Design of falling‐film evaporators in the dairy industry

The design of falling-film evaporators for dairy products has hitherto been based on empirical correlations for the heat transfer in the evaporator tubes. With a one-tube evaporator, experiments with whole and skim milk were performed to determine the heat transfer and pressure drop in evaporator tubes. Two evaporation regimens are important for dairy products : convection boiling at lower heat fluxes and nucleate boiling at larger heat fluxes. Correlations have been derived. Based on the results, a computer program for the optimal design of multistage falling-film evaporators for dairy products has been developed