A solid sphere of 1 m diameter at 600 K is kept in an evacuated equilateral triangular enc...

A solid sphere of 1 m diameter at 600 K is kept in an evacuated equilateral triangular enclosure (a tetrahedron) whose side length is L. Note that for the sphere to touch the tetrahedron’s surfaces, the tetrahedron’s side length should be . The emissivity of the sphere is 0.45 and the temperature of the enclosure is 420 K. If heat is generated uniformly within the sphere at a rate of 3100 W, determine (a) the view factor from the enclosure to the sphere and (b) the emissivity of the enclosure.

FIGURE P13–55