Effect of Cylindrical Turbulators on the Mixing Process in Basic Venturi Gas Mixer Using OpenFOAM

Abstract

This study was devoted to improving the mixing quality in a Venturi gas mixer. It is well known that the performance of industrial gas engines strongly depends on the quality of air and fuel mixture and therefore on its homogeneity. Incorrect mixture proportions may lead to unstable operation of the entire industrial gas engine and excessive emissions exceeding environmental standards of the European Union. The effectiveness of the mixing process in a Venturi gas mixer depends on many factors, i.e. correct proportions between Air inlet, Venturi Throat diameter, as well as gas inlet area. To improve the intensification of the whole mixing process, as well as to increase the mixing time between gas and air, it was decided to insert disturbing elements in form of cylindrical turbulators into the Venturi pipe. Therefore numerical calculations were performed for the most commonly consumed by industrial gas engines lean Air-Fuel mixture, with an air excess coefficient ratio of λ = 1.6. In numerical analysis, OpenFOAM software was used to investigate the impact of cylindrical turbulators on the whole mixing process in a basic Venturi gas mixer. Particular attention was focused on the Air-Fuel Ratio (AFR) changes, Turbulent Kinetic Energy (TKE) and Pressure loss [Pa], which is one of the most qualitative evaluation parameters of a gas mixer.