Answer:
Q=3198.744 W/m
Explanation:
Given that
Air temperature=20 C
Velocity V= 35 m/s
Temperature of surface= 60 C
Length of plate= 75 cm
Now first find the properties of air at mean temperature of 20 and 60,it means that properties of air at temperature 40 C
[tex]\rho=1.12 \frac{Kg}{m^3}[/tex]
[tex]\nu =1.69\times 10^{-5}\frac{m^2}{s}[/tex]
[tex]K=0.027\frac{W}{m-K}[/tex]
Pr=0.71
Lets find the Reynolds number
[tex]Re=\dfrac{vL}{\nu }[/tex]
[tex]Re=\dfrac{35\times0.75}{1.69\times 10^{-5}}[/tex]
[tex]Re=15.53\times10^5[/tex]
So this is turbulent flow
Nusselt equation of turbulent flow
[tex]Nu=0.037Re^{\frac{4}{5}}Pr^{\frac{1}{3}}[/tex]
Now by putting the values
[tex]Nu=0.037\times (15.53\times10^5)^{\frac{4}{5}}\times 0.71^{\frac{1}{3}}[/tex]
Nu=2961.68
We know that
[tex]NU=\dfrac{hL}{K_{air}}[/tex]
So
[tex]2961.68=\dfrac{h\times 0.75}{0.027}[/tex]
[tex]h=106.68\frac{W}{m^2-K}[/tex]
So heat transfer
Q=hAΔT
Q=106.68 x 0.75 x 1 x (60-20)
Q=3198.744 W/m
