Kaveri & Aero-Engine: News & Discussion

SaiK · Post by **SaiK** » 17 Feb 2011 11:31

^good question, if it so, then it has to be the eco core.

Kanson · Post by **Kanson** » 17 Feb 2011 11:51

Snecma M88-3 Eco Turbine inlet temperature is published as around 1800 deg but in the Kaveri schematic diagram turbine inlet temperature is mentioned as 2200 deg.

geeth · Post by **geeth** » 17 Feb 2011 12:07

^^Also, the pressure drop across tubines appears to be too much..not sure whether this is the case with modern engines, as the compressor would suck up a lot of energy to a big increase the pressure rise across it.

Singha · Post by **Singha** » 17 Feb 2011 12:08

apart from less SFC, does a turbofan perform better at lower altitude vs turbojets? thats the kind of altitude our cruise missiles would adopt. and the SFC gap might only increase as our design matures and is tested.

Indranil · Post by **Indranil** » 17 Feb 2011 12:22

Thank you Kanson-ji

geeth · Post by **geeth** » 17 Feb 2011 12:29

>>>Snecma M88-3 Eco Turbine inlet temperature is published as around 1800 deg but in the Kaveri schematic diagram turbine inlet temperature is mentioned as 2200 deg.

One possibility is that 2200 is the temperature inside the combuster, which is then cooled using tertiary air to bring it down to a more manageable level, before entering the turbine blades

Kanson · Post by **Kanson** » 17 Feb 2011 14:12

geeth wrote:>>>Snecma M88-3 Eco Turbine inlet temperature is published as around 1800 deg but in the Kaveri schematic diagram turbine inlet temperature is mentioned as 2200 deg.

One possibility is that 2200 is the temperature inside the combuster, which is then cooled using tertiary air to bring it down to a more manageable level, before entering the turbine blades

I don't think so. And not heard such thing.

At 2200 deg and with stated pressure ratio we are truly looking at thrust greater than 120 KN and depending upon the flow rate it could be greater than 130 KN. It very much augurs with the disposition of getting the highest rated GE F414 engine for the LCA which will be somewhere around 120 KN. But we may flat rate it at 100 KN, who knows.

geeth · Post by **geeth** » 17 Feb 2011 15:20

I don't think so. And not heard such thing.

2.3 The casing and the liner

After the airflow has passed the diuser, it is split up by the liner. One part of the airflow goes through the region between the liner and the casing. This region is called the annulus. Another part of the airflow enters the mixing chamber, where fuel is injected.
There are several reasons for splitting up the flow. First, the air-to-fuel should have the right value. If it is too high, the mixture will not ignite. Also, the velocity of the flow leaving the diuser is still too high.The part of the flow that will be ignited has to be slowed down even further.

The liner is divided into three sections. There is a primary zone (PZ), a secondary/intermediate
zone (SZ/IZ) and a tertiary/dilution zone (TZ/DZ). The main function of the PZ is to provide enough time for the fuel to mix and combust. The goal of the SZ is to provide enough time to achieve full combustion. This significantly reduces bad reaction products like carbon monoxide CO and unburned hydrocarbons (UHC). Finally, the goal of the DZ is to reduce the temperature of the outlet stream, such that it is acceptable for the turbine.

http://www.aerostudents.com/files/gasTu ... hamber.pdf

Kanson · Post by **Kanson** » 17 Feb 2011 15:29

^ Sir, you see such things for engines with FADEC ? and to drop temp from 2200 to 1800 ?

geeth · Post by **geeth** » 17 Feb 2011 15:43

^ Sir, you see such things for engines with FADEC ?

Honestly, I can't make out the connection between FADEC & tertiary cooling.. How do you cool the hot gas from combustion chamber to match the TET?

Austin · Post by **Austin** » 17 Feb 2011 15:57

Do we have any information on the Thrust Rating of GE-414S6 engine for Tejas Mk2 ?

vic · Post by **vic** » 17 Feb 2011 17:17

Kanson wrote:
geeth wrote:>>>Snecma M88-3 Eco Turbine inlet temperature is published as around 1800 deg but in the Kaveri schematic diagram turbine inlet temperature is mentioned as 2200 deg.

One possibility is that 2200 is the temperature inside the combuster, which is then cooled using tertiary air to bring it down to a more manageable level, before entering the turbine blades
I don't think so. And not heard such thing.

