Kaveri Engine

[BON PLAN]

A recent tender by GTRE calling for



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For those who think GTRE is doing nothing

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It is for what kind of plane? A single air intake, it seems dorsally mounted.... A drone?

 

[Gessler]

It is for what kind of plane? A single air intake, it seems dorsally mounted.... A drone?

Yes, a project called Autonomous Unmanned Research Aircraft (AURA). Much like Taranis/nEUROn in looks. Also called IUSAV.

 

[sasum]

The road is long...

Safran (Snecma in fact) has a lot of problem with it's new business jet Silvercrest to day. 3 years late on shedule! That means even for a well established producer, it's some times hard to go on a new market (with a new product). So for you it will be even harder. But not impossible.

This I believe is a relatively smaller engine of 35Kn thrust. Kinds trainer Jets use. What kind of snag encountered? Snecma is vastly experienced... seems spooky.

 

[BON PLAN]

This I believe is a relatively smaller engine of 35Kn thrust. Kinds trainer Jets use. What kind of snag encountered? Snecma is vastly experienced... seems spooky.

A problem of cooling.
Lubricant is cooled by gasoline in a exchanger, which is a molded part. It was not efficient enough.
This exclanger had to be redisigned, with a long lead time (redesign of mould, new parts, tests, certification...).

This engine is rated 42 to 53 kn. It seems may be too easy for Snecma .....

 

[sasum]

A problem of cooling.
Lubricant is cooled by gasoline in a exchanger, which is a molded part. It was not efficient enough.
This exclanger had to be redisigned, with a long lead time (redesign of mould, new parts, tests, certification...).

This engine is rated 42 to 53 kn. It seems may be too easy for Snecma .....

Is gasoline the best coolant for a jet engine? It is fine at high altitude becoz it freezes only at -50°C. But if we operate such Engines in May/ June in Rajasthan Sector...what is the coolant in M88 (Rafale), gasoline?
Btw, I thought Silvercrest engine produced 8000 pound thrust. That is roughly 35 Kn.

 

[warrior monk]

It is for what kind of plane? A single air intake, it seems dorsally mounted.... A drone?

Not sure but the looks of it seems to have 3 stage axial flow LP compressor and the six stage axial flow HP compressor and curiously it doesn't seem to have any radial ring afterburner though I can see the flame stabilizer ,probably not have any wet thrust so it is probably a non afterburning turbofan which seems curiously like kabini core . So I think its for some kind of ucav . I'm just guessing

The road is long...

Safran (Snecma in fact) has a lot of problem with it's new business jet Silvercrest to day. 3 years late on shedule! That means even for a well established producer, it's some times hard to go on a new market (with a new product). So for you it will be even harder. But not impossible.

Collaboration is the way to go even Onera of France which has developed the AM1 SCB superalloy used in the M88-2 Snecma which powers Rafale collaborates with Turbomeca, EDF, SIEMENS , Howmet UK and the Hahn Meitner Institute Berlin for industrial application for next generation superalloy. Even if it is not for military .

 

[Chinmoy]

I read somewhere, in modern warplanes, pitch, roll & yaw are controlled by a computer algorithm (part of avionics suite). In older aircrafts like Mig-21, these were juggled manually by pilots employing hydraulic-mechanical controls requiring considerable skill. Now, think when a fighter jet takes off with equal no. of missiles (equally distributed weight) under each wing, it is well balanced. When pilot fires one, that side becomes lighter and the plane tends to roll. It is the FCS which comes into play & constantly adjusts plane's orientation.
Can't the same adjustment be done with firing engines?

Talking about weight, a missile does tip the balance in a few hundred of KILO, but with engine, you are talking about TON. Moreover, the real challenge would be the Fluid dynamics or the Aero dynamics. Just think about the stress it would have on the structure with a engine slung on its belly.

 

[sasum]

Fluid dynamics or the Aero dynamics. Just think about the stress it would have on the structure with a engine slung on its belly.

Fluid dynamics will not be affected..the engine will not be tethered loosely to the body like a kite. Pressure, viscous force ,specific gravity, turbulence will be same as engines hung from wings as in passenger jets. Modern fuel injection and combustion are computer controlled to take care of these variables.
But yes the air frame may experience greater metal fatigue from vibration. Composite material -- light & strong may solve the problem.

 

[Chinmoy]

Fluid dynamics will not be affected..the engine will not be tethered loosely to the body like a kite. Pressure, viscous force ,specific gravity, turbulence will be same as engines hung from wings as in passenger jets. Modern fuel injection and combustion are computer controlled to take care of these variables.
But yes the air frame may experience greater metal fatigue from vibration. Composite material -- light & strong may solve the problem.

Here you can't simply compare an airliner structural integrity with that of a Fighter. Both do have a different approach towards vortex formation and countering it in its flight. While both are streamlined to face minimum drag but while Fighter is build with relax static stability in mind an airliner is made with positive stability.
Means if you have to test an engine in that manner, instead of doing it in a fighter, you would have to do it in a traditional aircraft.

 

[PaliwalWarrior]

Nope..:biggrin2: BHEL routinely installs gas turbines for power generation. Railways tried gas turbine on a modified loco in 2010.

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It was tried by Russia way back in 1960 I think

 

[sasum]

It was tried by Russia way back in 1960 I think

Yes...............................

...........

 

[Screambowl]

Is gasoline the best coolant for a jet engine? It is fine at high altitude becoz it freezes only at -50°C. But if we operate such Engines in May/ June in Rajasthan Sector...what is the coolant in M88 (Rafale), gasoline?
Btw, I thought Silvercrest engine produced 8000 pound thrust. That is roughly 35 Kn.

