what was wrong with Kaveri Engine?

[Hulk]

One of the main problem of India's R&D is that they try to do it in government based companies. This is difficult as there is little to no motivation. Politics etc. Shifting to private sector is the key.

 

[zebra7]

Show me your kaveri engine power your LCA just one min in the air or rolling on the airfield for just one min then I answer your request.

You not even fit to ask me this question with your kaveri engine failure , Kaveri can't even make it to demonstration level on LCA , show how pathetic Indian jet technology is.

At least my video proves China is light years ahead of Indian in jet technology.

Dear Beast, this is the thread for Kaveri Engine and the aspects which is hindering the Kaveri to reach its ultimate goal or rather the revised ASR of IAF. When Kaveri was linked with the LCA, the GTRE did the study and find out that there is no other engine available of the required parameter, so GTRE was given the task for the development of the turbo fan engine in the country. As china is also working on the engines, and you know very well how much it is difficult to develop the engine of you own, because no other country or OEM is ready to give you the technology. The difference between Indian and Chinese efforts are the amount of budget allocated to the Engine development program and not the tallent and the idea to provide the indegenous engine tech.

China did develop WS-10A, but at what thrust, reliability, and cost. The problem with the China is same like India, that is the Mettalugical composition required and there is no hard and fast rule to get that. We have to fail, try, again fail, try to achieve, what the western world had hidden from the rest of the word. I appretiate the Chinese effort, but unlike China, India have an options of American, Russian, French Engine at present.

As far as the Kaveri is conserned, the Kaveri was developed with the low bypass engine tech, because the tech like crystal blade technology was not present in the country at that time, and without BLISK, they did reached the first desired goal, but then the requirement of the LCA increases, which needs more avionics, and the wt. of the aircraft increases, so LCA of powered with the Kaveri could fly, but with limited, thrust, and India have the option of other US engine which is available i.e F404 and F414INS which have more MTOW, and it suits the LCA, thus the Kaveri was delinked from the LCA, so that the delay could be avoided, but the parallel development continues with K-9 and K-10. So when Kaveri gets ready, it could be used in future.

So there is no benifit to make fun and baseless alegations, and we should appriciate each other effort, because the ultimate goal of both of us is self reliance in Engine Tech

 

[gslv mk3]

I guess India had ToT of the saturn engine powering mki

No,we can't breach IPRs.

Hmmm Made in India by Indians?

May be our products aren't as advanced as bangladeshi LCVP

 

[amardeep mishra]

3. India is yet to master the crystal blade technology from other peers

Hi dear @Skull and Bones
There are a lot of factual inacuracies in your post and in posts of other members as well,i will point out one by one and debunk some of the previously held misnomers-
1) Yes india has successfully developed metallurgical process to create first gen of single crystal blades circa 90s,but the world(other gas turbine manufacturing countries) has moved on to 3rd or possibly 4th gen of SCBs.In fact MIDHANI corp is the production agency for SCBs designed by DMRL

 

[Skull and Bones]

Hi dear @Skull and Bones
There are a lot of factual inacuracies in your post and in posts of other members as well,i will point out one by one and debunk some of the previously held misnomers-
1) Yes india has successfully developed metallurgical process to create first gen of single crystal blades circa 90s,but the world(other gas turbine manufacturing countries) has moved on to 3rd or possibly 4th gen of SCBs.In fact MIDHANI corp is the production agency for SCBs designed by DMRL

Sure, we are all here to learn. Much appreciated.

 

[amardeep mishra]

1. like all indian wepons it is a bit too heavy

2. has too many parts which increases workload for mantainence crews

3.doesnt have single crystal blade so has tendency to "throw" blades into turbine core when at very high tempratures

4.its core dosent have capacity to be efficient at tempratures above 1800 degree celcius when it needs to have cpacity to remain efficient even at tempratures in acsess of 2200 degree celcius (inside cumbustion core)

in short if indian sientists some how develop metallurgy/alloys for core that are not just light but can remain efficient in very high tempratures and single crystal blade same Kaveri engines that can produce 85 Kn now can easily achieve thrusts upto 95Kn+ and niether frenchies nor the russians or the europeans are ready to share that knowledge with us but if we make a deal with USA and mass produce there GE414EPE engines in india then USA is ready to share these techs with us and if we have these techs we can use these techs to produce any kind of high parformance gar turbine engiens in india