At 2200 deg and with stated pressure ratio we are truly looking at thrust greater than 120 KN and depending upon the flow rate it could be greater than 130 KN. It very much augurs with the disposition of getting the highest rated GE F414 engine for the LCA which will be somewhere around 120 KN. But we may flat rate it at 100 KN, who knows.

Aape mouth mein ghee shakkar or rum/whisky depending on your taste

SaiK · Post by **SaiK** » 17 Feb 2011 18:38

The only thing now that can choke is the inlet then... or perhaps politics.

cool.

Kanson · Post by **Kanson** » 17 Feb 2011 19:35

geeth wrote:^ Sir, you see such things for engines with FADEC ?

Honestly, I can't make out the connection between FADEC & tertiary cooling.. How do you cool the hot gas from combustion chamber to match the TET?

I guess, i'm not replying you properly. Usual way of representation is TET(inlet temp) which is important for the calculation. What i do in combustion chamber and what temp i reaches there is of little importance to exhibit my engine performance. In a general presentation, the temp that is talked about is turbine inlet temp aka combustion chamber outlet temp and not core temp of combustion chamber(as the one you are suggesting as 2200 deg). So this 2200 deg temp represents turbine inlet temperature and not core temp of combustion chamber.

One of the function of secondary air in combustion chamber is to cool the gas/air before the entry into turbine section if its exceeds the TET. FADEC controls the combustion process so effectively that it reduces unwanted fuel consumption and so the excess heat. So we normally hear with FADEC engines, we save fuel and get more power.

maitya · Post by **maitya** » 17 Feb 2011 21:47

Kanson wrote:
geeth wrote:^ Sir, you see such things for engines with FADEC ?

Honestly, I can't make out the connection between FADEC & tertiary cooling.. How do you cool the hot gas from combustion chamber to match the TET?
...
So this 2200 deg temp represents turbine inlet temperature and not core temp of combustion chamber.
...

Although I agree with what you say about TiT being the determining factor for a gas turbine engine performance, 2200deg temp can't be the TiT and is most probably the temperature attained in the combustor.

Besides the diagram in question, puts the unit as centigrade - and no turbine blade exists (yet) which can handle that high temperature (except maybe the ceramic ones, but then there are no military turbine engines that uses ceramic blades).

The highest TiT that I've heard of are for F119, which is what, IIRC, around 1550deg centigrade (~1823K).

Also 2200deg centigrade is very close to the stoichiometric temperature of "perfect" air-fuel mixture - which is what you'd expect if the combustor is designed and worked "perfectly", ensuring "non-smoky" engine etc.
If that kind of gas is allowed to flow to the turbine inlet without any cooling, it will simply melt. That is the reason about 2/3 of the compressor-generated "cold air" is bypassed the combustor and allowed to mix with this hot gas to bring it down the appropriate temperature that the materials of the turbine blades can handle.

SaiK · Post by **SaiK** » 17 Feb 2011 22:01

Saw a natgeo presentation of how rolls royce makes their sc blades, and how they mftr tiny holes in the direction of the air flow in the blade, through which air passes cooling the blades down at high temp. They said it was significant enough to consider air flow through these miniature holes in the blade to bring the temp down to about 20%? or so. Would that be thought off as well for k blades?

btw, can't we have the CMC material for the blades then? self healing!

geeth · Post by **geeth** » 17 Feb 2011 22:09

I guess, i'm not replying you properly. Usual way of representation is TET(inlet temp) which is important for the calculation. What i do in combustion chamber and what temp i reaches there is of little importance to exhibit my engine performance. In a general presentation, the temp that is talked about is turbine inlet temp aka combustion chamber outlet temp and not core temp of combustion chamber(as the one you are suggesting as 2200 deg). So this 2200 deg temp represents turbine inlet temperature and not core temp of combustion chamber.

I had a second look at the schematic diagram and now I feel what I said before is correct. Please look at the graph shown above the cut-away view of the engine. 2200 is shown at the middle of the combustion chamber (at which point the tempeture is max). From there on, the gradient of the graph is negative till it reaches 800. At the point where the hot gas enters turbine, the temperature is between 2200 and 800. So, TET has to be below 2200.

