The configuration of a furnace can be approximated as an equilateral triangular duct which is sufficiently long that the end effects are negligible. The hot wall is maintained at T1 = 900 K and has an emissivity e1=0.8. The cold wall is at T2 = 400 K and has an emissivity e2 = 0.8. The third wall is reradiating zone for which Q3 = 0. The accompanying sketch illustrates the configuration. Calculate the net radiation heat flux leaving the hot wall.
