Respuesta :
Answer:
The surface temperature of the metal foil is 453.645 K
Explanation:
The properties of the air at 100°C and 1 atm are the follows:
ρ = density = 0.9458 kg/m³
Cp = specific heat = 1009 J/kg K
Pr = 0.7111
The surface area of the plate is equal to:
[tex]A=WL[/tex]
Where
W = width of the plate = 0.2 m
L = length of the plate = 0.5 m
[tex]A=0.2*0.5=0.1m^{2}[/tex]
The average friction coefficient is equal to:
[tex]C_{f} =\frac{F}{\frac{A\rho V^{2} }{2} }[/tex]
Where
F = drag force = 0.3 N
V = velocity of air flow = 100 m/s
[tex]C_{f} =\frac{0.3}{\frac{0.1*0.9458*100^{2} }{2} } =0.000634[/tex]
The average heat transfer coefficient is equal to:
[tex]h=\frac{C_{f}\rho VC_{p} }{2Pr^{2/3} } =\frac{0.000634*0.9458*100*1009}{2*(0.7111x^{2/3}) } =37.972W/m^{2} K[/tex]
The surface temperature is:
[tex]T_{s} =\frac{q}{h} +T\alpha[/tex]
Where
q = heat flux = 6100 W/m²
Tα = temperature of the air = 20°C = 293 K
[tex]T_{s} =\frac{6100}{37.972} +293=453.645K[/tex]
