Angled radiators.

[coaster]

How effective are the angled radiators in F1?
It looks as though the cooling fins are not in line with the flow of air, how big an issue would this be?

[olefud]

Depends. The fins could be parallel to the slip stream even though the radiator is angled. But if not, angled fins could enhance heat transfer if the flow was turbulent rather than laminar. But drag would go up if the improved heat transfer didn’t allow for a smaller radiator.

Of course the downstream airstream flow would also be of concern. So, it depends. Maybe somebody has test results.

[marcush.]

I have recently read about this and as far as I know there is currently no angling of the fins or tubes in the rads .

The long slanted radiators pose a lot of implications when it comes to the internal flow ....the ducting leading to the face of the core is very short and steeply curved at the top but very long at the bottom with a long staraight run up towwards an almost kink like transition to the radiator core.all in all this is less than ideal for the flow patterns through the core and I very much doubt this all is working very good -as can be seen on all those flowviz patterns we see in front of the sidepod entries ..they sort of ram the air into the duct and quite a bit of flow is going the wrong way at the entrance.
I wonder why nobody has ventured yet into graphite as radiator material ,even if it were just for the fins ...as graphite has very good heat conduction potential -it is already used in electronics and some outomotive applications as a heat spreader and for cooling fins ...maybe this is the next big step in f1 technology ...but what do I tell you ..it has been posted on some other thread already months ago.

As i understand the underhood flow is contributing up to 8% to the total drag of a road car these days ,obviously that´s not the case with a formula 1 car which has big wings and four open wheels ,but still there are gains to be found nontheless .Why else do all teams try to close or avoid openings in the sidepods as much as they can ....
The real gains are to be made by reducing the core size itself to shed crossection of the car ....the limit is here you cannot run the car much hotter as the boiling point of the cooling fluid is restricted by the mandatory pressure limit in the system .

[riff_raff]

How effective are the angled radiators in F1?
It looks as though the cooling fins are not in line with the flow of air, how big an issue would this be?

coaster,

If you think about it, the answer to your question should be obvious. While the term "effective" is fairly subjective, the liquid-to-air heat exchanger installations used in modern F1 cars are definitely highly optimized and efficient. The overall design of the heat exchanger installation is a compromise that must take into account many conflicting requirements. The trade-offs are installed drag, weight, air mass flow, duct inlet/outlet velocity, core pressure drop, etc.

As for the cooling fins, they are usually normal to the core face. Even if the core face is at an angle, the inlet duct typically does a good job of redirecting the incoming airflow. The typical F1 car uses a thin core with a large frontal area, and this requires the core to be installed at an angle in order to fit it within the sidepod. It would actually be possible to use a core with a very small frontal area and orient the core facing directly forward. But the core would also have to be very thick in order to achieve the required heat rejection rate.

[coaster]

Seems a bit off a grey area when aerodynamics are in question, but to be more exact my biggest concern is the cooling being compromised. I'm drawing up a trike based on various donor parts and looking to f1 for inspiration in terms of suspension (80's steel) and current clever packaging.
(putting the training wheels back on)

[marcush.]

there are some questions open in current sidepod design when it comes to cooling and ducting..why is there no bounadry layer separtion in the inlet design ?
what is the effect of having a very short inlet duct at the top and a very long duct on the buttom ? How much is the loss throu shear forces as there must be some resistance coming from the air hitting the radiator core .(the aiur will have to accelerate to enter the core as the effective crossection is partially blocked by fins and tubes,isn´t it?)
I feel the radiators look much too traditional and could benefit a lot by designing bespoke layouts using bigger spacing between the tubes and reducing drag simply by getting rid of the blockage.

[olefud]

there are some questions open in current sidepod design when it comes to cooling and ducting..why is there no bounadry layer separtion in the inlet design ?
what is the effect of having a very short inlet duct at the top and a very long duct on the buttom ? How much is the loss throu shear forces as there must be some resistance coming from the air hitting the radiator core .(the aiur will have to accelerate to enter the core as the effective crossection is partially blocked by fins and tubes,isn´t it?)
I feel the radiators look much too traditional and could benefit a lot by designing bespoke layouts using bigger spacing between the tubes and reducing drag simply by getting rid of the blockage.

I don’t disagree with your points. But there are two possible other factors that may be in the picture. With restricted free flow through the radiator, air may be “piling up” in the inlet and defeating separation. On the other hand, the inlet duct may be sized and formed to induce turbulent flow that would enhance heat transfer relative to laminar flow.

With the unlikely stuff they’re doing with aero otherwise, could happen.

[marcush.]

But :you would only want turbulence at the surface of the fins ,right? i don´t think there´s much to gain having a turbulent inlet situation at the entry of the duct...but I could be horribly wrong ...

[riff_raff]

The entire inlet/outlet duct and core flow and energy transfer must be considered. The inlet and outlet ducts are not only shaped to guide airflow, they also vary in cross section to adjust dynamic pressure and velocity. For example, you would obviously want higher air pressure ahead of the core than behind it, otherwise there would be no airflow in the desired direction. As for airflow turbulence, the core fins actually have tiny "turbulators" to tumble the boundary airflows over the core fins. We also need to remember that as the airflow passes through the core, it picks up energy and its velocity increases. Lastly, the outlet duct also varies in cross section such that the discharged flow converges and its velocity is greater than the passing airflow.

[bhall]

(Click each to enlarge)

I've always assumed that teams try to direct turbulent flow into the radiator inlets...to enable a measure of flexibility in terms of inlet size, shape and placement. In the photos above you can see how teams have placed various aerodynamic devices upstream to the inlets.

The white appendages between the upper and lower wishbones on the BMW appear to have sent an eddy to the radiators. The camera housings on each car seem to have been placed with similar intentions, and I think it's also the reason behind both the Ferrari's brake duct winglets and the front pull rod.

[...]

Does this make any sense as an efficient use of otherwise unrelated components upstream to the inlets?

[olefud]

It might, but riff-raff's "turbulators" would make more sense in that micro turbulance would be generated at the radiator.

[xpensive]

What you want is speed for optimized convection over a maximized surface with a minimum of aerodynamic resistance,
if you take a close look at the Red Bull radiator, there are not much fins a all, just long and wide profiled tubes.

Image anyone?

[marcush.]

errm thinking of it ,there is no way that Monza and Monaco will need the same radiator layout ...as the airflow -car speeds will be dramatically different ...you would not just assume a reduction in inlet or exit cross section will do it ,would you?

[xpensive]

Good point, depends a bit on how the radiator is sized I guess and if the water-flow can be thermostatically controlled?

Convection increases with the square of air speed, but fiddling with inlet areas from track to track seems a bit much,
or what do you reckon?

[marcush.]

there must be a optimum airflow vs heat transfer for a given core...so changing airspeed will inevitably pitch you out or inside the optimum window .
As the engine is producing the same power no matter how quick your average speed is ...you will need a bigger core ,more fluid circulating speed or a bigger duct to accomodate the slower road speed.