Chapter 7 External Forced Convection7-97A spherical tank used to store iced water is subjected to winds. The rate of heat transfer to the iced water and the amount of ice that melts during a 24-h period are to be determined. Assumptions1Steady operating conditions exist. 2Air is an ideal gas with constant properties. 7 The pressure of air is 1 atm. PropertiesThe properties of air at 1 atm pressure and the free stream temperature of 30°C are (Table A-15) kg/m.s10872.1/sm10608.1CW/m.02588.0525-−∞×=×=°=μυk7282.0Prkg/m.s10729.15C0@,=×=−°sAnalysis(a) The Reynolds number is 62510304.1/sm10608.1m)(3.02m/s1000/3600)(25Re×=××=υ=−∞DVThe Nusselt number corresponding to this Reynolds number is determined from 105610729.110872.1)7282.0()10304.1(06.0)10304.1(4.02PrRe06.0Re4.024/1554.03/265.064/14.03/25.0=⎟⎟⎠⎞⎜⎜⎝⎛×××+×+=⎟⎟⎠⎞⎜⎜⎝⎛μμ++==−−∞skhDNuand C.W/m05.9)1056(m02.3CW/m.02588.02°=°==NuDkhIn steady operation, heat transfer through the tank by conduction is equal to the heat transfer from the outer surface of the tank by convection and radiation. Therefore, &&&&()(,,QQQQTTRhA TTATTs outs insphereoosurrs out
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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.