TEI third generation single crystal technology.

Birinci nesil kristal ile TS1400’e uyguladık, 3. Nesil ile TF35000’de uğraşıyoruz, 4 ve 5’inci nesil için çalışıyoruz.

https://twitter.com/i/web/status/2047959577677771010

 

[Yasar_TR]

Single crystal turbine blades have brought the capability of having higher tolerances with which to work when designing turbofan jet engines.

Directionally Solidified turbine blades were the start of this process.

When molten metal is allowed to cool slowly it forms crystals.

If you pull a molten material along its longitudinal molecular axis you create directionally stable crystalline structures. They lose their pliability. But become much harder and difficult to snap under load.

By using this cooling method and directionally solidifying Nickel Super Alloys, layers upon layers of crystallised material is obtained. Blades made by this method when under extreme heat and strain, will see their layers start moving over each other giving boundary grain problems and failures in the end.
To overcome this problem the directionally solidified blades are cast as single crystals by controlling heat extraction in a vacuum.

By adding different exotic rare earth elements to the mix you achieve a newer and more durable generation of single crystal blade.
Although each generation of blade imparts an increase of TIT of around 30 to 50 degrees Celsius, together with the accompanying ceramic treatment the overall additional heat durability advantage could be as much as 100 to 150 Celsius.

Apart from imparting a heat advantage, newer generation blades’ creep degradation resistance is increased too. This gives a longer life to the engine in question.
But going beyond 3rd generation in these blades become economically unviable.

 

[Zafer]

But going beyond 3rd generation in these blades become economically unviable.

Source, apparently TEI team does not care about this.

 

[Yasar_TR]

Source, apparently TEI team does not care about this.

Nothing to do with not caring about it. From a technical achievement point they will try to obtain the technology whatever the cost. They decided to use 1st generation single crystal blades on TF6000, even though they had access to 3rd gen blades. Because that achieved the right results.

GE and P&W in 2004 developed 4th generation crystal blades and GE used it in f110 engines. But in mass production it is a different story. The F110-GE-129 and F110-GE-132 models widely utilize second-generation single-crystal superalloys, such as René N5 and PWA 1484

The GE F414 engine predominantly utilizes second generation single-crystal nickel superalloy turbine blades in its high-pressure turbine.

IHI used 5th generation crystal blades in their XF9 5th generation jet engine. They too would be inclined to use no more than 3rd gen in mass production unless the user insists and is prepared to pay the premium.

Almost all commercial engine manufacturers use 2nd gen single crystal blades in hp sections.

 

[IC3M@N FX]

Correct me if I'm wrong...

The 3rd+ generation (TEI TF 35000) must contain at least 6% rhenium for 1580–1650 °C

The 4th generation must contain high levels of both rhenium and ruthenium for 1650–1750 °C

 

[Yasar_TR]

Correct me if I'm wrong...

The 3rd+ generation (TEI TF 35000) must contain at least 6% rhenium for 1580–1650 °C

The 4th generation must contain high levels of both rhenium and ruthenium for 1650–1750 °C

These are arbitrary numbers. It all depends on how well your cooling processes are applied and how good your ceramic coating is. Russian AL41 class engines use Directionally Solidified blades (NOT single crystal) but achieve a TIT of 1645+ degrees Celsius. Even as high as 1700 degrees Celsius is quoted. To achieve nearly 20000lbf dry 35000 wet thrust.

 

[Zafer]

Users want to maintain technological edge over the competition, if it makes sense for them they will bear the cost and ante up the money. Countries that can source the raw materials that go into making of the high end alloys domestically can use them to be on top of the game. The cost is only a matter for the foreign buyer while domestic users pay only a fraction comparatively. It is natural to have science going a few generations ahead while the industry only employs what is achieved acceptably well. Going above and beyond what is acceptable is only a matter of priorities and resource allocation once you have the technology of making it.

What is too costly today maybe mainstreram tomorrow. So TEI should definitely pursue pushing its capabilities to further levels in this branch of blade making.

 

[uçuyorum]

These are arbitrary numbers. It all depends on how well your cooling processes are applied and how good your ceramic coating is. Russian AL41 class engines use Directionally Solidified blades (NOT single crystal) but achieve a TIT of 1645+ degrees Celsius. Even as high as 1700 degrees Celsius is quoted. To achieve nearly 20000lbf dry 35000 wet thrust.

But for how long

 

[Yasar_TR]

But for how long

That is why we and most Western engine manufacturers use single crystal turbine blades. They last longer. Because the creep degradation sets in much slower.

But the high inlet temperature is not only specific to engines employing single crystal blades. Yet It is easier to attain higher TIT values with single crystals. But just with single crystal blades the engine parts would still melt if not cooled and ceramic coating applied. Better crystals means higher top temperature threshold with cooling and coating. So they are interdependent on each other in a way.

 

[Nilgiri]

That is why we and most Western engine manufacturers use single crystal turbine blades. They last longer. Because the creep degradation sets in much slower.

But the high inlet temperature is not only specific to engines employing single crystal blades. Yet It is easier to attain higher TIT values with single crystals. But just with single crystal blades the engine parts would still melt if not cooled and ceramic coating applied. Better crystals means higher top temperature threshold with cooling and coating. So they are interdependent on each other in a way.

It really boils down to the normal distribution vis a vis the factor(s) you are changing.

Old post i plot the normal distribution conceptually: https://defencehub.live/threads/propulsion-systems.3/page-57#post-111270

So if you keep some relevant TIT the same between:

- S(X) (newest/best),
- DS(X) (intermediate)
- Non-DS(X) (oldest/worst)

and then apply exact same cooling mitigations, manufacturing quality, design etc.... i.e hold everything else ceterus paribus in this multivariate situation and only play with grain boundary prevalence (where S(X) achieves as "n=0", DS(X) as "small n" and non-DS(X) as "high n")

...you will get three different normal distributions on their failures commensurate to their grain boundary prevalence (and thus problem initiation + growth rate, all of which contribute to the normal distribution position w.r.t time).

Similarly if you keep S(X) the same alongside cooling....you can now use TIT as the factor to change (to increase it, take a hit on the normal distribution spread and see where the tradeoff is now optimal w.r.t some red line you have for the X% failure rate you set).

i.e for each failure rate, the TIT (required to cause it with same amount of time seen) will be higher for S(X) relative to DS(X) etc.

 

[Bogeyman]

Single crystal wing types and generational differences

https://www.metalurji.org.tr/dergi/dergi169/d169_3039.pdf

@TheInsider @Yasar

Here are some illustrative images related to single-crystal turbines.