Unformatted text preview: − = − − ∞ ∞ o o o o o hr k Bi r r r r T T T T Water 94 ° C Hot dog The Fourier number is determined from Fig. 414a to be 20 . 47 . 94 20 94 59 15 . 1 2 = = ⎪ ⎪ ⎭ ⎪ ⎪ ⎬ ⎫ = − − = − − = = ∞ ∞ o i o o r t T T T T hr k Bi α τ The thermal diffusivity of the hot dog is determined to be /s m 10 2.017 2 7 − × = = = α ⎯→ ⎯ = α s 120 m) 011 . )( 2 . ( 2 . 20 . 2 2 2 t r r t o o ( b ) The thermal conductivity of the hot dog is determined from C W/m. 0.771 ° = ° × = αρ = − C) J/kg. )(3900 kg/m /s)(980 m 10 017 . 2 ( 3 2 7 p C k ( c ) From part ( a ) we have 15 . 1 = = o hr k Bi . Then, m 0.00165 m) 011 . )( 15 . ( 15 . = = = r h k Therefore, the heat transfer coefficient is C . W/m 467 2 ° = ° = ⎯→ ⎯ = m 0.00165 C W/m. 771 . 00165 . h h k 434...
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 Fall '10
 Dr.DanielArenas
 Thermodynamics, Conductivity, Convection, Mass, Heat, Heat Transfer, Hot dog, Thermal conductivity

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