DESIGNATION OF THE HEAD LOSS COEFFICIENT IN FITTINGS CFD

Abstract

The optimization of pumping systems is important because it leads to an increment of improved energy efficiency. This study analyzes the hydraulic behavior of clean water through pressurized fittings which is analyzed numerically. The numerical experiment is carried out using Ansys Fluent software. The flow characterization through the fittings was performed using the coefficient of minor losses (KL). Two short radius elbows of 45° and 90°, and a PVC tee (simple) were used. The procedure used for the development of the numerical experimentation in this study is as follows: geometry construction, discretization, boundary conditions, configuration of the numerical simulation parameters, validation, CFD parametric study, and the analysis of results. The results of the flow simulation on the meshes showed a high sensitivity to the mesh size. To determine the optimal element size, a mesh independence study was performed, which consisted of refining the mesh to stable values. The numerical results were compared with values calculated using conventional equations for minor losses in the fittings. The KL values were characterized by two methods: in the first one the behavior of KL with respect to Reynolds number in turbulent flow was studied, in the second one the relative percentage of loss error was determined in comparison with previous investigations on this subject. The numerical results showed an acceptable relative error for the three simulated fittings.