Thermodynamics HW Solutions 730

Thermodynamics HW Solutions 730 -...

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Chapter 9 Natural Convection 9-37 "!PROBLEM 9-37" "GIVEN" L=60 "[m]" D=0.0603 "[m]" T_s=170 "[C], parameter to be varied" T_infinity=20 "[C]" epsilon=0.7 T_surr=T_infinity eta_furnace=0.78 UnitCost=0.538 "[$/therm]" time=24*365 "[h]" "PROPERTIES" Fluid$='air' k=Conductivity(Fluid$, T=T_film) Pr=Prandtl(Fluid$, T=T_film) rho=Density(Fluid$, T=T_film, P=101.3) mu=Viscosity(Fluid$, T=T_film) nu=mu/rho beta=1/(T_film+273) T_film=1/2*(T_s+T_infinity) sigma=5.67E-8
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Unformatted text preview: "[W/m^2-K^4], Stefan-Boltzmann constant" g=9.807 "[m/s^2], gravitational acceleration" "ANALYSIS" delta=D Ra=(g*beta*(T_s-T_infinity)*delta^3)/nu^2*Pr Nusselt=(0.6+(0.387*Ra^(1/6))/(1+(0.559/Pr)^(9/16))^(8/27))^2 h=k/delta*Nusselt A=pi*D*L Q_dot=h*A*(T_s-T_infinity)+epsilon*A*sigma*((T_s+273)^4-(T_surr+273)^4) Q_gas=(Q_dot*time)/eta_furnace*Convert(h, s)*Convert(J, kJ)*Convert(kJ, therm) Cost=Q_gas*UnitCost 9-31...
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