Thermodynamics HW Solutions 671

Thermodynamics HW Solutions 671 - Re=(Vel*D_h)/nu...

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Chapter 8 Internal Forced Convection T_i=60 "[C]" L=12 "[m]" side=0.20 "[m]" Vel=4 "[m/s], parameter to be varied" "epsilon=0.3 parameter to be varied" T_o=10 "[C]" h_o=10 "[W/m^2-C]" T_surr=10 "[C]" "PROPERTIES" Fluid$='air' C_p=CP(Fluid$, T=T_ave)*Convert(kJ/kg-C, J/kg-C) k=Conductivity(Fluid$, T=T_ave) Pr=Prandtl(Fluid$, T=T_ave) rho=Density(Fluid$, T=T_ave, P=101.3) mu=Viscosity(Fluid$, T=T_ave) nu=mu/rho T_ave=T_i-10 "assumed average bulk mean temperature" "ANALYSIS" A=4*side*L A_c=side^2 p=4*side D_h=(4*A_c)/p
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Unformatted text preview: Re=(Vel*D_h)/nu "The flow is turbulent" L_t=10*D_h "The entry length is much shorter than the total length of the duct." Nusselt=0.023*Re^0.8*Pr^0.3 h_i=k/D_h*Nusselt m_dot=rho*Vel*A_c Q_dot=Q_dot_conv_in Q_dot_conv_in=Q_dot_conv_out+Q_dot_rad_out Q_dot_conv_in=h_i*A*DELTAT_ln DELTAT_ln=(T_e-T_i)/ln((T_s-T_e)/(T_s-T_i)) Q_dot_conv_out=h_o*A*(T_s-T_o) Q_dot_rad_out=epsilon*A*sigma*((T_s+273)^4-(T_surr+273)^4) sigma=5.67E-8 "[W/m^2-K^4], Stefan-Boltzmann constant" Q_dot=m_dot*C_p*(T_i-T_e) 8-33...
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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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