- Pressure ratio is 27 instead of 24.5
- 31 in is inlet diameter not engine diameter and it's to increase airflow from 65kg/s to 72 Kg/s (certainlty with a margin to increase again if needed).
- Same thrust as EJ 200 in the same mass but with bypass ratio of 0.3 instead of 0.4 so with more thrust at high speed.
- Rafale have margin to increase size of engines.
And why is India not confident in its own capabilities to end the development?
@Picdelamirand-oil That is also something I don't understand. The entire Safran-Kaveri appears to be a conspiracy theory.
The way I see it is that India lacks rhenium to make anything better than 4th generation engine which requires 2nd gen and 3rd gen single crystal blades. So, if at all any help can be done, it is by supplying steady rhenium from france. I am not, however sure of this rhenium deficit and is just a guess.
Yes, I have seen the specifications of the M88 engine. It mentions clearly that it is 0.3 (Recheck the chart you posted). But now you say it is 0.4. I am not sure which figure is correct.
Let us look at the air inflow: 65 vs 72. With bypass of 0.3 and 0.4, the total air inflow via core comes out to be roughly the same - 50. While bypass is increased from 15 to 20 roughly. However, if the bypass is just 0.3, then I am not able to understand how it works out.
Next, the pressure increase has been noted. However, the temperature remains constant at 1850k (1600 degree celsius). This also raises questions. How is temperature constant when pressure increases? If the core is same, the volume will also be same and hence Pressure must vary with temperature.
The way I see it is that India lacks rhenium to make anything better than 4th generation engine which requires 2nd gen and 3rd gen single crystal blades. So, if at all any help can be done, it is by supplying steady rhenium from france. I am not, however sure of this rhenium deficit and is just a guess.
Yes, I have seen the specifications of the M88 engine. It mentions clearly that it is 0.3 (Recheck the chart you posted). But now you say it is 0.4. I am not sure which figure is correct.
Let us look at the air inflow: 65 vs 72. With bypass of 0.3 and 0.4, the total air inflow via core comes out to be roughly the same - 50. While bypass is increased from 15 to 20 roughly. However, if the bypass is just 0.3, then I am not able to understand how it works out.
Next, the pressure increase has been noted. However, the temperature remains constant at 1850k (1600 degree celsius). This also raises questions. How is temperature constant when pressure increases? If the core is same, the volume will also be same and hence Pressure must vary with temperature.
OK!
- 0.4 is EJ200 bypass ratio my aim was to compare M88 with EJ200 because you start to do it. The bypass ratio of M88 remain 0.3.
- The hottest part of an engine is not inside the core it is the turbine inlet so it is generally this temperature which is given as an indicator of the technology level of the engine. And this temperature doesn't change for the two versions of the engine.
I have answered that I am not sure if India ever asked for anything from anyone. This whole France-Kaveri could simply be a conspiracy theory or an exaggeration of minor item like consultancy and certification. India does not have its own certification agency whereas France does. So, for international sales, it will be better if the certification is from a reliable agency and hence India approached France. but some people with half knowledge might have started jumping around spewing conspiracy theories about Safranised Kaveri.
I am simply not convinced that there is any deal with France about assistance at all. One of the French delegation in India also recently confirmed that India and France haven't yet negotiated about any deals with Kaveri.
I am simply not convinced that there is any deal with France about assistance at all. One of the French delegation in India also recently confirmed that India and France haven't yet negotiated about any deals with Kaveri.
Manohar Parrikar confirms French help for revival of Indian Kaveri engine
By
Manu Pubby Feb 14, 2017, 03.48 PM IST
BENGALORE: The indigenous Kaveri fighter engine project is being revived with French help, with offsets from the Rafale fighter deal likely to be used to fund it, Defence Minister Manohar Parrikar has said, adding that India will requires a large quantity of engines in the future, including over 5,000 for helicopters itself.
Parrikar said that French firm Safran - which has developed the M88 engines for the Rafale – will be using technology from its engines that go on the Rafale to revive the Indian project. The minister has confirmed a story first reported by ET on July 4, 2016 about the Kaveri revival plan.
As reported by ET, leading manufacturer Safran has finalised a $2 million consultancy agreement to revive the project for combat planes and unmanned aircraft. French experts have studied Kaveri gas turbine project -- which was stalled in 2014 -- and have draw a joint development plan.
France has offered a one billion euro investment to revive the combat jet engine project, proposing a joint development plan to use offsets credits that will come from the Rafale fighter jet deal.
The Rafale deal has a offset obligation of 50 per cent of the contract cost, which translating into over 3 billion euros. Several rounds of discussions have already taken place between French company Safran and Indian developers since January.
The Kaveri engine project was more of less abandoned for aviation use in 2014 due to power shortcomings. While the consultancy agreement will lead to a detailed plan, initial assessments by French experts has brought out that 25-30 per cent more work is needed for it to get combat worthy.