One of the function of secondary air in combustion chamber is to cool the gas/air before the entry into turbine section if its exceeds the TET. FADEC controls the combustion process so effectively that it reduces unwanted fuel consumption and so the excess heat. So we normally hear with FADEC engines, we save fuel and get more power.

Fadec will do only fuel metering and hance improve SFC (Like the electronic ignition in a petrol engine). It cannot directly control the combustion process. Unwanted fuel consumption means unburnt fuel, and unburnt fuel will tend to decrease the temp of hot gas. Therefore it helps the combustion process indirectly, by sending the optimum amount of fuel, thereby reducing the wastage. For efficient combustion, the combustion chamber has to be designed efficiently. The temperature in the combustiion chamber is max when the fuel is completely burnt. This hot gas temp is reduced by mixing it with optimum amount of cooler air in tertiary zone. These things are the basis for any engine design and is decided at the preliminary design stage itself (with or without FADEC).

Kanson · Post by **Kanson** » 17 Feb 2011 22:56

maitya wrote: Although I agree with what you say about TiT being the determining factor for a gas turbine engine performance, 2200deg temp can't be the TiT and is most probably the temperature attained in the combustor.

Besides the diagram in question, puts the unit as centigrade - and no turbine blade exists (yet) which can handle that high temperature (except maybe the ceramic ones, but then there are no military turbine engines that uses ceramic blades).

GE uses CMC for its F136 turbine rotor section and plans to use in GE F414 engine LPT section.

The highest TiT that I've heard of are for F119, which is what, IIRC, around 1550deg centigrade (~1823K).

Neither GE nor P&W publish their TiT. Hope you based your belief upon authentic material.

Kanson · Post by **Kanson** » 17 Feb 2011 23:06

geeth wrote:
I guess, i'm not replying you properly. Usual way of representation is TET(inlet temp) which is important for the calculation. What i do in combustion chamber and what temp i reaches there is of little importance to exhibit my engine performance. In a general presentation, the temp that is talked about is turbine inlet temp aka combustion chamber outlet temp and not core temp of combustion chamber(as the one you are suggesting as 2200 deg). So this 2200 deg temp represents turbine inlet temperature and not core temp of combustion chamber.
I had a second look at the schematic diagram and now I feel what I said before is correct. Please look at the graph shown above the cut-away view of the engine. 2200 is shown at the middle of the combustion chamber (at which point the tempeture is max). From there on, the gradient of the graph is negative till it reaches 800. At the point where the hot gas enters turbine, the temperature is between 2200 and 800. So, TET has to be below 2200.

I already guessed from where you are basing your arguments.

You can take it as you see fit. But a better argument would be that temp are misquoted in Celsius, instead it should be in Kelvin.

maitya · Post by **maitya** » 18 Feb 2011 00:50

Kanson wrote:
maitya wrote:
...
Besides the diagram in question, puts the unit as centigrade - and no turbine blade exists (yet) which can handle that high temperature (except maybe the ceramic ones, but then there are no military turbine engines that uses ceramic blades).
GE uses CMC for its F136 turbine rotor section and plans to use in GE F414 engine LPT section.

You are alluding to these links, I guess
General Electric primes CMC for turbine blades
New GE Engine Has Potential For Commercial Use

Gurneesh · Post by **Gurneesh** » 18 Feb 2011 01:06

Kanson wrote:
geeth wrote: I had a second look at the schematic diagram and now I feel what I said before is correct. Please look at the graph shown above the cut-away view of the engine. 2200 is shown at the middle of the combustion chamber (at which point the temperature is max). From there on, the gradient of the graph is negative till it reaches 800. At the point where the hot gas enters turbine, the temperature is between 2200 and 800. So, TET has to be below 2200.
I already guessed from where you are basing your arguments. You can take it as you see fit. But a better argument would be that temp are misquoted in Celsius, instead it should be in Kelvin.

In a gas turbine, the flame is kept as far from the blades as possible. 2200 Celsius must be the temperature of the flame front. After this the gases will cool a bit before entering the turbine.

This can be clearly seen by the pressure curve. The combustor starts at 620 cels. and continues till the pressure is constant.
As the hot gases enter the turbine, their pressure will drop significantly. So the turbine inlet is at a temperature lower than 2200 cels.

