Two large diffuse gray parallel plates, separated by a small distance, have surface temperature of 400 K and 300 K. If the emmissivities of the surface are 0.8 and the Stefan-Boltzmann constant is 5.67 x 10^-8 W/m3K4, What is the net radiation heat exchange rate in KW/m3 between the two plates?
Two large diffuse gray parallel plates, separated by a small distance, have surface temperature of 400 K and 300 K. If the emmissivities of the surface are 0.8 and the Stefan-Boltzmann constant is 5.67 x 10^-8 W/m3K4, What is the net radiation heat exchange rate in KW/m3 between the two plates?
Net radiation heat exchange rate,
\[\sigma = 5.67 \times 10^{-8}\,W/m^{2}K^{4}\]
\[\frac{Q}{A}=\frac{\sigma \left ( T_{1}^{4} – T_{2}^{4} \right )}{\frac{1}{\varepsilon _{1}}+\frac{1}{\varepsilon _{2}}-1}= \frac{ 5.67 \times 10^{-8}\left ( 400^{4} – 300^{4} \right )}{\frac{1}{0.8}+\frac{1}{0.8}-1} = 661.5\,W/m^{2} = 0.66\, kW/m^{2}\]
