Tom, I hear you, but I gotta side with tramway on this.  I read your story here, and 0 is damn cold, and being out servicing a truck on a night like that with a 40mph wind makes for a memorable night.  But, at 0 degrees, that fuel would be easily ready to gel, the whole tank of fuel would be cold and not getting heat from anywhere to counteract going down the highway.  Windchill makes it get cold much more quickly, but not colder. 

  I thought that wind chill thing is something that was on a physics test in high school.

I am with, you cannot get it colder than the ambient air temp, gang.

WIND CHILL ONLY EFFECTS THE FLESH.

SOURCE: THE INTERNET

 

Heat flows from warm to cold.  You as a living being trying to stay warm, technically feel the loss of heat rather than cold.  More wind removes the heat from you faster, and since your metabolism is trying to keep you warm, you feel colder.  But if you keel over dead, lay there and get cold, once you've reached the air temp, can't get any colder.

On things that generate heat, as in the human body or circulating warm fuel in a engine, wind chill can remove heat faster than the thing can generate it. 

On things with latent heat, as in a tractor that has been running and shut down, or a tractor parked in a warm shop and brought outside, wind chill can cause the thing to cool off faster that if their was no wind chill.

As has been said, wind chill will never cool anything down below ambient temp. Wind chill is basically a term meteorologist came up with to try and give a indication of how cold it feels to the human body. Even then, the wind chill will never cause your body to go below the ambient temp anyway, you'd be long dead before you ever got that cold.    

Some scientist argue that there is no such thing as cold, it is just the absence of heat. Everything would be at absolute zero (no heat in it) if we had no matter around us generating heat.  

Yep, agreed.

True.  Kind of splitting hairs to the meaning of windchill and what was meant in various statements, then again that's what usually happens in any discussion.  I wonder though, you have a tractor plugged in, block getting warm, may conduct to the fuel pump and filter some and start up.  But how long has it been how cold and therefore how cold is the fuel in the tank, and tractor starts right up but then even in the shed the cold fuel starts getting up there and it stalls anyway?  Never know for sure.

 

So, while we're on scientific stuff that's not productive, here's another one.

 

Did you know that there is nothing that measures temperature?  You said it exactly, it's a relative concept.  The 0th law of thermodynamics, to paraphrase, says that if 2 systems are in thermal equilibrium with a 3rd system, they're in equilibrium with each other.  In other words, you can only know by comparison.

 

Now if you're still laughing, thinking I'm an idiot, because you know lots of things that measure temperature, no you don't!  Think about it: Mercury (or other fluid thermometer) measures density, and as the fluid expands or contracts due to it's relative heat content, there's a calibrated scale showing degrees.  Clock spring thermometers measure the expansion of the metallic spring, calibrated to a temp scale.  Thermocouple measures the changing voltage output of a bimetallic junction, calibrated to read temperature.  RTD reacts to the change in resistance due to heat.  Every device reacts to some other phenomenon and is only calibrated to relate a temperature number.

https://www.zoro.com/power-service-products-diesel-supplement-and-cetane-booster-1080-06/i/G5573237/feature-product?gclid=Cj0KCQiA2vjuBRCqARIsAJL5a-Ja2OfUtfJZWohOQwRonze2uyuXEFCxcl0t8NSqoZDwdXptVD5bY5AaArY4EALw_wcB" rel="nofollow - https://www.zoro.com/power-service-products-diesel-supplement-and-cetane-booster-1080-06/i/G5573237/feature-product?gclid=Cj0KCQiA2vjuBRCqARIsAJL5a-Ja2OfUtfJZWohOQwRoNze2uyuXEFCxcl0t8NSqoZDwdXptVD5bY5AaArY4EALw_wcB

I think it's safe to say, at -460F, diesel would gel, regardless of wind!

re:

It’s kind of like the speed of light, it’s theoretically possible, but impossible to obtain in practice.

