Thermodynamics HW Solutions 630

Thermodynamics HW Solutions 630 - Chapter 7 External Forced...

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Unformatted text preview: Chapter 7 External Forced Convection 7-100 Steam is flowing in a stainless steel pipe while air is flowing across the pipe. The rate of heat loss from the steam per unit length of the pipe is to be determined. Assumptions 1 Steady operating conditions exist. 2 Air is an ideal gas with constant properties. 3 The pressure of air is 1 atm. Properties Assuming a film temperature of 10 ° C, the properties of air are (Table A-15) 7336 . Pr and /s, m 10 426 . 1 C, W/m. 02439 . 2-5 = × = υ ° = k Analysis The outer diameter of insulated pipe is D o = 4.6+2 × 3.5=11.6 cm = 0.116 m. The Reynolds number is 4 2 5 10 254 . 3 /s m 10 426 . 1 m) m/s)(0.116 (4 Re × = × = υ = − ∞ o D V The Nusselt number for flow across a cylinder is determined from ( ) [ ] ( ) [ ] . 107 000 , 282 10 254 . 3 1 7336 . / 4 . 1 ) 7336 . ( ) 10 254 . 3 ( 62 . 3 . 000 , 282 Re 1 Pr / 4 . 1 Pr Re 62 . 3 . 5 / 4 8 / 5 4 4 / 1 3 / 2 3 / 1 5 . 4 5 / 4 8 / 5 4 / 1 3 / 2 3 / 1 5 ....
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This note was uploaded on 01/22/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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