Process Modeling and Optimization of Design Parameters in a Falling Film Plate and Frame Evaporator

A. Donaldson [1], A. Thimmaiah [2],
[1] Dalhousie University, Halifax, Nova Scotia, Canada
[2] National Institute of Technology Karnataka, Mangalore, Karnataka, India.

COMSOL Multiphysics® software is used to explore the impact of distributor width on the film thickness, and the resulting sensitivity of overall thermal efficiency in a plate and frame triple-effect evaporator. A stable film is crucial to maintain a minimum wetting rate, to circumvent the “dry-out condition”. The hydrodynamics of stable film development as a function of distributor width was investigated using the level-set based laminar two-phase-fluid flow model. The vapor generation in an effect is largely dependent on the overall heat transfer coefficient of each effect, which is controlled by the film thickness. Hence the broader implication of this paper is to verify the final design based on analytical film thickness predictions, with correlations from literature.