A radiation detector, oriented as shown in the sketch, is used to estimate heat loss through an

Question:

A radiation detector, oriented as shown in the sketch, is used to estimate heat loss through an opening in a furnace wall. The opening in this case is circular with a diameter of 2.5 cm. The detector has a surface area of 0.10 cm²and is located 1 m from the furnace opening. Determine the amount of radiant energy reaching the detector under two conditions:

a. The detector has a clear view of the opening

b. The opening is covered by a semitransparent material with spectral transmissivity given by

TA = 0.8 for 0<1< 2 µm TA = 0 for 2 µm < A< ∞ Opening diameter = 25 cm %3D Furnace 30° %3D T = 1500 K Y Detector