Investigation of the effects of design geometry on effective flow distribution in falling film evaporators

Falling film evaporators are widely used in the food industry to concentrate products. Evaporation process is the process of increasing the dry matter ratio by removing the water in the product. With the development of modern social structure, the pursuit for the better has led to the need for rapid developments in evaporator technology in order to meet the needs. In the literature, all heat transfer approaches applied are based on the assumption that the liquid is completely homogeneously and effectively distributed over the heating surfaces. This constraint and inadequacy seen in the literature formed the motivation source of this study. Within the scope of this thesis study, the design criteria of the falling film evaporators were examined, and design key points were formed depending on the parameters required for optimum design. It is modeled by establishing a mathematical relationship between flow distribution and heat transfer. With the modelling, it is aimed to create the most suitable design geometry according to the flow distribution. With the study, the assumption parameters for the heat transfer approaches were defined as inputs; the theory of evaporation integrated with flow distribution model was explained. The optimum design inputs obtained as a result of the numerical analysis were compared with the Computational Fluid Dynamics (CFD) flow distribution simulation; design verification has been carried out. It has been observed that the smaller evaporation volumes, distribution holes and short hydrolic jet heights are more effective in terms of both heat transfer and flow distribution. With this study, optimization definition for vertical film evaporators is introduced to the literature as the concept of integrated heat transfer theory with flow distribution.