quote:I remember asking Hall about aluminum radiators vs. the brass ones and he said that nope, the aluminum isn't even as good as the brass.
In his opinion the aluminum anything was just for weight savings. I supose that means engine blocks also.
Doug, I don't understand Hall's conclusion;
FYI metals that are good thermal conductors tend to be good electrical conductors as well. Below is the thermal conuctivity of some common metals in W/m-K (Watts per meter Kelvin)
Ag (Silver) 428, Cu (Copper) 398, Au (Gold) 315, Al (Aluminum) 247, Brass (Cu 70%, Zn 30%) 115, Cast Iron (depending on quality) 44-52.
The precious metals are best, but obviously prohibitive in our aplications from a cost perspective, but they are extensively used in high end electronics. As you can see Al is considerably better than brass. Cu is the only real contender and hence its extenisve use in industry.
If we take the analysis a step further and look at denisty (g/cm3 or mass per unit volume) of the same metals vis;
Ag 10.5, Cu 8.9, Au 19.3, Al 2.7, Brass ~8, Cast Iron ~7.
One can easily work out that Al is by far the best metal on a thermal conductivity per unit weight basis.
Going back to the original question from Blaine, which compares Al to cast iron; The answer is 'Yes', one would expect much better heat transfer in a Al block vs. that of cast iron. The trick is in ensuring there is sufficient dissipation of that heat away from the Al block (i.e. cooling) or the whole system simply operates at a higher equilibrium temperature.
Julian