Plus kerosene has adiabatic flame temperature of around 2350 K @ 1atm. So the temperature might very well be in Celsius. Moreover, if the temperatures were in Kelvin then the compressor inlet would be negative celsius

Kanson · Post by **Kanson** » 18 Feb 2011 09:36

Kanson · Post by **Kanson** » 19 Feb 2011 06:22

http://www.geae.com/engines/commercial/ ... ustor.html

GEnx TAPS Combustor--The Most Advanced Combustor in the Industry

With our innovative single-annular TAPS combustor, the GEnx is designed to be the cleanest-burning engine in its class. This combustor will far and away comply with all existing and expected regulations for NOx emissions -- positioning GEnx operators for clean compliance for many years to come.

Cleaner combustion requires technology that delivers high efficiency and lower, more uniform flame temperatures. This is achieved with our innovative pre-mixing concept. By directing nearly all of the airflow through unique swirlers and around nested fuel nozzles, we create ideal pre-mixed fuel/air environment. And because NOx production is strongly driven by combustion temperature, these emissions will be drastically reduced.

Additionally, because all of the combustion air enters through the dome and mixers, no dilution holes are required on the new liner. This in turn reduces distress, leading to longer liner life and reduced maintenance costs.

The lower and more uniform temperatures produced by this combustor have another benefit, as well. They significantly improve the lives of all downstream components.

This clean, easy-to-maintain combustor is one of the many innovations that will give GEnx customrs advantages unavailable to anyone else. Just image how we've improved the other parts of this amazing new engine.

SaiK · Post by **SaiK** » 20 Feb 2011 03:26

http://books.google.com/books?id=AXtqMu ... ne&f=false

So, it ain't from Snecma at all! CMC/PMC - PMR-15 class materials for nozzle and other parts.

Ref: Page 409/6. Futuristic program.

And, all the more reason to cancel the $2b waste on Snecma partnership.

Kanson · Post by **Kanson** » 20 Feb 2011 18:46

Some kind gentleman has uploaded the specs of M88-4E from AI 2011 http://aeroindia2011pics.blogspot.com/

Even for M88-4E, published TIT is 1577°C, same as M88-2 and thrust is the same 75 KN. How much more the core is going to entertain for the Snecma-kaveri for the raise to the advertised thrust of 95 KN?

Though not comparable on one to one basis, there is raise of 66°C in TIT for F414-EDE from the F414-400 to get 15% more thrust at the cost of 2% raise in SFC.

SaiK · Post by **SaiK** » 20 Feb 2011 19:05

Even if they raise it to 95kN, it would fall short of 414 IN specs of 105kN. So, it is a failure from the start. Must stop this Snecma deal.

Drishyaman · Post by **Drishyaman** » 20 Feb 2011 19:21

Kanson wrote: Somehow this pic tells me, we already started adopting Snecma technology or getting guidance from Snecma in designing & maturing our Kaveri engine.

Kanson ji, Is this assumption of yours wrong then, with the above last post of yours showing that M88 4E will have have a thrust of 75 kN? Sorry !! but you left me confused.

Kanson · Post by **Kanson** » 20 Feb 2011 19:42

Drishyaman wrote:
Kanson wrote: Somehow this pic tells me, we already started adopting Snecma technology or getting guidance from Snecma in designing & maturing our Kaveri engine.
Kanson ji, Is this assumption of yours wrong then, with the above last post of yours showing that M88 4E will have have a thrust of 75 kN? Sorry !! but you left me confused.

As you probably know, M88-4E is the final iteration engine pack for Rafale. Dassault/Rafale seems to be happy with 75 KN engine. Improvements from M88-2 to M88-4E is advertised as reduction in TCO(Total cost of ownership). IOW, it extends the engine life and of less maintenance by using better material in the core which can either extend the engine life if it operates in lower temp to give 75KN or it gives nominal life at higher thrust with higher operating temp. Some happy "outspoken" Snecma official blurted out that their M88-Eco core can operate[TIT] at more than 1800°C and there were some news that M88-Eco went around 90-95 KN.

From M88-2 came M88-Eco and then came M88-4E.

Kanson · Post by **Kanson** » 21 Feb 2011 11:08

SaiK wrote:Even if they raise it to 95kN, it would fall short of 414 IN specs of 105kN. So, it is a failure from the start. Must stop this Snecma deal.

