| Author |
Message |
    
Fast1075
| | Posted on Friday, July 06, 2012 - 08:07 am: | 
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Actually on the subject of "coolant" (ethylene or propylene glycol), the higher the mix ratio, the lower the rate of heat exchange.
I "fix" chillers all the time that "don't work" (insufficient capacity) by resolving the overly high glycol mixtures.
In a previous job, we had detroit diesel engines "cook" without ever reading high coolant temps on the data recorders or ever tripping a murphy gauge. The detroit factory guys determined that the problem was caused by using too high a glycol mixture. After we changed the mix ratio, the problem went away.
The only real functions the "coolant" serves are to prevent freezing, inhibit corrosion, and act as a lubricant.
The lower the ratio, the better as long as you have sufficient antifreeze protection and anti-corrosion protection.
The water in the mixture will still boil at 212 degrees F if it is not under pressure. |
Bbird
| | Posted on Friday, July 06, 2012 - 11:17 am: |
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Has anyone tried the EARTHX brand? I saw them on EBAY. |
Stirz007
| | Posted on Friday, July 06, 2012 - 11:56 am: |
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"Yesterday. Or three years ago. Your choice."
Except none of that stuff is track legal.
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Aesquire
| | Posted on Sunday, July 08, 2012 - 08:15 am: |
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Fast, what do you mean by high mixes?
Straight glycol is indeed not as good a heat carrier as a 50/50 mix. The 70/30 mix is for subzero antifreeze performance. ( where the heat transfer is aided by low air temps )
It strikes me as funny that a company would use straight glycol based coolant without properly mixing it.... spending more money for worse performance. ( not funny-ha ha, funny, "snort..idiots!" )
http://en.wikipedia.org/wiki/Antifreeze
The glycol based coolants were developed back in the 1920's and the reduction in radiator size that permitted let airplane designers greatly reduce cooling drag.
Compare the earlier P1 with the later P6E.
http://en.wikipedia.org/wiki/File:Curtiss_P-1B_Haw k.jpg
http://en.wikipedia.org/wiki/File:Curtiss_P-6E_Haw k_071107-F-1234S-004.jpg |
Kenm123t
| | Posted on Sunday, July 08, 2012 - 09:31 am: |
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glycol was an accident its the waste product of making plastic from natural gas
Union Carbide was dumping it in the Kanawha river and some one noted the river didnt freeze when they did.
pure water has a specific heat of 1
as Fast / Harry stated we have to account for the Decrease in heat exhange with glycol mixes in chillers. The in aircraft before glycol they used alcohol if you raised operating temp in the radiator too high it vaporizes out of solution See home brew 101
Glycol vaporizes at a higher temp and has a much lower temp capability.
Operational range on aircraft engines is huge do to temp lapse rate along with turbos and or lean operation at altitude. |
Aesquire
| | Posted on Monday, July 09, 2012 - 09:09 pm: |
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Don't forget lower air pressure. ( lower boiling point ) a proper mix, under pressure was a big help to airplane cooling issues... Cooling Drag being the other factor. Unpressurized water radiators are much bigger than pressurized glycol/water radiators, with much more cooling drag.
The 20's racers hung watermelon sized radiators out on struts, or covered the wings with copper tube & sheet radiators ( Huge drag difference, major maintenance problems ) finally making good looking ( if not good working ) scoops and ductwork.
Not until the P-51 Mustang did they get a breakthrough in cooling drag as big as the switch to pressurized Prestone radiators, and that was by careful duct work ( and wind tunnel testing ) that used the expanding, radiator heated air as jet thrust to counter most of the drag of the radiator. ( the "Meredith Effect". Despite the wiki article, the Spitfire got little advantage from the effect. ) |
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