i am looking for some Senior Technical Guidance from a physicist and/or engineer and/or anybody that is knowledgeable about heat pipe design ... or has taken a hack-saw to a high quality heat pipe.
here's some examples ... these heat sinks use heat pipes as part of the thermal circuit from heat source to ambient air.
basically, the heat pipes for computer heat-sink-fan assemblies are usually used in a horizontal configuration (the part that is attached to the heat sink fins is horizontal, when the heat-sink-fan is used on a computer in a tower case.)
the "dogma" among computer enthusiasts is that "it doesn't matter too much", the orientation that is.
this puts some reliance on the "wick" inside the heat pipe, in order to get the thermal resistance down to a target .14 degrees C per watt.
thinking about it from the point of view of making my own heat pipes, it seems like the placement of a wicking geometry will make it more difficult for the fluid inside the heat pipe to circulate.
any references to technical papers or web pages that go into more detail on this subject would be most appreciated !
so far i found this. the reference to usage in satellites (no gravity, no horizontal or vertical) is interesting.
wwswimming at yahoo dot com
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i am writing to ask for your help making sure that i am using the heat-pipe technology correctly.
in my work as an engineer, when we used the term "heat pipe" it was always for any construction that acted as a conduit for heat energy, from the heat source, to a surface closer to the "cold-plate".
now, with PC's, like this
in each of those phase changes, from liquid to bubble and then from bubble to liquid, there is a latent heat of evaporation & condensation that is very effective in "moving heat".
OK but there's a big assumption in all of this - the ORIENTATION of the heat sink.
i haven't taken apart the heatsinks like the Zalman and the Thermal right and the Noctua. from the way they're pinched off, and from a lot of the posts about them, i get the conclusion that they are liquid filled and that the movement of the liquid inside the heatpipe genuinely helps heat transfer, whether or not the liquid turns into fizzy little bubbles in the process.
is the main part of this heat sink supposed to be vertical ?
this would mean that, when they are placed in a conventional tower workstation, the end of the heat pipe away from the CPU, is horizontal. so, how does the cooled-off fluid get returned to the CPU area of the heat pipe for another dose of heat ? if the heat pipe is horizontal, and it's a skinny heat pipe, it's not like pouring cold vodka into hot chocolate, in which case it mixes real quick.
so i'm wondering, since most of us computer folks are using tower cases of one kind or another, doesn't that leave these big beautiful heat sinks operating in a sub-optimal orientation, with horizontal heat pipes ?
have any of you experimented with your systems, like for example measuring CPU temperatures with the case mounted horizontally and vertically, to see if there's a difference ?
thanks for some good technical feedback. vodka-hot chocolate recipes are appreciated too. :D