Where do you get your information from?Believe me it is laughable- especially the #3 is patently false!
The reason why itz fault tolerance is low is because of acoustic instability and i have explained it in various posts,i will re-iterate for all who failed to read my earlier posts-

Acoustic instability occurs when the frequency of flame in the duct(combustion chamber) matches with the natural frequency of the duct- this leads to resonance and compressive and tensile stress on the central shaft in longitudinal axis. Imagine a shaft rotating at 32000-50000 RPM and undergoing this!
This results in increased mechanical fatigue on the blades etc . At cross section 3 in picture above(HP blades),the temperature at 3A and 3* aint same and there exists a temperature gradient along the cross section 3.Temperature at 3* is greater than 3A.Hence the blade region at 3* should be made stronger than at 3A.If for some reason,that is not the case,then the blade will start developing creep from 3*

Interestingly i would also like to point out that two of the professors at IIT madras have filed a patent in PREDICTION of combustion instability in gas turbine engines.The trick to mitigate this,is to place the injectors in such a Manner that probability of combustion instability is reduced(obviously I'm talking about cam annular or annular arrangement)

 

[proud_indian]

@amardeep mishra

In your opinion what are the areas where we are lagging and realistically in what time frame can we expect them to overcome these deficiencies?

regards

 

[knight11]

Kaveri History: Well first-of-all, it’s erroneous to assume Kaveri (or GTX-35 VS) is the absolute first turbojet/turbofan to be designed/developed from the ground up (from scratch) by GTRE – it’s not. In fact Kaveri is not at all a “from the scratch” development in the first place – it more of an upgrade.

It’s predecessors were GTX-37 U (turbojet) -> GTX-37 UB (it’s turbofan version) -> GTX-35 (enhanced turbojet based on 37U tech). And Kaveri (or GTX-35 VS) is more of an upgrade of GTX-35 (same core etc.). The following schematic depicts the Kaveri lineage:

Note: How the reduction of HPC stages were carried out to reduce weight, while increasing the turbine efficiency by increasing TET (and OPR) simultaneously – all of these required adavcnes in materials tech as well. Also note, the mass-flow drop during graduating from a turbojet to turbofan necessitating further efficiencies in turbine and compressor technologies (or increase in the number of corresponding stages).
Pls note the 37 series is from 70s and early 80s while the 35 series from late 80s to early-mid 90s.

But all of these, still doesn’t make the above “lack-of-experience” argument completely void – as none of these predecessors actually flew and are more of a laboratory products (or tech demos).
Back in 1983, right after the LCA project was sanctioned, a concurrent engine evaluation study was conducted by GTRE - in 2 years time, in 1985, this was completed and the summary finding was "No contemporary engine is available world-wide that meets the LCA engine specifications".

F-404 etc were after-thought and more importantly, risk mitigating steps, which due to non-delivery of the actual engine, has now become the default engine.

Anyway, similarly a “Materials Committee” of GTRE in 1989, after a comprehensive study of various materials of contemporary turbo-jet/fan engines, and also after taking into account the infrastructure facilities available within the country in general and production capability of MIDHANI and DMRL, recommended the development of material, batch production and type certification process etc.

The Kaveri development programme was then launched in 1989.

The Kaveri itself (actually only the core, kabini) first ran in Mar 1995 and 2 Kabini prototypes (C1 and C2) and 3 full engine prototypes (K1, K2 K3) ran between 1995 and 1998.

Kaveri Design Choice Rational: With this historical background in place, IMVHO, I’d speculate that what really happened in 1990 or thereabouts, while the performance and (also materials roadmap) design for Kaveri were being finalized , is the designers and technologists of the GTRE were faced with a major dilemma:

• 
  1) On the design front,
  
  • 
    a. is it sensible to aim for the various core design parameters (e.g. OPR, TET, BPR, Combustor efficiency, supersonic compressor regimes, ultra-low aspect ratio blades, blisk manufacturing etc) of the various modern engine development programs in R&D
    OR
    b. to stick to the basic already understood basic design layouts of the GTX-37U and 37UBs and try and introduce medium-level of improvements on these design parameters and still meet the Kaveri specs.
  
