A drying oven consists of a long semicircular duct of diameter D = 1 m (Surface1). Materials to be dried cover the base of the oven (Surface 2). The wall(Surface

1) of the oven (81=0.8) is maintained at T1 = 1200 K, while the materials to be dried are considered a black body (82=1.0) is maintained at a temperature T2 = 325 K during the process. a. Calculate the view factor F12; b. Calculate the net radiation heat transfer rate from the oven wall to the material to be dried. Given: o = !5.67x108 W/m2-K and for a two-surface enclosure it is known