Respuesta :
Answer:[tex]180.86^{\circ}C[/tex]
Explanation:
Properties of Fluid at [tex]100^{\circ}C[/tex]
[tex]P_r=0.711[/tex]
[tex]\rho =0.9458 kg/m^3[/tex]
[tex]c_p=1009 J/kg/k[/tex]
[tex]Flux =6100 W/m^2[/tex]
Drag force [tex]F_d=0.3 N[/tex]
[tex]A=0.2\times 0.5=0.1 m^2[/tex]
drag force is given by
[tex]F_d=c_f\cdot A\rho \frac{v^2}{2}[/tex]
[tex]c_f=\frac{2F_d}{\rho Av^2}[/tex]
[tex]c_f=\frac{2\times 0.3}{0.9458\times 0.1\times 100^2}[/tex]
[tex]c_f=\frac{0.6}{945.8}[/tex]
[tex]c_f=0.000634[/tex]
we know average heat transfer coefficient is
[tex]h=\frac{c_f}{2}\times \frac{\rho vc_p}{P_r^{\frac{2}{3}}}[/tex]
[tex]h=\frac{0.000634}{2}\times \frac{0.9458\times 100\times 1009}{(0.711)^{\frac{2}{3}}}[/tex]
[tex]h=37.92 W/m^2-K[/tex]
Surface Temperature of metal Foil
[tex]\dot{q}=h(T_s-T{\infty })[/tex]
[tex]T_s=\frac{\dot{q}}{h}[/tex]
[tex]T_s[/tex] is the surface temperature and T_{\infty }[/tex] is ambient temperature
[tex]T_s=\frac{6100}{37.92}+20=180.86^{\circ}C[/tex]
