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Fuels & Lubricants Discussion all about Fuels & Lubricants. synthetic oil, conventional oil, brands, change intervals, diesel grades, gelling and such debated items like that. Non TDI related postings will be moved or removed. This forum is NOT for the discussion of biodiesel and other alternative fuels.

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Old November 22nd, 2000, 07:57   #31
davidr
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Default Re: Windchill, does it effect the gelling of fuel?

This is why I joined this forum.

You guys make me laugh.

thanx,

david
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Old November 22nd, 2000, 09:36   #32
SkyPup
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Default Re: Windchill, does it effect the gelling of fuel?

time to "chill out", even here in Florida it was 21*F this AM, thank God for the Vermont Castings Woodstove!
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Old November 22nd, 2000, 09:45   #33
jorpet
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Join Date: Oct 2000
Location: West Seattle, WA
Fuel Economy: 48 Lifetime
Default Re: Windchill, does it effect the gelling of fuel?

Funny thing about water temperature, ambient temperature and wind. I played with a swamp cooler in Denver when we were there and found the following:

Outside Temp = 90
Starting H2O temp = 90

Start the pump, wait an hour,
Outside Temp = 90
H2O temp = 85

Start the Fan (pump still running), wait an hour
Outside Temp = 90
H2O temp = 45 degrees

Quick, someone tell me why! and don't talk about evaporative cooling blah, blah, blah, because there was a post up above that said that the water temperature would not be affected by wind!!! In that case whether the fan runs or not can't have any effect what so ever!

Was someone sneaking in and putting ice cubes in the water? They must have been!!

I do realize this is only emperical data and may only apply to real life applications .

[This message has been edited by jorpet (edited November 22, 2000).]
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Old November 22nd, 2000, 10:26   #34
shirish_bh
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Default Re: Windchill, does it effect the gelling of fuel?

Just another comment about windchill.

I guess wind chill takes into account the overall heat transfer co-efficient between the human body (97 F) and the ambient air.
Higher the wind velocity, higher is the wind chill.
So a wind at
5 mph and 32 F ambient temp
may feel like wind at
0 mph and 28F. (I am just making numbers up).

So,
Actual temp = 32 F
Wind chill = 28F.

Living things (warm blooded animals) will feel the wind chill because their body temperature will never reach ambient (it better not!).
The temperature of inanimate objects like cars (I apologize) will reach ambient, so they do not feel the wind chill.

Hope this helps.



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Old November 22nd, 2000, 19:33   #35
mickey
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Default Re: Windchill, does it effect the gelling of fuel?

If you want to know about the swamp cooler thing I'm afraid I'll have to talk about evaporative cooling. Sorry.

With the pump running, but no fan, the water was evaporating slowly. With the fan running the water was evaporating quickly. The more rapid the evaporation, the more cooling effect. (You also need to consider that more rapid evaporation from the tank resulted in more rapid replentishment of the the water with COLD TAP WATER. But my point is still valid. You really want a swamp cooler to work well? Spray the pads with a constant stream of cold water from a hose!)

The definition of "wind chill factor" refers to how cold the air FEELS, not how cold it actually is.

All other things being equal a car's engine will cool off more quickly on a windy night than on a still night. The warm engine heats the surrounding air, and that warm air itself is an insulating layer that slows further heat loss. If cold air is circulating and blowing the warm air away the engine will lose heat more rapidly. This is also the primary reason for the "wind chill" phenomenon since evaporation of moisture from your skin is only a small part of the equation, but by definition "wind chill factor" has to do with how a person FEELS. Cars can't "feel" anything. If the ambient air temperature is 20 degrees the engine will reach that temperature more quickly on a windy night, but it won't drop below the ambient temperautre whether the wind is blowing or not.

