A long rod of 60-mm diameter and thermophysical properties rho=8000 kg/m^3, c=500J/kgK, and k=50 W/mK is initally at a uniform temperature in a forced convection furnace maintained at 750K. The convection coeffiecent is estimated to be 1000 W/m^2K.

What is the centerline temperature of the rod when the surface temperature is 550K?

Respuesta :

Answer:

Tc = 424.85 K

Explanation:

Given that,

[tex]D = 60 mm = 0.06 m[/tex]

[tex]\rho = 8000 kg/m^3[/tex]

[tex]k = 50 w/m . kc = 500 j/kg.k[/tex]

[tex]h_{\infty} = 1000 w/m^2t_{\infity} = 750 kt_w = 500 K[/tex]

[tex]surface area = As = \pi dL \\\frac{As}{L} = \pi D = \pi \timeS 0.06[/tex]

HEAT FLOW Q  is

[tex]Q = h_{\infty} As (T_[\infty} - Tw) = 1000 \pi\times 0.06 (750-500)[/tex]

 = 47123.88 w per unit length of rod

volumetric heat rate

[tex]q = \frac{Q}{LAs}[/tex]

[tex]= \frac{47123.88}{\frac{\pi}{4} D^2 \times 1}[/tex]

[tex]q = 1.66\times 10^{7} w/m^3[/tex]

[tex]Tc = \frac{- qR^2}{4K} + Tw[/tex]

[tex]= \frac{ - 1.67\times 10^7 \times (\frac{0.06}{2})^2}{4\times 50} + 500[/tex]

  = 424.85 K