I'm trying to build a fanless computer case for a small electronic device. I'm trying to figure out what type of heat-sink material I should use. I have a solid copper rod about 3cm in length with a radius of .05cm. I've determined and calculated the density, specific heat, thermal conductivity, thermal diffusivity, initial temperature at one end of the rod, and total power output (20 watts). Aside from me performing some experiment and measuring the temperature at various points through out the solid rod, is there a way I can initially calculate the temperature change at certain points from the information I have? In the end, I want to be able to see if the heat from the initial point of contact will move/disperse up the solid rod to the other end fast enough and what's its temperature if/when it reaches that point. This is just a solid copper cylindrical rod with no fins or cuts. It's just a block of copper that's being used as a heat-sink between my devices cpu and outside case. If the copper rod can't move the heat fast enough or at all, I want to be able to try other materials such as aluminum.