Well, theoretically (according to scientists....) Bumbelbees cannot fly....

as far as going FTSOL, it is possible, you just have to rethink what it is....

Thanks DMILLER, The guys that claim windchill effects "nothing" have somewhat lost my credibility in their statements. I have personally seen 2 vehicles- same engine/same mileage/same year vintage, have 1 of them fail to start due to a dead battery stored "outside" in the wind vrs the unit parked under a lean-to and OUT of the wind.

 

Now I admit, I'm not all that smart, and don't understand a lot of it, but I've done some studying up of the speed of light. The way I understand it, when you get up to hypersonic speeds, the energy required to keep gaining momentum compounds rapidly (even in a vacuum with no friction). According to scientist, by the time you get close to the speed of light, the energy required to gain any momentum becomes infinite. I don't understand hardly any of this, but of course 75 or so years ago scientist said it was impossible to go faster than the speed of sound. 

 

Just more worthless info that has noting to do with the original topic.

And do you know what the specific gravity of the two batteries were? That in of itself could make all the difference in the world. Wind chill will have no effect on inanimate objects, other then it will cause them to reach ambient air temperature quicker. 

I find this stuff fascinating, wish I was smart enough to have worked in theoretical physics.

Happy Thanksgiving, all!!!  Seein's that today's holiday is a celebration feast, I find it appropriate to perform today's virtual demonstration using common Thanksgiving-day format:

Gelling occurs because fuels have additives which rather than being dissolved, are in suspension.  Sitting at our family dinner table, I will use what I have at my immediate disposal, and give you the old-time-radio-show:

Watch, as I take my sister's glass of water, and add various substances... Note that I can stir in, and dissolve this sugar in water... now I can add some salt... it too, will dissolve... but notice that when I add pepper, it does not dissolve- it simply floats on top.  If you pour pepper in salt, it will tend to float to the top. Now watch, as I add more salt... the pepper starts to spread away from the edges... that's because the salt has attached to the pepper a bit, and changed it's character as a compound.  Now drop in a little spot of butter.

Of course, the butter just floats on the water, but now I'm going to hold this glass over one of the candles... and notice, the butter melts... spreads across the top of the water, and if I add more salt... and more salt, and more salt, the butter vanishes from the top, and the pepper now appears to 'mix' in with the hot water. 

This is called Emulsification.  The combination of materials which, when proper circumstances exist, promote even suspension of normally non-solubles into a solution.

This happens in EVERYTHING... from my sister's water glass, to your diesel tank, to your car's fuel tank, to the glass of wine at your dinner table.  There's stuff in there that doesn't mix.

Now, I've placed Kathryn's water glass on the table to cool for 15 minutes, and notice- there's butter floating on top, with pepper globs in it, and below... the inside of the glass is starting to turn white...  the butter has coagulated out, with pepper stuck to it, and salt is precipitating out and binding to the inside of the glass.

All aspects of Solution is TEMPERATURE DEPENDANT... that includes Emulsification and Precipitation.

Diesel fuel contains Paraffins to help keep all the additives and fractions in suspension. 

Realize that Diesel Fuel is a generic term used in compression-ignition engines, the PETROLEUM component is HYDROCARBON (HC)... primarily Cetane, but other ANEs... and then there's additives.  Bio fuels are predominantly CARBOHYDRATEs... they end on OL, rather than ANE.  Carbohydrates and Hydrocarbons cannot be mixed to yield a stable solution.  In the case of diesel fuel, they must have PARAFFIN added, in order for them, and lots of ancillary additives, to be properly suspended.

Paraffins WILL thin and dissolve... as long as the solvent and temperature are appropriate.  I use a centuries-old mix of beeswax, turpentine, and linseed oil to make wood and metal protectant... and as long as it's warm, it will be a nice liquid... but the turpentine evaporates out quickly, and once cooled, it turns into a soft paste.  If I dip a freshly-machined part into the liquid, as soon as I withdraw the part, the wax-mix coagulates to form an airtight protective coating that will prevent the part from corroding.  When I make a high-precision air-bearing, I dip it in wax mix, then carefully package it for shipment... and 200-year-old technology gets it to the far end with 100% protection.

