In reply to David Roberson's message of Thu, 15 Jan 2015 10:18:27 -0500: Hi, [snip] >The amount of positive feedback can be adjusted by establishing the proper >ratio of sphere surface area to volume. As the pellet becomes larger the >surface area varies as the square of the radius. At the same time the volume >varies with the cube of the radius. In an ideal case that suggests that the >feedback ratio would vary directly with radius. If some form of insulating >material is coated upon the outer surface the fuel volume can be reduced >considerably. > Take into account that this is only valid for a single separate sphere. Once they are all bundled together, heat leaving one will enter another, so in the limit, the surface area is reduced to the external surface area of the conglomeration.
Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
