Diseño de un plenum de admisión para un motor de combustión por hidrógeno, fundamentado en criterios geométricos en búsqueda de una mejor eficiencia volumétrica

Abstract

This research evaluated the fluid dynamic behavior of three intake plenum configurations for a Honda GX200 engine (original design, Venturi-type design, and Bellmouth-type design), with the aim of identifying the geometry with the best performance for guiding airflow toward the cylinder head, reducing pressure losses, and improving volumetric efficiency. The methodology combined experimental measurements and CFD numerical simulation: during the experimental phase, engine speed, intake vacuum, temperature, and mass flow were recorded under three operating conditions (idle, medium load, and high load), and these data were used to define the boundary conditions of the numerical model developed in ANSYS Fluent using the k-omega SST turbulence model, whose reliability was supported through solver convergence criteria and mesh independence analysis. The results showed that plenum geometry directly influences velocity distribution and pressure drop in the intake system; the original design exhibited the least favorable behavior due to abrupt geometric transitions and a greater tendency toward internal losses, the Venturi-type design improved flow guidance compared to the original but showed localized accelerations and less favorable pressure recovery, whereas the Bellmouth-type design achieved the best overall performance by providing a more progressive inlet, better flow uniformity, and lower aerodynamic restriction. The experimental comparison between the original plenum and the Bellmouth plenum confirmed this trend, with increases in mass flow and engine speed under the same vacuum conditions, as well as more stable engine operation, leading to the conclusion that the Bellmouth-type plenum is the most technically suitable alternative for optimizing the intake system of the evaluated engine.