Numerical simulation of the 3-D turbulent steady compressible flow in type T junctions and experimental validation of the total pressure loss coefficient

Abstract

Nowadays, simulation models of steady and transient compressible internal flow are essential in analyzing devices and plants where piping systems for gases and steam are required, such as, pneumatic fluid power systems, transport piping systems, inlet and exhaust systems in alternating combustion engines and compressors. Models used in the simulation of steady and transient compressible flow in junctions require local total pressure loss coefficients. These coefficients can be experimentally obtained although a experimental support highly cost is required. Moreover, the internal flow behaviour is unknown. Alternatively, these coefficients can be obtained through numerical simulation using a 3D CFD general purpose software adequately validated. This work is aimed to numerical simulation of 3D steady compressible flow at junctions “T” type. The geometrical characteristics and the different types of mesh used during simulations will be described, as well as numerical schemes, turbulence models, boundary conditions and more adequate simulation hypothesis. The applied procedure to experimental validation of the numerical results for the total pressure loss coefficient in steady compressible flow in “T” type junctions will be presented. The experimental results were obtained in a flow bench for several combining and dividing flow configurations and for different mass flow ratios between branches as a function of local Mach number at intersection point in the common branch. The comparison of numerical results with experimental and reference data, allow us selecting and adjusting simulation parameters, such as optimal turbulence model, boundary conditions, grid sensitivity and size, as well as most suitable adaption method in each case, discretization model and algorithm to solve the equations