The gasoline cannot cool sufficiently because the gasoline is itself kept warm in the tanks located inside wing with the help of heaters. Because even in aviation turbine fuel, the water traces are there. Hence if the temperature falls even below zero this water freezez and becomes ice , thus can block the fuel inlet and cause engine failure.

 

[BON PLAN]

The gasoline cannot cool sufficiently because the gasoline is itself kept warm in the tanks located inside wing with the help of heaters. Because even in aviation turbine fuel, the water traces are there. Hence if the temperature falls even below zero this water freezez and becomes ice , thus can block the fuel inlet and cause engine failure.

In the Silvercrest case, fuel is the coolant of lubricant, not of all the engine.
Sivercrest is more powerfull : up to 53 kn.
Some (or all?) rocket liquid engines use fuel to cool the engine just before being burnt.

 

[Screambowl]

In the Silvercrest case, fuel is the coolant of lubricant, not of all the engine.
Sivercrest is more powerfull : up to 53 kn.
Some (or all?) rocket liquid engines use fuel to cool the engine just before being burnt.

solid rocket moter dont require coolant. liquid ones which use lox and LN which are kept at close to absolute temp are also used as coolant.

but in modern jet engines, fuel is rarely used as coolant or never, even coolant of lubricant the fuel is not very effective.. The outside air is the best coolant, that's why they have duct bypass for.

For pre heating, the fuel is pass through some part of engine, that some how works as partial coolant

 

[BON PLAN]

solid rocket moter dont require coolant. liquid ones which use lox and LN which are kept at close to absolute temp are also used as coolant.

but in modern jet engines, fuel is rarely used as coolant or never, even coolant of lubricant the fuel is not very effective.. The outside air is the best coolant, that's why they have duct bypass for.

For pre heating, the fuel is pass through some part of engine, that some how works as partial coolant

Oups! sorry! Liquid engine.
Exhaust nozzle in particular is cooled by fuel in some.

 

[sasum]

solid rocket moter dont require coolant. liquid ones which use lox and LN which are kept at close to absolute temp are also used as coolant.

but in modern jet engines, fuel is rarely used as coolant or never, even coolant of lubricant the fuel is not very effective.. The outside air is the best coolant, that's why they have duct bypass for.

For pre heating, the fuel is pass through some part of engine, that some how works as partial coolant

Both compressor & turbine blades have rotor bearings. They are located within sealed bearing compartments. Lub oil supplied by the pressure pump is directed through individual supply lines and sprayed on the bearings through one or more nozzles per bearing. Figure below shows the arrangement of the oil nozzles for the front ball bearing of a CFM56-3 turbo fan engine. The oil-wet areas are only inside the bearing compartments.
The oil has no contact with the rotor components outside the bearing compartments and to the gas path. To ensure this the walls of the bearing compartments are sealed against the rotating shafts. Lub oil on its way back to oil-tank is cooled by some coolant which i don't know.

 

[BON PLAN]

Both compressor & turbine blades have rotor bearings. They are located within sealed bearing compartments. Lub oil supplied by the pressure pump is directed through individual supply lines and sprayed on the bearings through one or more nozzles per bearing. Figure below shows the arrangement of the oil nozzles for the front ball bearing of a CFM56-3 turbo fan engine. The oil-wet areas are only inside the bearing compartments.
The oil has no contact with the rotor components outside the bearing compartments and to the gas path. To ensure this the walls of the bearing compartments are sealed against the rotating shafts. Lub oil on its way back to oil-tank is cooled by some coolant which i don't know.

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In the Silvercrest case, at least part (but I think all) of lubricant is cooled by fuel.

 

[sasum]

For pre heating, the fuel is pass through some part of engine, that some how works as partial coolant

In a turbo fan engine, fuel (kerosene ?) is injected through a nozzle in combustion chamber. Fuel never travels to any other part of the shaft or blades. You may be talking of cooling liquid rocket motor.

 

[Screambowl]

In a turbo fan engine, fuel (kerosene ?) is injected through a nozzle in combustion chamber. Fuel never travels to any other part of the shaft or blades. You may be talking of cooling liquid rocket motor.
View attachment 7992

Both compressor & turbine blades have rotor bearings. They are located within sealed bearing compartments. Lub oil supplied by the pressure pump is directed through individual supply lines and sprayed on the bearings through one or more nozzles per bearing. Figure below shows the arrangement of the oil nozzles for the front ball bearing of a CFM56-3 turbo fan engine. The oil-wet areas are only inside the bearing compartments.
The oil has no contact with the rotor components outside the bearing compartments and to the gas path. To ensure this the walls of the bearing compartments are sealed against the rotating shafts. Lub oil on its way back to oil-tank is cooled by some coolant which i don't know.

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there are many types of engines with different concepts and different needs. Every chamber requires cooling differently. And not just chamber but the blades too. So there are different methods to cool them.
Liquid cooling is less adaptive in military application, because coolant adds to weight.

 

[sasum]

there are many types of engines with different concepts and different needs.

Here we are talking only about Turbo-fan jet engine which is of same design for civilian as well as military use. Only difference is military engine may add an after-burner for additional thrust at the cost of fuel economy and noise. Nozzle vectoring may be another one.

Every chamber requires cooling differently. And not just chamber but the blades too.

We are not talking about cooling chambers in jet engine which in any case is done by air. We are talking about cooling lubes. Lubes are required for the bearings attaching shaft to the rotating blades.