Not only you, there are people in official level thinks that Kaveri can pull itself on its own. As the timeframe of realizing this becomes important, if we can, i think, there is nothing wrong in taking help from whoever. I too think Snecma-Kaveri engine is going to be only an intermediate gap filler.

SaiK · Post by **SaiK** » 21 Feb 2011 21:06

my question to you Kanson, is this: Why do we need this gap filler? We have the Ge414 ToT to keep everything going per schedule.

srai · Post by **srai** » 22 Feb 2011 12:37

SaiK wrote:my question to you Kanson, is this: Why do we need this gap filler? We have the Ge414 ToT to keep everything going per schedule.

One is a Kaveri Hybrid (with a lot of Indian designed sub-components) , while the other is 100% foreign engine. Over time, bit-by-bit, it would be possible to indigenize the Kaveri's ECO core module. The same thing can't be said about the F414. You have to start using the Kaveri - the earlier the better ... otherwise it will be relegated to tech demo ... as you have pointed out when a 100% foreign engine is available, why use the Kaveri at all. Indigenization happens over time and even small success leads to something greater down the road.

chackojoseph · Post by **chackojoseph** » 24 Feb 2011 13:23

Ten fold increase in cost of Kaveri engine programme : Antony

SriSri · Post by **SriSri** » 24 Feb 2011 14:21

Cross posting from the Military Partnerships thread..
Kaveri Engine Production Negotiation With Snecma in Final Stage says Defence Minister

Hiten · Post by **Hiten** » 27 Feb 2011 18:18

dont't miss the header from page 2 onwards

http://www.scribd.com/doc/49632737/Indi ... ganisation

SaiK · Post by **SaiK** » 27 Feb 2011 18:54

srai, point of question is why with Snecma on a separate route when the objectives of the max thrust is lesser than what is requested for, and further on the point that considering engine as a single unit LRU, we either go total with firang or do it all by ourselves. We have the Ge414 to learn and if we are still unable to do so, so be it!. Let Kaveri come at a time when our team matures enough to handle turbine technology complexities.

No one including snecma would re-invent along with us, to just make us learn. They would only sell some parts, and those would remain secret for ever. your line of thought would not work and a waste of money on snecma. And finally, Mk2 for IAF is already seeing Ge414 orders. So, to make up the loss there, Snecma association all the way, to make the ECO core better and but not enough for Mk-2 is a gross negligence on the part of us to say, this partnership satisfy our objectives.

Kaveri all by itself has started to be successful. Now, next phase work on the 100kN, and deliver that to flight testing at gromov. Whatever needs for generating 100kN, Snecma will not and can't do from the open information about their core we can see.

Kakarat · Post by **Kakarat** » 27 Feb 2011 20:31

Gallery Updated

GTRE Booklet (16 Pages)

Added to Brochures section

arya · Post by **arya** » 15 Apr 2011 13:43

http://idrw.org/?p=1518
IAF still insists on Indigenous kaveri-MK2

Kailash · Post by **Kailash** » 15 Apr 2011 14:43

Is IAF genuinely concerned about the fact that we dont have a homegrown engine? If the focus is on indigenizing, "mostly indian" should be better than "nothing indian" right?

As usual they seem like a customer quoting requirements.

How much funds are they planning to put in? Show me the money..

How many engines they finally committing to buy, if requirement are met?
Where is the ownership and project management ? Are they putting in checks to ensure GTRE is on track this time - and report problems immediately?
How many variants do they need ? Tranches/improvement per tranche? Timelines and Roadmap?

Gurneesh · Post by **Gurneesh** » 02 May 2011 17:03

some good news

http://livefist.blogspot.com/2011/05/ka ... stone.html

Singha · Post by **Singha** » 02 May 2011 17:09

what kind of engine would the AMCA need? would a kaveri-snecma 90kN x 2 be enough?

to me it seems GE414 and its growth variant would power the Tejas mk1 and mk2 always and kaveri/snecma would not come near it
the kaveri-snecma would instead potentially power the AMCA intially and other such projects like single engine UCAV/drone in derated format...in meantime the raw kaveri can also be tested out on the Tejas as a flying testbed to prepare for next step which is upscaling it to a big motor in the 24,000lb class suitable for air dominance fighters. both streams of kaveri can cross pollinate each other...give it some other name like Arkavathy or Vaigai maybe.