Análisis numérico del chorro compresible de hidrógeno en una cámara de volumen constante

Abstract

This study presents a numerical analysis using Computational Fluid Dynamics (CFD) simulation to examine the behavior of a compressible hydrogen gas (H₂) jet injected into a constant-volume combustion chamber under conditions representative of a direct-injection internal combustion engine at the moment of ignition. The simulation was implemented in OpenFOAM 12 using a 2D axisymmetric 10° wedge domain, significantly reducing the computational cost compared to a full three-dimensional model. The multicomponentFluid solver was used with the k−ω SST turbulence model and the equations of conservation of mass, momentum, energy, and species transport for a nonreactive H₂–air mixture. The model was validated using experimental data from Delbari et al. (2025), yielding relative errors of 0.5% and −2.3% in the prediction of the jet’s axial penetration for the backpressure cases Pb = 0 kPa (g) (NPR = 7.69) and Pb = 150 kPa (g) (NPR = 3.10), respectively. The parametric analysis evaluated the effect of back pressure (2000, 3055, 3171, and 4000 kPa) and injection velocity (1051.6, 1314.5, and 1600 m/s) on axial penetration, radial dispersion, and flammability at the spark plug position (X = 44 mm). The results showed that increasing back pressure reduces axial penetration and promotes H₂ dilution, with a back pressure of 4000 kPa (NPR = 2.5) being the only condition with a fully flammable mixture at X = 44 mm. Meanwhile, variations in injection velocity demonstrated that higher velocities increase the radial dispersion of the jet but delay the axial availability of the flammable mixture at the spark plug position, indicating that both parameters must be optimized together to ensure effective ignition.