Reference no: EM13947739

Liquid oxygen, which has a boiling point of 90 K and a latent  heat  of  vaporization  of  214  kJ/kg,  is  stored  in a spherical container whose outer surface is of 500-mm diameter and at a temperature of -10°C. The container is housed in a laboratory whose air and walls are at 25°C.

(a) If the surface emissivity is 0.20 and the heat transfer coefficient associated with free convection at the outer surface of the container is 10 W/m2 · K, what is the rate, in kg/s, at which oxygen vapor must be vented from the system?

(b) Moisture in the ambient air will result in frost forma- tion on the container, causing the surface emissivity to  increase.  Assuming  the surface  temperature  and convection   coefficient   to   remain   at   -10°C   and 10 W/m2 · K, respectively, compute the oxygen evap- oration rate (kg/s) as a function of surface emissivity over the range 0.2 s 0.94.