McLaren MP4-31 Honda

[Jackles-UK]

All this talk of exhaust pylon wizardry is a bit of a nothing argument if you ask me.

In the V8 era where you had the plume from naturally aspirated engines revving consistently and predictably at around 19,000rpm with no interference from the system the energy that could be harvested was huge. So much so in fact that once the EBD was outlawed teams were still able to direct the flow through thin air with their coanda systems (McLaren/Red Bull most effectively).

However with engine displacement now 33% smaller, cylinders dropped by 25% and only revving to a maximum of 15,000rpm the amount of energy created by the exhaust has dropped massively. Couple this to the fact the the flow (already hugely reduced from past iterations) has now also got to spool up an enormous turbo and you realise the the amount of energy that could actually be harnessed would be so small it would, in my opinion, be so small as to make the expensive process of chasing gains from it totally insignificant.

[basti313]

Why do people think the pillar is there for some kind of aerodynamic purpose. I can think of two far more plausible reasons:
1. The original support in the exhaust was bending and allowing the rear wing to flex, therefore a thicker support was added into during testing as a stopgap measure until a better and stronger design can be made.
2. It is placed there to test the effects of back pressure, temperature of the exhaust gas or to see how back pressure effects the engine.

I'll go with the former reason if I were a betting man.

I do not think this is reasonable. We are talking about a diameter of 4-5cm, just by comparing its size to the minimal sizes of the wastegate exits. A support for the rear wing, which needs 4cm, is not reasonable. It would be smaller if they go to the next tool shop and weld something together in 5min...
Just for testing backpressure effect they also would not do welding somewhere in the middle of the exhaust pipe. They would use an easy solution...and of course this is nothing you test on the circuit, but on the bench.

Looking at it, it is highly unlikely that placing that there will have any meaningful positive effect of the exhaust flow. If you wanted to turn the exhaust flow upwards you would use a horizontal vane and it will have to be close to the edge of the exhaust. A vane placed so far in will have exactly zero effect on its direction as the exhaust flow will straighten pretty much immediately after.

I can totally agree with the point, that using this pillar or whatever to direct the flow upwards is not reasonable as it is too far away from the exit. And a vane closer than 15cm to the exit is not allowed by the rules.
Nevertheless shaping the flow from turbulent to laminar or vise versa is still possible and reasonable at this point.

[basti313]

....... Couple this to the fact the the flow (already hugely reduced from past iterations) has now also got to spool up an enormous turbo and you realise the the amount of energy that could actually be harnessed would be so small it would, in my opinion, be so small as to make the expensive process of chasing gains from it totally insignificant.

Well, this is your opinion. But looking at solutions in F1 tells us, that they are using every little bit of hot air they can get for aero. And exhaust flow is in the first iteration just hot air. Looking at this and not doing strange energy calculations, the turbo is not harming the amount of hot air blown through the exhaust at all and, of course, it is not taking much heat away.
And talking about usability: In the V8s you had strongly different exhaust blowing scenarios depending on the throttle. Vettel was an expert on using these. But with the V6 turbo...there is much less difference between on- and off-throttle blowing, as the turbo driven by the MGU-H off-throttle is leveling this.
So in summary I think that it totally reasonable to use the exhaust gases for aero reasons also on the V6 turbo whenever it is possible.

[bonjon1979]

....... Couple this to the fact the the flow (already hugely reduced from past iterations) has now also got to spool up an enormous turbo and you realise the the amount of energy that could actually be harnessed would be so small it would, in my opinion, be so small as to make the expensive process of chasing gains from it totally insignificant.

Well, this is your opinion. But looking at solutions in F1 tells us, that they are using every little bit of hot air they can get for aero. And exhaust flow is in the first iteration just hot air. Looking at this and not doing strange energy calculations, the turbo is not harming the amount of hot air blown through the exhaust at all and, of course, it is not taking much heat away.
And talking about usability: In the V8s you had strongly different exhaust blowing scenarios depending on the throttle. Vettel was an expert on using these. But with the V6 turbo...there is much less difference between on- and off-throttle blowing, as the turbo driven by the MGU-H off-throttle is leveling this.
So in summary I think that it totally reasonable to use the exhaust gases for aero reasons also on the V6 turbo whenever it is possible.

[PhillipM]

What kind of exhaust temperature do you think they run post turbine?

Well, it's not uncommon to see the interior of the exhaust where the pylon is glowing dull red, so probably still north of 500*c

[vdemeter]

I say it is to control wing flex using heat. When it is cold it is stiff and pases the flex test. When it is hot it flexes...

[motobaleno]

Also ferrari is using it
https://twitter.com/tgruener/status/707933738844426240

so it is hardly just a test but more likely a n already well defined solution

[hollus]

If all teams are running the minimum allowed exhaust diameter (which they are) it is because the ideal diameter would be even smaller.
So a blockage should help. I don't know exactly why it helps, but it should help. It's 3 teams now. Soon to be 11, I guess.