-mickey

p.s. I can't believe I just posted that. What a silly discussion!

p.p.s. And to answer the original question (again): If the ambient temperature is below the gel point of the fuel then the fuel will drop to the gel point on a windy night more quickly than on a still night. Call it "wind chill" if it makes you feel better but it has nothing to do with evaporation, or how the fuel "feels." It has to do with the layer of warmer air surround the tank, lines and engine being blown away by the wind and replaced with colder air, which absorbs heat more readily.

[This message has been edited by mickey (edited November 22, 2000).]
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Old November 22nd, 2000, 19:53   #36
RabbitGTI
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Default Re: Windchill, does it effect the gelling of fuel?

This thing won't die. The original windchill derived in 1945 is an approximation of the cooling power of the atmosphere. The variables are air temp and air velocity. The derived quantity is a cooling RATE. That equation applies to people, cars, rocks, snakes, water, anything with an initial temperature higher than the ambient air temperature. Mickey summed up the original question: if your gelpoint is above the ambient air temp and you park in the wind, the windchill will make sure you're screwed a little quicker than you would be in still air. As far as the tweaked version of that first equation that applies to people, the "feel" is actually a quantifiable cooling rate. If it's 20F outside and the windchill is -10f all it means is you will lose heat standing in the wind at a rate equivalent to standing in still -10F air. You'd be amazed how many people think the weatherguy saying the windchill is -35F means it's -35F outside.
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Old November 23rd, 2000, 07:31   #37
lrpavlo
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Default Re: Windchill, does it effect the gelling of fuel?

Just gotta know!!!!
Isn't it true that Diesel fuel came from a once living organism? ( Kinda like Ric's apple pie??) So how do we know diesel fuel or the other parts of the car derived from petroleum products don't FEEL the effects of windchill????
I sure hope we are all LOL, Happy Thanksgiving!

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Old November 23rd, 2000, 11:29   #38
SkyPup
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Default Re: Windchill, does it effect the gelling of fuel?

My TDI has feelings, it purrs like a tiger when I fed it Amoco Premier with or without cetane boost! lol

lol to all! have a good one.
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Old November 25th, 2000, 05:30   #39
dsljay
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Default Re: Windchill, does it effect the gelling of fuel?

I KNOW that windchill referes to how cold it feels on flesh,BUT; I also know from experence that trucks parked on the west side of our unheated terminal,out of the wind,start easier and are less likely to be frozen-up then the trucks we park on the south side of the terminal, in the wind. Also,I know that running trucks parked in the wind will gel faster then a trucked out of the wind.This isn't book learning, it is 35years of driving trucks.

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Old November 25th, 2000, 07:06   #40
Mthiker
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Default Re: Windchill, does it effect the gelling of fuel?

dsljay: when I was stationed in Alaska we had to watch where we parked our trucks for the same reasons you pointed out. But still the truck would not cool any farther down then the ambient temp.

There is a condition in weather called super cooling where rain drops do in fact cool to a temp below 32F, as low -20F, and will not freeze. This happen where the heat in the water is dissipated at a very high rate. This is some what how the swamp coolers of the southwest work. The air blowing through the water curtain dissipated the heats in the air thus heating the water thus cooling the air below the ambient air. The colder the water, the more heat it can take, the cooler the air.

Don't get super cooling confused with wind chill. Diesel fuel with not cool below ambient temp. Fuel in our fuel is not being super cooled, no mater how strong the wind is.



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Old November 25th, 2000, 09:42   #41
SkyPup
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Default Re: Windchill, does it effect the gelling of fuel?

Winchill cools skulls with brains in them to the point of gelling, NOT diesel fuel tanks!
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Old November 25th, 2000, 14:07   #42
msauve
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Default Re: Windchill, does it effect the gelling of fuel?

Things can and do cool off to a temperature below ambient.

It is a condition well known to astronomers - point your telescope at that black sky, which has an temperature in the low Kelvins, and your lens/mirror will eventually condense dew, because of radiative heat loss to the sky. Radiative heat loss can result in object temperatures significantly less than ambient (air) temperatures.

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