Film boiling occurs on the surface of a sphere of temperature
T_(S)=354\deg C
and diameter
D=2cm
which is plunged in a bath of saturated water at atmospheric pressure. The sphere is made out of polished copper. (a) Calculate the heat transfer coefficient due to convection,
/bar (h)_(D)
, the correction due to radiation,
/bar (h)_(rad)
, and the total heat transfer rate from the copper ball to the water pool. For the emissivity of the copper surface, assume that
\epsi lon_(w)=0.05
. (b) Model the copper sphere as a lumped capacitance, and calculate its new temperature 10 s after the start of film boiling. For (b) ,consider the following relation for copper ball as capacitance:
-\rho c_(P)V(dT_(S))/(dt)=q_(S)