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Unformatted text preview: = − υ L T T g Ra 539 . 1 05 . 2 ) 10 918 . 1 ( 197 . 197 . 9 / 1 4 / 1 4 9 / 1 4 / 1 = ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × = ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = − − L H Ra Nu 2 m 6 ) m 3 )( m 2 ( = = s A Then the rate of heat transfer by natural convection becomes W 45.0 = ° − ° = − = m 05 . C ) 5 15 ( ) m 6 )( 539 . 1 )( C W/m. 02439 . ( 2 2 1 L T T kNuA Q s conv & The rate of heat transfer by radiation is determined from ( ) ( ) W 252 = − + + − + ⋅ × = − + − = − 1 9 . 1 9 . 1 ] K 273 5 K 273 15 )[ K W/m 10 67 . 5 )( m 6 ( 1 1 1 ) ( 4 4 4 2 8 2 2 1 4 2 4 1 rad εε σ T T A Q s & Then the rate of total heat transfer becomes W 297 = + = + = 252 45 rad conv total Q Q Q & & & Discussion Note that heat transfer through the window is mostly by radiation. 1275...
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This note was uploaded on 01/24/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.
 Fall '10
 Dr.DanielArenas
 Thermodynamics, Convection, Mass, Heat, Radiation

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