2012 Exhaust regulations and design possibilites

[horse]

One thought that struck me after thinking about the new exhaust regulations was the potential for using radiator waste as diffuser augmentation. I think it's been discussed before, but there must be some potential for "cold blowing" from the radiator exits replacing the current route that the exhausts use. I wonder if the current McLaren design would be more suited to this, given it is sort of longer and flatter, as it were. Probably significant cooling implications, but don't Renault almost do this, except they exit above the diffuser rather than to the sides.

[wesley123]

One thought that struck me after thinking about the new exhaust regulations was the potential for using radiator waste as diffuser augmentation. I think it's been discussed before, but there must be some potential for "cold blowing" from the radiator exits replacing the current route that the exhausts use. I wonder if the current McLaren design would be more suited to this, given it is sort of longer and flatter, as it were. Probably significant cooling implications, but don't Renault almost do this, except they exit above the diffuser rather than to the sides.

That wouldnt work if im correct.

I thought i read this somehwere that the exhaust flow is of high velocity and high energy thus can be used really effectively over and through the diffuser to generate downforce. The cooling air is not, this is effectively much lower speed and of less energy compared to exhaust flow. so 'dumping' the cooling flow into the diffuser is not efficient, actually you want to have none of that flow, that is why for example red bull dump it out of the back of the engine cover, they are blowing it in an area where barely anything happens.

Imo we can speculate that the way the renault is built that exiting it over the diffuser is actually aiding diffuser extraction but i think it is rather driven by making the beam wing more reachable for airflow

[horse]

Hmm, I certainly agree with you that the flow through the sidepods is nowhere near as energetic as the exhaust when under power. The counter argument for me is "cold blowing" when they are off the throttle. Surely this is just diverting air through the airbox and out the exhaust pipes? There is no retarded ignition so it is simply this process and the inertia of the engine which is driving the flow, I believe. Thus, what's so different about collecting air in the sidepod scooping and exiting them in a concentrated region about the exhaust. They will be hot and that will be beneficial. To me the RB7 cooling chasm is there as part of the tight sidepod philosophy, in that it minimises bodywork towards the rear of the car.

I'm not trying to claim that the RB8 would definitely do this - it doesn't seem very in keeping with the shrinking philosophy of the car - but I think there might be some parity between cold blowing and a concentrated sidepod exit.

[richard_leeds]

The difference is that cold blowing from the engine is pumped at high velocity by the engine. The energy is there, if you don't use it then it is wasted.

Meanwhile air passing through the radiators and under the engine cover has a tortuous path with no fan or pump to squirt it out the end. I imagine one could create a small nozzle at the exit to boost the velocity and create a jet, although that would have the dangers of building back pressure, hence reducing the cooling.

I'd have thought teams would want the internal air flow to be as low as possible to allow the body to be as tight as possible to allow more efficient external airflow to the rear.

[creedbratton]

Is there a minimum height at which the sidepod needs to be where the exhaust exits?

If not, then i can see the teams having the sidepods sculpted heavily downwards rather than sidewards, then having the periscope exhaust coming out maybe 100mm above the floor.

[richard_leeds]

The McLaren L pods might have an advantage in channelling the exhaust flow.

[munudeges]

One thought that struck me after thinking about the new exhaust regulations was the potential for using radiator waste as diffuser augmentation.

I have a feeling we'll see something more complex than that. Exhaust exits might be ending up further back but that doesn't mean that exhaust gas cannot still be used and channelled in various ways. Whereas in the past many engineers just wished the exhausts would go away and stop interfering with the aerodynamics, which was the thinking behind Ferrari's 'periscope' idea, the genie can't be put back into the bottle now. Exhaust gas on a Formula 1 car cannot be wasted.

If any team has breathed a huge sigh of relief and thinks they're going to beat Red Bull with simple periscope exhausts next year then they're going to be disappointed.

[horse]

The difference is that cold blowing from the engine is pumped at high velocity by the engine. The energy is there, if you don't use it then it is wasted.

The car is in gear, you're right, so in fact the rear wheels are driving the air through. I had forgotten about this action.

Meanwhile air passing through the radiators and under the engine cover has a tortuous path with no fan or pump to squirt it out the end. I imagine one could create a small nozzle at the exit to boost the velocity and create a jet, although that would have the dangers of building back pressure, hence reducing the cooling.

I'd have thought teams would want the internal air flow to be as low as possible to allow the body to be as tight as possible to allow more efficient external airflow to the rear.

I admit, it's not a very nice solution, but it was the only way I could think for doing any diffuser augmentation with next years rules. In general though, I'm not too sure what exhaust gases exiting on the top of the bodywork would be good for. Drag reduction maybe? It'll certainly be interesting to see if there are any special interpretations.

[beelsebob]

[exaust pipes must be cylindrical in cross section and posibly have a standardised diamater, not to mention exit 300mm rearward of the rear wheel centre line i think will have an impact on the packaging for 2012.

They've cancelled that scheme due to the length of the pipes. The 2012 rules will require a traditional periscope out of the top of the sidepod. Not sure what that'll do to McLaren L pods/quote]
To be honest – it might make them work rather well – periscope the gas out the high bit at the end and you create an artificial wall keeping the air flowing in the channel for even longer.

[MIKEY_!]

I know i'm just the new guy here but the exhaust will surely blow onto the tire with this config - we all saw the problems that gave Benz this year.

[Coefficient]

I know i'm just the new guy here but the exhaust will surely blow onto the tire with this config - we all saw the problems that gave Benz this year.

I think all the teams have plenty of recent experience with the periscope exhausts and generally they were positioned well in board, blasting the beam wing. I doubt the teams will unwhittingly run into unforseen problems through this rule change.

[wesley123]

sure the merc will, these guys have problems for the last 3-4 years no other team has lol

[MIKEY_!]

Any word on what the rules for the positioning will be, how high, how far back, even angle of exit could be vital.

[MIKEY_!]

How effective would using rad air to replace the exhaust in the diffuser skirts be. Or is the temp/flow rate far to low.

[raymondu999]

I assume you mean to replace the way the teams are currently using the exhausts as air skirts?

It would be much less effective IMO. A lot of energy is lost from the gasses as it goes through the various obstacles it has to go through inside the engine cover; as well as the rad fins. You could look in the early pages of the R31 thread as people were discussing the way the rad exhaust was being directed in a flat hole at the car's rear right on top of the diffuser, blowing over the top of the diffuser with the exhaust air.