E5.13 Condensation in Horizontal Tube

Example 5.13: Calculate the effective condensate coefficient for a horizontal tube with an inside diameter of 0.62 in and a length of 9 ft for a fluid at a rate of 126 lb/h.

Use the following data:

Density of condensate, ρ = 50 lb/ft³; absolute viscosity, μ = 0.25 lb/(ft·h)

Thermal conductivity, k = 0.08 Btu/(h·ft·°F); specific heat, c = 0.55 Btu/(lb·°F)

Internal diameter of tube, d_i = 0.62 in; number of tubes, n = 1

Condensation rate, W = 126 lb/h; length of a tube, L = 9 ft; g_c = 4.18´10⁸ ft/h².

Solution: For steam condensing in a horizontal tube, and assuming that flow is stratified, heat transfer coefficient can be found to be

The parameter, A_s, can be calculated as

Now this value of A_s gives h/h_c of 0.92 (Table on page 7-50, Chopey) and we can find h as 374 Btu/(h·ft²·°F).