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7/25/2019 Natural Convtion
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NATURAL CONVECTION HEAT TRANSFER
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Natural convection heat transfer takesplace when a vertical hot plate comesin contact with a quiescent colderuid.
Fluid layer in contact with the hot platehaving lower density ows upwardand the space is lled up by theheavier colder uid coming from thebulk.
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-g
Pressure gradient in theboundary ayer !ust be
e"ua to the #ressuregradient in the "uies$entregion%
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Energy e"uation
The &rst ter! on RHS isbuoyan$y 'or$e in(o(ingdensity di)eren$e *hi$horiginates the +o*%
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THE ,O,ENTU, AN ENER./E0UATION ARE COUPLE 1/RE,OVIN. ENSIT/ AN
INTROUCIN. TE,PERATURE%
The 'un$tiona 'or! o' heattrans'er $oe2$ient his gi(en by3
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NON-I,ENSIONAL FOR, OF .OVERNIN.E0UATION
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LCIS CHARACTERISTIC LEN.THV IS CHARACTERISTIC VELOCIT/
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.RASHOF NU,1ER
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ANAL/SIS OF NATURAL CONVECTION
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RA/LEI.H NU,1ER
N 8 9:6 ;a!inar+o*