23.26 A circular heater, measuring 20cm in diameter, has its surface temperature maintained at 1000C. The bottom of a tank, having the same diameter, is oriented parallel to the heater with a separation distance of 10cm. The heater surface is gray (=0.6) and the tank surface is also gray (=0.7). Determine the radiant energy reaching the bottom of the tank if a. the surroundings are black at 27C b. the space between the two cylindrical surfaces is enclosed by an adiabatic surface 23.26 A circular heater, measuring 20cm in diameter, has its surface temperature maintained at 1000C. The bottom of a tank, having the same diameter, is oriented parallel to the heater with a separation distance of 10cm. The heater surface is gray (=0.6) and the tank surface is also gray (=0.7). Determine the radiant energy reaching the bottom of the tank if a. the surroundings are black at 27C b. the space between the two cylindrical surfaces is enclosed by an adiabatic surface