E5.12 Condensing Coefficient - Vertical Tube

Example 5.12: Calculate the condensing coefficient for a vertical tube with an inside diameter of 0.62 in if steam is condensing on the inside of the tube at a rate of 50 lb/h.

Use the following data:

Condensate:

Density, ρ_L = 60 lb/ft³,

Specific heat, c_L = 1.0 Btu/(lb·°F),

Absolute viscosity, μ_L = 0.72 lb/(ft·h),

Thermal conductivity, k = 0.395 Btu/(h·ft·°F),

Condensation rate, W = 50 lb/h

Vapor:

Density, ρ_G = 0.0372 lb/ft³,

Viscosity, μ_G = 0.0313 lb/(ft·h)

Inside diameter of the tube, d_i = 0.62 in, number of tubes, n = 1, g_c = 4.18´10⁸ ft/h²

Solution: The condensate rate per unit periphery, Γ, can be calculated as

And the terminal Reynolds number can be found to be

And the Prandtl number for the condensate can be calculated to be 1.82. We can find f_D to be 0.21. The heat transfer coefficient, h_o, is found as

Dukler parameter, A_D, can be found to be

Using the value of terminal Reynolds number and Dukler parameter, we see that

(Table on Page 7-50 Chopey) and corrected heat transfer coefficient, h, can be calculated to be