# Heat transfer

*label*Engineering

*timer*Asked: Jun 29th, 2018

**Question description**

Two blackbody rectangles, each 6 ft by 12ft, are parallel, directly opposed, and 12ft apart. One rectangle is held at Tl= 200°F;the other is at Tz= 600°F.Find: (a)the rate of radiant heat transfer q1-2,(6)the rate at which the 200 OF rectangle is losing energy of the surroundings are at 0OR, and (c)the rate at which rectangle is losing energy if the surroundings are considered as a single blackbody at 70OF. Ans. For F1-2=: 0.115: ( a ) -15 224 Btu/h; ( b ) 5499.4 Btu/h; ( c ) -3118.3 Btu/h