Engine Cooling Water Tank Sizing

[John Noonan]

perhaps Dean can supply some info..

J

Thanks Dean..

Also thanks to the other folks as well.

John

[Harold Bettes]

Wow, I didn't realize that I was lighting a brush fire!

Please consider the following points for sensible design goals on a cooling system for Bonneville:

The boiling point of water at Bonneville will be about 200F (at atmospheric pressure there). The system (unpressureized) proposed was a volume of water, so the temp of the reservoir at the end of a run should be less than 200F (probable target about 175-190F). That is why I listed the formula for a reservoir.

The flow of water across the heat generator (engine) should be in general much more than those little water puppy type units. The water flow carries away heat from the backside of the combustion chamber and the exhaust valves so that the chamber is less prone to encourage incipient detonation. That is why I listed the simple formula for water flow in gallons per minute (GPM). It is a pretty good rule of bruised thumb to use at least 10GPM/100Hp for heat dissipation.

It was well stated when it was said that there is much more to an accurate study of the thermodynamics of a water system, but I wanted to try and make it both understandable and usable without complex mathematics.

As to the question by the Cajun Kid: One would need a pump supplying about 106GPM with a reservoir of about 38 gallons (316lbs) to dissipate the heat from a 600Hp engine that would increase the temp from 100F to 180F in about 3minutes. That considers no cooling other than the mass of the water and with atmospheric pressure on the reservoir. Things change appreciably when pressurizing the system and dissipation of some of the heat to atmosphere via forced or natural convection.

Hope that hasn't muddied up the cooling water issue too much.  It makes one appreciate how much heat a radiator actually dissipates in the cooling system and how nice the additional airflow across the radiator works at speed a;beit with some considerable drag involved.

Regards to All,
HB2

[SPARKY]

I for got 2 things:

1.  aways use distilled NON MINERALIZED water---you do not want the minerals forming ceramics or deposits in you block and heads.

2. in my opinion you need the PRESSURE from a mechanical water pump---step it down where it doesn't turnnover 5500 at max rpm---my Alt and water pump are geared to turn 5200 at 8000. 

Thanks to Mr. Mack, Mr. Jones, and Stewart water pumps for the education and desigh help.

I will be adding a feature this year thanks to Dave D.: I will be runing water that normaly would be going to the heater in a car through my dry sump tank to help in heating the oil at warm up and cooling the eng. at WOT.---trying to get the systems ready for:

 ARTIFICAL Density Altitude---Tom B's term---lol

[sockjohn]

Specific Heat Capacity
Specific Heat Capacity is the amount of heat a particular substance can hold.
Water   4.18

3M Flourinert FC-43   1.47

Fluorinert $770 for ¾ gallon. Nuff said.

At a previous job we used to buy the 3M Flourinert by the gallon jug.  There are different versions with different temperature ranges, and I wondered at the time if it couldn't be useful to make engine cooling in two tanks, one that is heat soaked to keep the engine at operating temp, and a second containing really cold Flourinert and a flat plate heat exchanger.  Would require two water pumps, but that would be a plus as you could keep the engine water at constant  temperature by controlling the water pump to the heat exchanger.

You can't go lower than 32 on the ice bath, but with the Flourinert you could go colder than you could achieve with dry ice.  Liquid nitrogen would be to cold unless carefully applied. Lower specific heat capacity only matters if you can't go really cold.

Dean's comment about Nuff said says it all for my budget though! 

I guess the idea of two tanks would still be valid, but more plumbing and more stuff to go wrong.

[saltfever]

Thanks to Harold and others.  Like Rex said “good information”.  
I would like to reinforce what Harold said because it was not part of his formula and was a byline whose importance may be missed.  2/3 of the heat goes out the exhaust pipe! You don’t need to build in cooling capacity for it. You only need to cool 1/3 of crank HP. So consider using 0.3HP in his formula. When boosting with a turbo remember; most of the heat is used to drive the turbine and then is exhausted. You don’t need to add 100% of the added boost HP. Don't minimize what Rex said. The phase change from a liquid to a gas (i.e., making steam) is endothermic. It requires a tremendous amount of additional heat and is sometimes quite useful as Rex indicated.

[donpearsall]

Hey Saltfever, that is a good point about the heat out of the exhaust. I imagine there are other heat dissipation factors too, like radiation of the block.
Thanks to everyone who is contributing to this. I am learning a lot.
Don

[donpearsall]

Harold, I am not understanding how you got the solutions to Cajun Kid's parameters.

Horsepower - 600
Delta Temp - 80

You said his GPM should be 106, however using the formula given was GPM = (C x HP) / delta T (or GPM = (1*600)/80 in this case), the GPM is 7.5

Please explain. Should I go back to 7th grade?

Don

[LittleLiner]

Harold what does the subscript h20 stand for in the time formula? (M_h20)

H₂O is Water

[Harold Bettes]

Please note that the portion of engine power at the flywheel that is considered a cooling system load is approximately 1/3 or .33 x Hp at flywheel. Then it must be converted to BTUs. 42.44BTU/min = 1 Hp.

So, 600 / 3 = 200. 200 x 42.44 = 8488. 8488 / 80 = 106.1GPM

Listed previously is correct that M_h2o is Mass in pounds of water.

Hope that helps stuff be more clear.

Yeah, I know that many folks are getting by with less water flow and less volume, but I would often be at odds with the way that things are commonly done.

When you calculate something based on many assumptions, you are apt to get varied results. Such as how long will you be needing to dissipate 1/3 of the power to the cooling system and other variables. Hopefully this stuff will help and not hinder your efforts on the salt.

Regards to All,
HB2

[donpearsall]

OK, thanks. I did not realize that the HP should be in BTU in GPM formula.

Don

[Geo]

Don, thanks for the question.

Harold, Thanks for the answer walk through.

Everyone, thanks for the info share.

Geo   javascript:void(0);

[rebelce]

Just to elaborate on a single point.  In WWll,  The Heinkel 100 used an evaporative cooling system and completely did away with radiators, using the wings instead. The thing went 394.6 MPH in 1938.

http://en.wikipedia.org/wiki/Heinkel_He_100

[floydjer]

Just to elaborate on a single point.  In WWll,  The Heinkel 100 used an evaporative cooling system and completely did away with radiators, using the wings instead. The thing went 394.6 MPH in 1938.

http://en.wikipedia.org/wiki/Heinkel_He_100

Interesting read.......EXPLOSIVE RIVETS? !!!! Had to google that one. Jerry

[manta22]

"EXPLOSIVE RIVETS? !!!! Had to google that one. Jerry"

Jerry;

Expolsive rivets weren't that uncommon in the US aircraft industry years ago-- you could even find them on the surplus market until a few years ago. They were an adaptation of the standard solid aluminum rivet except that the end of the shank was hollow and filled with a mild explosive compound. To set them they were inserted into a hole and then a heater looking like a big soldering iron was placed on the head and the heat detonated the explosive, flaring out the rivet and setting it in the hole.

These were used in "blind" applications (there was no access to the backside) where a rivet could be bucked. The development of modern blind rivets and pulling tools made explosive rivets obsolete.

Regards, Neil  Tucson, AZ

[Ron Gibson]

The memory goes when you get old but IIRC GM used some explosive rivets on the grills of some models. You had to go to the dealer for them if you needed to change the part. Keep in mind I have been wrong before. LOL

Ron Gibson, Omaha NE