Calculation of Thermal Conductivity

1.Heat Transfer by Radiation
E_r=4.96p_s[(T₁/100)^４>-(T₂/100)^４]/(T₁-T₂)

 

    Er=4.96ps[(T1/100)４>-(T2/100)４]/(T1-T2)

    Er : Radiation Heat Transfer Coefficient ㎉/㎡hr℃  -

    T1 : Surface Temperature of Heating Element (Absolute Temperature) –

    T2 : Surface Temperature of Heat Sink (Absolute Temperature)  -

    ps : Surface Emissivity of Heating Element

 

In case of atmospheric radiation, T2 refers to atmospheric temperature

 

2.Emissivity Coefficients

 

3.Heat Transfer by Convection

   3-1)  Heat Transfer by Natural Convection

          When a fluid flows outside a horizontal tube

hd/γ=0.525[(d³ρ²βg(Δt)/μ²)(C_pμ/λ)]^0.25 When a fluid flows outside a vertical tube
hd/γ=0.64[(d³ρ²βg(Δt)/μ²)(C_pμ/λ)]^0.25
3.  Heat Transfer by Conduction