THERMAL RADIATION FROM A NODAL NETWORK ON LARGE CIRCULAR FINS
Three methods are compared in calculating the heat radiated from fins of arbitrary shape. The discussion pertains to large circular fins of 0.07 to 0.15 m in diameter, however, the theory applies to any fin shape for which geometric view factors and surface emittances are known. For uncoated stainless steel, values may be 0.2 for a 2B finish or 0.4 for an as-received rolled finish. In this range of emittances and in the range of ratios of fin length to spacing commonly used (L/h of 2 to 4), William's optical formula predicts more radiant heat dissipated from a cask than the other two theories predict by 10 percent or more in a nonconservative direction during normal operation of the cask. For surfaces of low emittance the method of Sparrow, which includes energy reflected from each surface to every other surface on the fins and cask, is recommended.