ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
Numerical Study of Falling Film Evaporation on a Horizontal Tube Bundle
The falling film evaporation on horizontal tubes offers distinct advantages over the flooded type evaporators, because of which they find applications in refrigeration and air-conditioning and desalination. The present work focuses on the influence of tube bundle arrangement on the heat transfer characteristics. A 2-D CFD analysis is carried out using ANSYS Fluent 16.0®, employing Multiphase-Volume of Fluid (VOF) method. Further, Lee-phase change model available under Evaporation and Condensation setting in Fluent is used for the heat transfer and mass transfer analysis. The fluids used for the analysis are water and water vapor, with liquid distributed from a slot provided on top of the tube bundle. The numerical scheme for carrying out the CFD analysis is verified by validating the numerical results against the experimental data available in the literature. Grid and time-step independence studies are carried out for choosing the optimum mesh and time-step, respectively. The parameters such as inlet fluid velocity or falling film Reynolds number, tube pitch, degree of wall superheat, number of horizontal tube rows is kept constant for a quantitative comparison between the heat transfer coefficients for the falling film evaporation on a column of horizontal tubes, inline and staggered bundle arrangements. Variation of the falling film thickness and the heat transfer coefficient down the column of the tubes are also presented.