Diesel fuel...  like my wax mix... and my sister's (now undrinkable water glass) is a liquid state at a certain temperature.

My wife, as a summer job (she's a schoolteacher) worked as the lab technician at a local fuel terminal.  Every Wednesday, she took a styrofoam cooler, and made a trip to Whitey's Ice Cream to get milkshakes.  They placed a half-pound bag of dry ice in the bottom of the cooler, and placed milkshakes on them, and she drove 4 miles down to the terminal.  She then used the dry ice to perform tests on the fuels, and used the ice-cream to verify proper function of everyone's taste buds.

Each fuel type consisted of 5 samples, they chilled and heated each, determined the property changes, evaporation points, vapor pressures, and finally, put them all back to 68F, and placed them in a centrifuge at 2500G to see how they'd settle out.

The point at which gelling occurs, is NOT a fixed point... it depends on many factors, but if you do your own testing, you'll find that regardless of GRADE of diesel fuel, you will start to observe paraffins coagulating around 30F.

IF little droplets of WATER in your fuel comes in contact with a surface below 32F, it will freeze into little solid droplets... and being a crystalline structure, it will expand to a greater volume than it did as water... with an expansive force of 115,000psi.

(irrelevant to this lesson, but interesting note-  if you have a family heirloom locked inside a safe which you no longer have the ability to open by proper means, take it outside, drill small holes around the hinges and lock, and fill them with water, let them freeze overnight... and the safe will be open tomorrow.  Water expands with higher force than most steels of same volume can withstand)

Back to fuels... so your diesel is cooling, and turning to waxy goo... at least, in the area near the containment most exposed to low temperatures.  This means, on a 28F morning, the fuel in the MIDDLE of the tank might still be at 40F, the fuel against the walls of the tank is at 34, and that which is in the fuel LINE is at 28.

Start the engine, and let it idle.  Fuel from tank, is drawn up the line... but fuel in the line and the filter is already waxy.  The wax is drawn towards the filter, which starts to plug up.

As part of their normal operation, Diesel injectors BYPASS unused fuel back to the tank.  The bypassed fuel helps cool the injector tip, which warms cold diesel nicely.  That return fuel helps warm the tank, but not darned much, and it's travelling down 20 feet of steel fuel line that's directly exposed to the wind, so by the time it gets back to the tank, mebbie it's 31F.... JUST warm enough to dislodge chunks of wax from the fuel tank and send 'em up the plumbing to the filter.

At this point, the 'temperature' of gellation, and the 'temperature' outside, and the 'wind chill' all become moot:  The process has begun, and your engine will be starved for fuel before you ever get to throttle it up.

You can add more solvents to your fuel to prevent the emulsifiers from coagulating... how WELL it will work, depends on many factors, but first and foremost, if your fuel filter is full of wax, you could pour ANYTHING in that fuel tank, and you'll still have a filter full of wax.

Why is #1 diesel less subject to this? because it is a simpler mix... it contains more controlled list of petroleum fractions, and requires less additives and emulsifiers to yield a viable fuel... and it's performance over temperature change is much, much more predictable.  It just costs more.

Part of preventing gell/freeze is about having good fuel and clean filters, but just as much of it is design.  A fuel system which is designed to flow well when gelled (big filters, large fuel lines) and stay warm (protected from elements, with fuel heating loops from exhaust, oil, or coolant heaters), will perform best in winter.

Lars, when I was down in Kermit, and up in Hobbs last summer, ANY temperature was a good temperature to serve beer, because the beer was always cooler than OUTSIDE.

I stayed in the 'man camp' in Kermit, and was really impressed with the lodging, the  staff, the food, and the services...

... but they only had Root Beer...