[PhillipM]

I say it is to control wing flex using heat. When it is cold it is stiff and pases the flex test. When it is hot it flexes...

I didn't see that as viable last year when someone suggested it for TR, I still don't, not with the size of the support. If you wanted to do that you wouldn't run the support but instead make the exhaust tube structural as it would be far less stiff and could deflect more. Plus if you deflected the upper half the of the exhaust tube you could entrain gases upwards.

However with engine displacement now 33% smaller, cylinders dropped by 25% and only revving to a maximum of 15,000rpm the amount of energy created by the exhaust has dropped massively. Couple this to the fact the the flow (already hugely reduced from past iterations) has now also got to spool up an enormous turbo and you realise the the amount of energy that could actually be harnessed would be so small it would, in my opinion, be so small as to make the expensive process of chasing gains from it totally insignificant.

Cylinders dropped doesn't matter, displacement is smaller and revs are lower yes, but then you're now pushing a couple of bar of boost into the motor compared to previously, and the motors aren't far off the same outputs as the old N/A's whilst running much leaner, so the net flow is going be similar.
You do have less energy in the flow from the turbine, but the elaborate monkey seat designs introduced immediately after the exhaust was mandated shows you there's more than enough there for teams to utilise it.

[PhillipM]

I'm going to apologise in advance for this terrible, terrible effort at Paint CFD

However, I still think it's doing this. I just don't think the effect is anything massive like actually blowing the seat, etc, is - perhaps it just makes things a bit more stable/flow less likely to detach at the rear.

[DiogoBrand]

Cylinders dropped doesn't matter, displacement is smaller and revs are lower yes, but then you're now pushing a couple of bar of boost into the motor compared to previously, and the motors aren't far off the same outputs as the old N/A's whilst running much leaner, so the net flow is going be similar.
You do have less energy in the flow from the turbine, but the elaborate monkey seat designs introduced immediately after the exhaust was mandated shows you there's more than enough there for teams to utilise it.

But they still are burning less fuel, and exctracting pretty much all the energy they can from the exhaust at the turbine. If the exhaust flow had a considerable amount of energy to it they surely wouldn't be blocking half of the exhaust pipe.
Edit: And the monkey seats weren't introduced after the introduction of this exhaust placement, they were introduced (or re-introduced, as I believe they were invented in the early 2000's) after the beam wings were banned, as a way to connect the airflow from the rear wing to that of the diffuser.

Someone guessed on the SF16-H thread that this is just heat protection for the DRS components, to me that's the theory that makes the most sense right now.

[PhillipM]

Edit: And the monkey seats weren't introduced after the introduction of this exhaust placement, they were introduced (or re-introduced, as I believe they were invented in the early 2000's) after the beam wings were banned, as a way to connect the airflow from the rear wing to that of the diffuser.

That's not what I said.
Monkey seats got a lot more elaborate and used a lot more when the exhaust was mandated to that area, as it uses the exhaust plume as well as the airflow over the seat to link the diffuser with the rear wing flow. So even though it's a very inefficient piece in itself, overall it started to provide more benefit than before with the side exhausts.
We now have very complex 3-4 element monkey seats which are shaped to run as close to the exhaust plume as legally possible.

[giantfan10]

I'm going to apologise in advance for this terrible, terrible effort at Paint CFD

However, I still think it's doing this. I just don't think the effect is anything massive like actually blowing the seat, etc, is - perhaps it just makes things a bit more stable/flow less likely to detach at the rear.

http://img.photobucket.com/albums/v89/R ... Vortex.jpg

You are correct... i read one one of the italian sites ( i forgot which one ) that the rear wing mount through the exhaust on the Ferrari is being used as a flow conditioner.

[Big Mangalhit]

What kind of exhaust temperature do you think they run post turbine?

Well, it's not uncommon to see the interior of the exhaust where the pylon is glowing dull red, so probably still north of 500*c

I doubt that value. In the leaked picture of Ferrari engine telemetry (Ferrari power unit thread) we could see the Texhaust left and Texhaust Right to be 282ºC and 300,5ºC. Because these are left and right I imagine that are on the exhaust manifolds right after the ICE so the turbine will extract work/heat of these values and some more energy will dissipate into the materials so I imagine the air coming out of the exhaust is probably a lot, really a lot colder that 500ºC

[Webber2011]

What kind of exhaust temperature do you think they run post turbine?

Well, it's not uncommon to see the interior of the exhaust where the pylon is glowing dull red, so probably still north of 500*c

I doubt that value. In the leaked picture of Ferrari engine telemetry (Ferrari power unit thread) we could see the Texhaust left and Texhaust Right to be 282ºC and 300,5ºC. Because these are left and right I imagine that are on the exhaust manifolds right after the ICE so the turbine will extract work/heat of these values and some more energy will dissipate into the materials so I imagine the air coming out of the exhaust is probably a lot, really a lot colder that 500ºC

Wasn't it decided that the telemetry was taken in in the garage at idle though ?
How much difference in exhaust heat would be seen at full power ?

I've got no idea !

Just wondering