That will warm the beer nicely.
Spot the fault...
- Thread starter RF Lighting
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Quite often find with thermal imaging that where a tail is bent, it runs warmer than where it is straight. Someone with some physics can explain it!
You can also notice it with shower cables. A shower cable clipped up inside an airing cupboard runs cooler on the straight runs than it does at the bends. Noticeable to the hand.
You can also notice it with shower cables. A shower cable clipped up inside an airing cupboard runs cooler on the straight runs than it does at the bends. Noticeable to the hand.
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Lec, you don't need physics to explain it.
Where the cable's bent, the electrons have to slow down to go round the corner.
Thus, they form a queue, jostling and bumping into each other. This is why the cable heats up on bends.
Where the cable's bent, the electrons have to slow down to go round the corner.
Thus, they form a queue, jostling and bumping into each other. This is why the cable heats up on bends.
I presume that at least one of the mechanisms is that any bend, particularly a tight one, has the capacity to produce localised reductions in effective CSA.
However (never thought of this before!), 'trying to be clever' and thinking of the physics (particularly Newton's laws), does not some energy have to be expended in order to persuade an electron (which has mass) to do something other than travel at constant speed in a straight line? Mind you, considerations of quantum physics probably screw that all up!
Kind Regards, John
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As I think you know, electrons in a conductor don't travel at constant speed in a straight line, they just jump to the next atom.
However, I think the reason for the higher temperature is simply the localised increase in ambient temperature reducing the ability of the cable to convect heat.
back to the original question - I can see the serious fault. The focus function of the camera has failed!
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It's not focusing on the beer?
Perhaps it's not focusing because of the beer!
Yes, that's true. As I said, I was just trying (clearly not hard enough!) to think of a way of 'being clever'
Maybe, but there are two sides to any bend, and the opportunity for convection loss might increase on one side when it decreases on the other - but that, too, is probably 'trying to be too clever'!
Kind Regards, John
I'd expect the ambient temperature to be about equal either side of the bend, hence convection loss will be the same.
Now for radiated heat loss you have a point.
Now for radiated heat loss you have a point.
Won't the convection (as well as radiation) loss also be different (even with the same ambient temp on both sides of bend) because of the different surface area? Increasing the size of a CH 'radiator' will result in more heat 'loss' by both radiation and convection, won't it?
Kind Regards, John
But if you consider say a 12" length of cable, the surface area hasn't increased if it is bent.
We're not increasing the size of the CH radiator, we're bending it, and I'd expect the temperature inside the bend to be greater than that on the outside.
RF, give us some more clues!
We're not increasing the size of the CH radiator, we're bending it, and I'd expect the temperature inside the bend to be greater than that on the outside.
RF, give us some more clues!
Not necessarily changed overall, but the surface area on the outside of the bend will surely have to have increased and/or that on the inside of the bend decreased - is that not the nature of bends?
Indeed - and, ideally (probably not possible!) a better photo!
Kind Regards, John
Does this help?
Just a wild guess but are the cables 'tucked' around the swa and therefore having more current induced into them?
Indeed.
IANASAP, but I'm pretty sure it would be quantum mechanics, rather than Newtonian, which would be involved.
At the scale of a cable, electrons don't move in straight lines, and actually drift at a very low speed.
Try to keep up BAS!
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