Unformatted text preview: of radiation heat transfer to the liquid nitrogen is to be determined. Assumptions 1 Steady operating conditions exist 2 The surfaces are opaque, diffuse, and gray. 3 Convection heat transfer is not considered. 4 The thermal resistance of the tank is negligible. Properties The emissivities of surfaces are given to be ε 1 = 0.1 and ε 2 = 0.8. D 2 = 3 m T 2 = 240 K ε 2 = 0.8 D 1 = 2 m T 1 = 100 K ε 1 = 0.1 Vacuum Liquid N 2 Analysis The net rate of radiation heat transfer to liquid nitrogen can be determined from ( ) ( ) W 227 = ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − + − ⋅ × = ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − + − = − 2 2 4 4 4 2 8 2 2 2 2 1 2 2 1 4 2 4 1 1 12 m) (1.5 m) 1 ( 8 . 8 . 1 1 . 1 ] K 100 K 240 )[ K W/m 10 67 . 5 ]( m) 2 ( [ 1 1 ) ( r r T T A Q & 1226...
View
Full Document
 Fall '10
 Dr.DanielArenas
 Thermodynamics, Mass, Heat, Radiation, Heat Transfer

Click to edit the document details