Numerical Study of an Axisymmetric Diffuser with Sudden Expansion Using Four Different Turbulence Models

The article considers the turbulent flow in an axisymmetric diffuser with sudden expansion.Axisymmetric diffusers with sudden expansion are widely used in various engineering applications, including aerodynamics and hydraulics.The main objective is to analyze flow characteristics such as velocity, pressure, and turbulence distributions in the region behind the expansion.Particular attention is paid to the development of recirculation zones, the occurrence of secondary flows, and the influence of geometric parameters on the overall flow pattern.To solve the problem, a system of Reynolds-averaged Navier-Stokes equations is used.To find the coefficient of turbulent viscosity, the SA,turbulence models are used.The COMSOL Multiphysics 6.1 package is used to calculate these models.The obtained numerical results are compared with experimental data.Comparison of the time costs for solving this problem of the considered models showed that the SA model is the most economical.