Pro/Forums - View Single Post - Metallurgist? Copper annealing discussion.

myv65 · 04-25-2003, 08:10 PM

@bigben,

Ben, you often seem like a programmer that's trying to create a massive program but has only a list of programming terms to use and none of the understanding of what those terms actually do. You're able to type in the terms, but don't seem to understand the syntax. Bill's point here is that the "C/W" of a block is more than simple conductivity. In the loosest sense, C/W implies a temperature change based on heat load. In the specific case of Bill's testing and waterblocks, it means the temperature between the base of the block and the water flowing through it.

This means that a block's C/W is really two-fold (ignoring minor stuff like convection to air off its surface and virtually zero radiation energy exchange). The first part is conduction of the heat through the block structure. The second part is the convective resistance getting that heat into the water. This second part is purely a surface phenomenon and other than how the heat is distributed over the surface, conductivity has nothing to do with it.

This is why dropping a block's conductivity by 10% via cold-working is not so bad. Conduction through the block is probably (just an off-the-cuff guess here) about 50% (ideal would be 50%) of the C/W of a block. So improving conductivity by 10% would mean a delta-T reduction of about 5% of the delta-T that occurs from block base to fluid.

A change of this magnitude is piss in the wind when compared to the variation that Bill gets from one block mounting to the next. The only way this is measurable is a test geared specifically toward a measurement of conductivity, which not even Bill's fancy get-up could manage.

I'm all for folks exploring the unknown and seeing what's possible, but I prefer to be realistic about the potential benefit. The potential of this one is not so big, especially when compared against using "good" copper versus a lower conductivity alloy or aluminum.

04-25-2003, 08:10 PM	#72
myv65 Cooling Savant Join Date: May 2002 Location: home Posts: 365	@bigben, Ben, you often seem like a programmer that's trying to create a massive program but has only a list of programming terms to use and none of the understanding of what those terms actually do. You're able to type in the terms, but don't seem to understand the syntax. Bill's point here is that the "C/W" of a block is more than simple conductivity. In the loosest sense, C/W implies a temperature change based on heat load. In the specific case of Bill's testing and waterblocks, it means the temperature between the base of the block and the water flowing through it. This means that a block's C/W is really two-fold (ignoring minor stuff like convection to air off its surface and virtually zero radiation energy exchange). The first part is conduction of the heat through the block structure. The second part is the convective resistance getting that heat into the water. This second part is purely a surface phenomenon and other than how the heat is distributed over the surface, conductivity has nothing to do with it. This is why dropping a block's conductivity by 10% via cold-working is not so bad. Conduction through the block is probably (just an off-the-cuff guess here) about 50% (ideal would be 50%) of the C/W of a block. So improving conductivity by 10% would mean a delta-T reduction of about 5% of the delta-T that occurs from block base to fluid. A change of this magnitude is piss in the wind when compared to the variation that Bill gets from one block mounting to the next. The only way this is measurable is a test geared specifically toward a measurement of conductivity, which not even Bill's fancy get-up could manage. I'm all for folks exploring the unknown and seeing what's possible, but I prefer to be realistic about the potential benefit. The potential of this one is not so big, especially when compared against using "good" copper versus a lower conductivity alloy or aluminum.