Plenum Research Papers - Academia.edu (original) (raw)

In automotive technology, an intake manifold is the component of an engine that transports the air-fuel mixture to the engine cylinders. The main purpose of the intake manifold is to evenly distribute the combustion mixture to each intake port of the engine cylinder. Even distribution is important to optimize the volumetric efficiency and performance of the engine, but the major problem in the thesis was to identify that; to achieve the even distribution of flow at each cylinders, to select the best turbulence model for the analysis of manifold using computational fluid dynamics, to achieve the maximum mass flow rate through the restricted size C-D nozzle, to maintain the equal pressure throughout the plenum, to propagate back the higher pressure column of air to intake port within the duration of the intake valve’s closure. To achieve the even flow of distribution and improve the volumetric efficiency, author divided his analysis into three different part restrictor, plenum, and cylinder runner and then analyzed the final intake manifold. Dividing the work into three different part and then combine them as single manifold part provide the greater refinement in the result and act as meshing of manifold. To select the best turbulence model for this study, author took the design data of existing experimental model and find that Spalart-Allmaras model was approximately same as the experimental model. For designing the nozzle, author selected the four design variables; nozzle inlet diameter, inlet curvature radius, diffuser half angle and diffuser length with five level of each variable. With these four variable and five level of each variable, author had need to perform 625 experiments, but he design the matrix by the help of Taguchi method using statistical tool “Minitab” and perform only 25 experiment in CFD package “Ansys Fluent”, to find the best result for restrictor, author again use the statistical tool to analyze the design matrix, and then predict the best result for restrictor. To propagate back the higher pressure column of air to intake port within the duration of the intake valve’s closure, author use the Ram Theory and Helmholtz theory to calculate the runner length and diameter as well as total distance traveled by the pressure column during the intake valve closure. To find out the pressure variation in cylinder runner due to intake valve opening and closing, author design virtual engine of the same specification of Kawasaki Ninja ZX-6R by using leading engine designing software “Ricardo Wave”, and then use these pressure data to develop the transient boundary condition in “Ansys Fluent”. To achieve the static pressure inside the plenum and distribute the combustible air evenly to each intake runner, author select two design variables; plenum shape (rectangular, circular, elliptical and curved) and plenum size (2.0litre, 2.25litre, 2.5litre, 2.75litre and 3.0litre). To find the best result for plenum, author perform the experiment in Ansys Fluent for all possible experiment and find the curved and elliptical shape plenum were providing higher volumetric efficiency, static plenum pressure and even flow of distribution to each cylinder. For designing final intake manifold author select the best design from all three part; restrictor, cylinder runner, plenum; and perform the experiment using computational fluid dynamics software Ansys Fluent, and in result he find that plenum with 2.5litre size curved shape with restrictor of 48mm nozzle inlet diameter, 41mm inlet curvature radius, 152mm diffuser length, and 30and 70 diffuser half angle. Keywords: Intake Manifold, Plenum, Restrictor, Cylinder Runner, Volumetric Efficiency, Computational Fluid Dynamics