A horizontal semitransparent plate is uniformly irradiated from above and below, while air at \(T_{\infty}=310 \mathrm{~K}\) flows over the top and bottom surfaces, providing a uniform convection heat transfer coefficient of \(h=50 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). The absorptivity of the plate to the irradiation is 0.40 . Under steady-state conditions measurements made with a radiation detector above the top surface indicate a radiosity (which includes transmission, as well as reflection and emission) of \(J=5500 \mathrm{~W} / \mathrm{m}^{2}\), while the plate is at a uniform temperature of \(T=360 \mathrm{~K}\).

Determine the irradiation \(G\) and the emissivity of the plate. Is the plate diffuse-gray \((\varepsilon=\alpha)\) for the prescribed conditions?

Transcribed Image Text:

Semitransparent plate, 77 Detector Th Th