  2) Similarly, on the materials front,
  
  • 
    a. Aim of the materials technology being worked on at various material design houses (e.g 2nd and 3rd Gen SCBs, DS based later-stage compressor blades, 1st gen SCB based , Ceramic and Polymer Matrix based combustors and static-engine parts etc etc) and provide a quantum jump in performance parameters that was being asked from Kaveri specs
    OR
    b. Provide a more conservative incremental advancement in material tech (e.g. introduce Dir Solidified blades for HPT, Ti and Ni based-equiaxed-casted Compressor blades, contemporary “bolted” disk and blade interfaces, annular combustor etc) and still achieve the Kaveri specs

It may be fashionable to attribute the GTRE folks as failures/worthless/losers etc , but the fact they had a fair idea about the contemporary advancements being carried out world-wide, to have made the design-choices that were made, then.

So the decision matrix then may have looked like:

1(a)2(b) ---|--- 1(a)2(a)
---------- Risk ------------>
1(b)2(a) ---|--- 1(b)2(b)

The GTRE technologists and designers chose 4th quadrant i.e. 1(b)2(b) – of course, with a hidden/inner ambition of getting to the 1st quadrant stuff concurrently and as the general technological level of the country advances in next 2 decades.


Overall Design Goals met/not-met: Pls, one word of caution towards over-emphasizing the success of dry-thrust, 90% wet thrust achievement (SFC, well, not sure) etc – yes those values are achieved, but at what weight (and maybe SFC also) penalty?

If you look at the chart above, a prev gen GTX-37UB also would have met these figures, isn’t it (with even more weight and SFC penalty).

So IMO right way of labeling Kaveri is to call it as qualified-success. As it, for the first time, if pursued with no let-up thru the flight-test-programme, will validate a flying turbofan engine – in technological terms it would
1) validate (and provide invaluable empirical data) the CFD and basic mechanical design of a twin-spool 80KN turbofan (90s level)
2) given enough design and manufacturing technological confidence of 80s level of material tech

Without these there’s no hope of leapfrogging technological gens etc (refer to epilogue section for a glimpse of that), and we're doomed to play catch-up forever.


Inference: But there-in lies the problem,
i.e. first, recall the findings of Engine evaluation study of 1985 which basically stated LCA engine specs are set high-enough to be met by a contemporary engine then. Now contrast that with the constraining technological choices (aka Conservative-Conservative) being made for Kaveri to achieve those.

This essentially means, there’s wafer-thin margin of error towards meeting both the core engine-design parameters and the enabling material/manufacturing design/technology. Even shortfall of one parameter may spell doom – and that’s precisely happened with Kaveri albeit shortfall in meeting almost all design parameters (admittedly, by small enough margin but big enough to all contribute to a compounding effect of the shortfall we see today).

But wait, before we start dishing out our advises, from our hindsight-is-20/20 vantage point, let’s try and think thru why would the GTRE folks not consider high-high risk of 1(a)2(a) approach.

Well, if you look at our national psyche of extremely naval-gazing, if-it’s-made-in-India-must-be-useless, pricing-of-tech-dev-in-terms-of-social-upliftment-missed-cost, 3-legged-cheetah-labelling-user-attitude etc. (Shivji will have a longer list), GTRE folks would be mortally scared of failures arising from such a high-risk endeavour.
Frankly, I’m not very sure if it mattered to the GTRE folks, if LCA flew or not, as long as they have met the Kaveri design parameters. So when the larger program, due to scope creep, necessitated a requirement growth of a next-gen powerplant, Kaveri in it’s present technological form is not even close to it.

Plus all this talk of new imported core etc means exactly that – a fully imported engine in terms of jet-engine tech, nothing more nothing else.

That’s the price to be paid for a pessimistic/stifling national outlook towards technological advancement with zero-tolerance towards failures and import at all cost attitude.

Epilogue: While we constantly continue to berate the GTRE folks for technological failure etc, a small bit of snippet needs understanding.

In mid-2000s, desperate to trying to reduce the overweight Kaveri (it’s still overweight by 150Kg or there-abouts), GTRE folks went ahead experimenting with the absolute cutting edge of material tech i.e. Ceramic Matrix Composites (CMC) and Polymer Matrix Composites (PMC) on some of the non-rotating-non-critical components. CMC was targeted towards a few hot-components like Nozzle divergent petals, exhaust cone etc – while PMC (high temp PMR-15 class) towards bypass duct, CD Nozzle cowls at the back etc.

The aim was to reduce weight by 30Kgs (i.e. approx. 20-25%).

In contrast, pls google around for CMC and PMC related R&D and, more importantly, it’s usage on various aero-engine by established western players.

This confidence and attitude are the true by-products of the Kaveri engine development program.