Engine cooling numbers?

[xpensive]

This is getting interesting, I guess there's a point in not having too high a temerature diff agross the engine either,
never though about that, but it makes a lot of sense unless you believe you can constrain thermal xpansion somehow?

Anyway, at 500 liters per minute and a back-pressure of 5 bar, that water-pump will have an output of 4.2 kW,
or an 8 Hp input at a 70% efficiency.

[747heavy]

someone fancy to do a matlab model?

http://www.gtisoft.com/archive/confarch ... System.pdf


this is maybe a good read for the problem at hand:

http://www.roush.com/LinkClick.aspx?fil ... 12&mid=932

[747heavy]

as a picture tells a 1000nd words, here some graphs from the GT40 paper:

Enjoy









and from another source:


according to this ~30% of the energy content of the fuel go into the cooling system
(water and oil)

[Belatti]

Wow! engine to radiator coolant diff pressure seems high compared to radiator/intercooler. Is that the price to pay for having frontal radiator in a mid engined car? Or another effect of keeping small pipe diameters in order to save weight?

[747heavy]

I think the number is so high, because this specific car uses a water/oil heat exchange to cool the engine oil.
I would think, that the pressure change across the heat-exchanger is included in the "Engine to Radiator" number.

The change in the "Radiator to Pump" number gives an indication of the "plumbing losses" due to the mid-engine front-radiator installation.

IMHO - but I could be wrong

[ringo]

heat exchanger calculation of the radiator?
Need to know how many tubes and their cross section and length.
Also need to consider air temperature and flow rate.

Toyota should have specified at what speed they achieved that temp difference. May as well be on the engine dyno with a little dyson fan.

I think we can do a little calculation; a simple one at steady state.

[xpensive]

I think the number is so high, because this specific car uses a water/oil heat exchange to cool the engine oil.
I would think, that the pressure change across the heat-exchanger is included in the "Engine to Radiator" number.

The change in the "Radiator to Pump" number gives an indication of the "plumbing losses" due to the mid-engine front-radiator installation.

IMHO - but I could be wrong

Should I interpret the diagram above that the total loss for the entire water-circuit is some 70 psi? If so, my guesstimate
of 5 Bar (72.5 psi) was one helluva lucky shot, and the 8 Hp loss to the 500 Lpm waterpump not a bad call at all?

[747heavy]

I think, you should exclude the intercooler number.
Anyway, it would only bring it down to ~65 psi - so your estimate is still pretty good.
I´m sure a F1 radiator installation is a little bit better, due to shorter pipe length/better routing, but the power "loss" from the engine just to drive the oil & water pump as well as the alternator is perceptable and very real.

One of the reasons, that modern road cars, incoperate variable flow oil and water pumps to save energy/fuel, and not using your water pump as an "engine braking device", if you don´t need max. flow rate.

[747heavy]

not 100% related to the thread topic, but maybe interesting for some of you.

[xpensive]

Still, my gutfeel tells me that within F1 you would not settle for a 500 lpm flow, costing 8 Hp or more of pump losses,
with a delta T of just 6 to 8 K or something.

Not to speak of the aerodynamic losses thru a core like that, hitting from an angle, it looks like a brick wall basically?

[marcush.]

as I understand the cooler core matrix is not that special in F1 so the delta t will not be significantly better .So you need the waterflow and you need the air flow to get the heat out of the system.

[747heavy]

would be / is the limiting factor not the "heat release rate" between the water and the air?

If you could, you would want a higher delta T, but if it is correct that you have to use water(+antifreeze), and with the max. pressure limited, this is limiting the max. water temp. possible
Otherwise they would maybe try to run the engine hoter.

[ringo]

not 100% related to the thread topic, but maybe interesting for some of you.

I think i've seen redbull and williams with a curved radiator as well.
They probably eek out more area that way.

[ESPImperium]

not 100% related to the thread topic, but maybe interesting for some of you.

[img]http://www-static.shell.com/static/moto ... 01.jpg[img]

I think i've seen redbull and williams with a curved radiator as well.
They probably eek out more area that way.

I think your right there, the RB5 had a skewed radiator but was a rumored 0.2 litres a second off optimum, and with a curved one id recon you could just eek out enough to make cooling less of an option. Williams did have one on the FW31 for the Toyota power plant but that radiator wasnt compatible with the Cosworth one so i think they dont have one any more.

However, i think Mercedes and Mclaren now have one as well. This could just be to get their numbers needed but with a smaller radiator, thus reducing weight and making the cars have a even more waisted apperance, this having an aerodynamic impact.

I recon that cooling has become the massive black war in the post appendage ban of the 2008 regs and the post refuling ban from the 2009 regs. The team that can cool their cars with the least ammount of fuss and reduce drag whilst keeping downforce the same will ultimatly have an advantage. One other advantage will be the ammount of fuel they carry at the start of the race will be less, another thing it will also do is make their cars manage their tires better, maybes get an extra lap out of them when they are on the edge of being done.

I can see cooling being the new dark war for the future.

[xpensive]

I see two parameters of importance in this war of details ESP; Limiting losses through the radiator, water-flow resistance minimizing pump losses, some 5-10 Hp there, but perhaps more importantly, air-flow resistance through the passage.

Imagine duct openings being 0.1 square meter, air-speed of 90 m/s (324 km/h) and a total Cv through the passage of 0.5,
gentlemen, that's 22 kW or 30 Hp!