Heat transfer in turbulent flow on a horizontal tube falling film evaporator. a theoretical approach

A simplified theoretical approach for the prediction of evaporation (no-nucleate boiling) heat transfer coefficient in a horizontal tube falling film is proposed. The correlation is derived from an analysis of the thermal boundary layer under the assumption of turbulent flow regime and taking into account the thermal developing region. A diagram to evaluate $\text{h}$(μ²/ρ²gk³)^{$\text{1}\text{3}$} as a function of Re and Pr is proposed.A regression analysis of the numerical computations allows us to provide a dimensionless formula $\text{h}$(μ²/ρ²/gk³)^{$\text{1}\text{3}$} = 0.046 Re^0.18Pr^0.47 valid in the ranges Re = 1500–5000 and Pr = 1–5.