Read more at:
//economictimes.indiatimes.com/articleshow/57145943.cms?from=mdr&utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst
What decides the temperature in combustion chamber or a cylinder in a piston engine? Its the fuel air ratio. As long as you keep this ratio constant and use the same fuel, the rise in temperature will be same.
Now when you increase the airflow thru the core, the fuel air ratio will reach a stage where it will not be able to sustain a flame, so you have to increase the fuel flow to maintain a combustible fuel air ratio. This increased fuel flow with increased mass flow increases the thrust but the SFC and TET remains same.
I hope this will clear all your doubts about jet engines. If you still have any, I will be more than happy to clear them.
We are struggling. After all the tech is one of the most difficult to master in the world.
Its not that we can never do it, but if a partner helps us with it, its obviously the better risk management approach.
In fact, risk management dictated that we should have had a development partner from the beginning. Of course geopolitical scene then was much different and most likely no western country (or even Russia) would have offered it.
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I understand this. My question is:
An engine is self sustaining in nature (using fuel supply). The air intake will depend on the amount of pressure created by the heat generated which in turn depends on the consumption of fuel. In other words, as the fuel consumption increases, the heat increases which makes the turbines run faster and hence attract higher airflow which in turn will generate higher thrust. The equilibrium temperature of the core increases with the increased fuel consumption and that sustains the higher fan speed and thus gives consistent thrust. This is the cycle of an engine.
So, the temperature of the core increases as the thrust increases. But the TET of a 75kN engine being same as the 90kN one is a surprise. The equilibrium TET of a 75kN engine must be lower than that of 90kN engine to justify the increased/decreased pressure to drive fan at a higher/lower speed to generate higher/lower thrust.
To simply speak, PV/T is the ideal gas equation and generally holds. Since V is constant (same core), P/T must also be a constant. If P increases, T must also increase to justify the increase in P.
Even 99% is not enough.
To produce a 4 strokes engine, you may have pistons, connecting rods, came shaft... if the cylinder head is missing, it doesnt' work !
This article appears dubious and is written by Manu Pubby who has his own biases. There is not one single quote nor is there any specific data about the assistance. I have found an article which has more details about the assistance:
Hopeful of flying Kaveri engine in next Aero India: DRDO
Hopeful of flying Kaveri engine in next Aero India: DRDO
Essentially, the assistance is only for certification. France is the second biggest aircraft supplier after USA and hence India considers the certification and consultancy from France as very valuable to add value to the engines.
Percentage is calculated based on qualitative and quantitative analysis. Just having the parts does not mean 100% completed. The completion will depend upon the integration too.
That is the reason that you have limits of Hot core. What constitutes hot core of the engine? Its the HP compressor, combustion chamber and HP, LP turbines. Ideally we look for 1:40 fuel to air ratio in jet engines. The mass flow can be increased by increasing the airflow by increasing the throat area or by increasing the RPM of the engine or by introducing water injection or by introducing water-methanol injection. The dry air density is higher compared to water vapours. There is a limit to increasing the RPM as the mass flow increases as the higher RPM is additional heat and the capture area also is not sufficient to absorb the whole mass flow/heat. The limits of hot core are written based on the limits of RPM, cooling, capture area and ability to convert them into useful energy.
When we say that M88 core is fit for 105KN it means that by increasing RPM to accommodate increased expansion of gases with larger airflow, the TET and efficiency of extracted work will remain constant upto this thrust level. If the thrust increases beyond that level, we will need to increase the capture area of the turbine for the increased mass flow and our failure to do so will result in excessive heating of the blades of the HP turbine resulting in meltdown and break off.
So we will need exotic material for it which can withstand higher temperatures like CMC or Rh which can withstand such high temperatures while being able to run at higher RPM with existing blade cooling tech and surface area.
have you driven a motorbike ever? Why do you have those wings on the cylinder head of the bike? Its to dissipate the heat. And when you go for big superbikes, you will find that they have watercooled engines. Why so? if a 100CC bike can have air cooling why do we need water cooling for superbikes? seems the guys who created lost their mind. Isn't it?
If we still had Parrikar as our RM, Mr Macron would not have visited India such stupid proposals. Even Modi wud have been shit scared to Host French President in the absence of the deliverable promises.
Your quote itself has the answer. I have quoted the same lines and have highlighted the answer in red below:
In a series of slides accessed by Livefist, the contours of the ‘Make in India’ elements of the Rafale deal stand revealed for the first time. The details that follow pertain principally to the Rafale platform itself, and doesn’t include the $1-billion partnership between France’s SAFRAN and India’s DRDO for the Kaveri turbofan engine, a major thrust area for both countries that will also count in the offsets program.