Investigation of the F-Shape Manifold for Air-BioCNG Mixing in Twin-Cylinder Dual-Fuel Diesel Engine

Recently, biologically produced compressed natural gas (bioCNG) is being considered as an alternative to the fossils. The present study evaluates the twin-cylinder engine of dual-fuel mode with diesel as a pilot and bioCNG as a primary fuel. It incorporates an F-shape intake manifold with the port-fuel injector for bioCNG induction. This study aims to analyse the flow behaviour of the air-bioCNG mixture for different bioCNG substitutions. The manifold geometry is modelled based on its actual dimensions. The flow simulation of the mixture of air and bioCNG inside the F-shape inlet manifold is executed using computational fluid dynamics. The experiments at different substitutions used as the boundary conditions, such as the inlet pressure and air and bioCNG mass flow rates. The parametric distributions in the manifold are analysed to examine the flow characteristics of the mixture. It is found that the flow characteristics show improvement concerning an increase in the substitution rate in terms of gas request ratio (GRR), with a peak velocity of 37.2 m/s in 80% bioCNG.