Thread on Kaveri Issues IAF killed Kaveri successfully with their constant changing requirements, one of my colleagues who met with Mohan Rao clearly stated, "it was out of their control" angry they had been blamed for something that wasn't even their fault.

The bypass ratio of Kaveri is 0.18 achieved, and will need to be increased to 0.35 to 0.45 to achieve new requirements. That will need an increase in fan diameter, redesign of airfoil and wider chords, core flow reduction, redesign of bypass duct and more.

46.8 kN of thrust was achieved at dry setting and 7000 kgf with ab (3% shortfall before requirement change) Overall pressure ratio of 21.5 LPC Pressure Ratio is 3.4, surge margin > 20 HPC Pressure Ratio is 6.42, surge margin > 21.6(tip speed -370m/s) Combustor eff > 99%

Pattern factor of 0.35 and 0.14 These are achieved specs, ignore the brochure numbers. Kaveri has also been tested for bird hit, 85% thrust after bird hit at mach 0.5

Again the major reason was the lack of test facilities, Kaveri had issues with strain and blade throws. They tried to figure out the cause on ground bench but failed, only after they took it to CIAM, Russia. Non Intrusive Strain Measurement tests were done and they realized+

there were vibrations of the 3rd order of engine frequency. This took 3 yes because no testbed in India It was also only at AneCom, did they test the compressor and realized, 1st and 2nd stage were surged by 20%, while rest were practically useless

Then afterburner tests again at CIAM, the goal was 50% boost over dry thrust (dry thrust+50%) at 88% efficiency but only dry thrust was achieved The engine was taken again after sometime and certificated at 15 km altitude

Kaveri FADEC with manual backup is certified. Fan was also successfully tested at CIAM, Info about compressor: 6 stage, axial flow, corr tip speed (linear velocity of a compressor blade's outermost edge, representing how fast the tip travels through the air) is 370m/s

Mass flow of 24.13 kg/s (24.3) Pressure 6.42 (6.38) Efficiency 85.4(85%) Surge 21.6 (20%) Values in braket are design ones and ones outside are achieved values Multiple Combustors were designed, K8v4 was closet

Turbine: Pressure 3.6 Mass flow function 1.1 Max TET 1700K Eff 85% Kaveri LPC 10312 rpm, (13200 rpm for F404)

Now coming to Kaveri 2.0, what can be done to increase thrust? Larger inlet core dimensions? But sfc goes up Adding more hpc stages will lead to weight and core redesign issues The best way is to increase RPM, but that will require more work from HPT, which will need higher+

TET, that will need better cooling tech, 15% improvement can be done here. Should be explored

HPC will need wide chord, tip speed of mach 1.6, spr 2 Weight reduction will need to be done here, blisk will reduce it by 30% Also new HPC materials are needed, y-Tial CMC stages could be explored but I doubt we have that kind of maturity in tech yet

LPT improvement need again rpm increase, lighter lpt blades, new materials Better LPC design is needed, f404 LPC spins at 13k Kaveri at 10k 15-20% gain is possible without major redesign, just incremental changes, 73 kN can go to 85 A couple more versions needed k11, k12