Post-Turbo exhaust design

[aussiegman]

Oh come on, us lawyers aren't that bad!!!

That said I absolutely agree the FIA gave us a set of regs that don't leave much room for creativity on the engine package side.

Aero dominance will continue so at least Mr.Newey will be happy.

[Holm86]

The Rankine wouldn't propel the car. It would assist the turbo. The turbo does not propel the car just as the fuel pump does not propel the car.

Maybe OK maybe I am casting a wide definition, however regardless, I still think it is excluded under 5.2.1.

Nevertheless, it is excluded by every other aforementioned regulation.

In short, no Rankine device or system is allowable anywhere to drive the car, the turbine, the compressor or to provide WHR anywhere.

As a side, a fuel pump is not an energy recovery system such as a Rankine WHR system. It is a mechanical or electrical device for the purpose of fluid transfer or movement. A Rankine specifically recovers energy that is use by the vehicle to propel it forward, either directly of indirectly. In the end the energy directly recovered propels the car. Different to a fuel pump but sure.

The fuel pump delivers the fuel to the engine. The turbo delivers the air. So if the turbo propels the car so does the fuel pump. The turbo is already driven by waste heat of the engine. So if you had some additional form of WHR system to drive the turbo why would that be illegal?? The WHR cycle could be incorporated in the cooling system. Taking hot cooling water and run it through a coil that's wrapped around the final piece of the exhaust evaporating the water. Then using the steam in a turbine to aid the turbo. And the condensing the steam in the radiators. This would give some extra energy for the MGU-H to harvest.

[rjsa]

Taking hot cooling water and run it through a coil that's wrapped around the final piece of the exhaust evaporating the water. Then using the steam in a turbine to aid the turbo. And the condensing the steam in the radiators. This would give some extra energy for the MGU-H to harvest.

Whatever power you gain from this wouldn't offset the aero cost of the extra cooling.

[Tommy Cookers]

the turbine is sensitive only to about 40% of the waste energy in the exhaust (even at 2014 CR with unlimited Octane no fuel)

WHR is sensitive to the remaining 60% in the exhaust (plus an even greater amount of energy in the coolant)
IIRC judgihg by the developed BMW Turbosteamer it would be about 15% efficient (potentially 15% of about 700 hp of waste) ?
though bulky, heavy and very demanding of cooling (condensing)

but the rules were not intended to allow it ?

[rjsa]

And lets not forget the whole new set of problems from the increased pressure in the engine colling system.

[Holm86]

What increase in pressure??? Pressure will be absorbed by the turbine and pressure drops when the steam is condensed.

[ringo]

As for the exhaust pipe, it will be diverging up to that last 100mm or whatever the rulese say, then be constant diameter to the end. This will still act like a diffuser and increase the turbines pressure ratio, increasing efficiency.

On the outside of the pipe after the turbine, there will be cooling fins, lots of cooling fins. The aim is to drop the gas temperatures inside the pipe trying as best as possible to get some amount of condensation to further reduce pressure inside the exhaust.

[Holm86]

As for the exhaust pipe, it will be diverging up to that last 100mm or whatever the rulese say, then be constant diameter to the end. This will still act like a diffuser and increase the turbines pressure ratio, increasing efficiency.

On the outside of the pipe after the turbine, there will be cooling fins, lots of cooling fins. The aim is to drop the gas temperatures inside the pipe trying as best as possible to get some amount of condensation to further reduce pressure inside the exhaust.

That would be another advantage of that WHR system. It would cool the exhaust temperature after the turbine. Taking energy from it to produce steam.

[flynfrog]

As for the exhaust pipe, it will be diverging up to that last 100mm or whatever the rulese say, then be constant diameter to the end. This will still act like a diffuser and increase the turbines pressure ratio, increasing efficiency.

On the outside of the pipe after the turbine, there will be cooling fins, lots of cooling fins. The aim is to drop the gas temperatures inside the pipe trying as best as possible to get some amount of condensation to further reduce pressure inside the exhaust.

there will be no cooling fins on the downpipe. I doubt they will bother to polish the inside of the pipe either. After a few seconds at load that polish wont exist anymore anyway.

[aussiegman]

There can be no WHR system under the regs and it would be to heavy and bulky.

And I agree with the flynfrog, no polish and no fins, there is simply no upside for using them.

[rjsa]

What increase in pressure??? Pressure will be absorbed by the turbine and pressure drops when the steam is condensed.

You need to push water into the heating phase of the process, so you have to match the turbine input pressure.

[WhiteBlue]

As for the exhaust pipe, it will be diverging up to that last 100mm or whatever the rulese say, then be constant diameter to the end. This will still act like a diffuser and increase the turbines pressure ratio, increasing efficiency.

On the outside of the pipe after the turbine, there will be cooling fins, lots of cooling fins. The aim is to drop the gas temperatures inside the pipe trying as best as possible to get some amount of condensation to further reduce pressure inside the exhaust.

there will be no cooling fins on the downpipe. I doubt they will bother to polish the inside of the pipe either. After a few seconds at load that polish wont exist anymore anyway.

Can you elaborate a bit on the assumptions that led you to that conclusion?

[flynfrog]

As for the exhaust pipe, it will be diverging up to that last 100mm or whatever the rulese say, then be constant diameter to the end. This will still act like a diffuser and increase the turbines pressure ratio, increasing efficiency.

On the outside of the pipe after the turbine, there will be cooling fins, lots of cooling fins. The aim is to drop the gas temperatures inside the pipe trying as best as possible to get some amount of condensation to further reduce pressure inside the exhaust.

there will be no cooling fins on the downpipe. I doubt they will bother to polish the inside of the pipe either. After a few seconds at load that polish wont exist anymore anyway.

Can you elaborate a bit on the assumptions that led you to that conclusion?

Sure fins- not enough airflow in the area not enough cooling potential to make it matter. The pressure drop ringo thinks this will cause is right around nil. You need to look at the shear amount of heat energy coming out of the pipe even if the fins did work it wont take long to heat soak the entire area. Its would also be a perfect area to cause fatigue due to uneven heating and cooling of the inconel. The polished surface? Take any polished alloy you want then subject it to steam in the 600F region and high velocity add in possible combustion in the area and the polish wont last long. Look inside of any exhaust pipe ever after a race.

[ringo]

You have no evidence on such a strong position.
I was never referring to steam, and as for a polished surface not lasting long i don't know how you come to that conclusion.
If a pipe has a surface roughness, that roughness won't increase over a 2 hour period because hot air is blowing through it.
The inside of the pipe needs to be as smooth as possible.
This is the case for any diffuser system.
As for the fins, regardless of how small an advantage it is in pressure drop, it is still an option. You must take every advantage that you can get to increase turbine pressure ratio.

People don't recognize this, but the reason a steam turbine is so efficient is because the condenser operates pretty close to absolute vacuum. It does this by condensation of the steam to water. If the steam in vapour phase drops out of the atmosphere you reduce the amount of gas particles, thus reducing pressure.
Any chance of cooling exhaust after the turbine should be looked into.

[WhiteBlue]

This would speak for water injection into EGR if you can get it past the technical delegates. The jury on that is still out as far as I'm concerned.