Study of the Influence of Geometric Parameters in an Innovative Scraped Surface Heat Exchanger With Helical Ribbon

Abstract

This work aims to characterize the hydrodynamic and thermal behaviors in an innovative scraped surface heat exchanger (SSHE) equipped with helical ribbon by means of the numerical simulation approach. In this study, the conservation equations of continuity, momentum, and energy in the laminar, steady-state and isothermal conditions are resolved using a specific computational fluid dynamics (CFD) code based on the 3D finite volume method. The effects of the gap between the exchanger wall and the tip of the ribbon, the ribbon width, and the number of turns in the ribbon on the hydrodynamic and thermal behaviors are studied. Varying the gap values leads to reveal an optimum value giving the highest heat transfer coefficient. Moreover, numerical results have shown that increasing the ribbon width improves the heat transfer. Furthermore, the influence of the number of turns is carried out for Reynolds number ratios (Rer/Rea) inferior and superior to 1. Results revealed that increasing the number of turns avoids the back-mixing phenomenon and thus improves the heat transfer. In this study, the establishment of correlation is determined with the introduction of dimensionless and geometrical groups to predict the heat transfer coefficient in SSHE.