Biomimetic swirl device and hydrogen enrichment effects on LPG fueled engine

Inspired by the humpback-whale flipper which enables robust aerodynamic force production, we propose a biomimetic blade design for small Biomimetic Swirl Device (BSD) added on gaseous engine inlet system. Such system can achieve robustness in aerodynamic performance for the intake flow. Therefore, the BSD design has an important impact on swirl generation inside the engine cylinder which its geometry was defined by a wavelength, leading edge radius and amplitude. For this reason, a numerical analysis method, by means a computational fluid dynamics 3D modeling technique, was utilized to study the in-cylinder flow characteristics investigating the optimal BSD geometry. Moreover, the effect of Hydrogen on in-cylinder flow characteristics of liquefied petroleum gas (LPG) bi-fuel engine has been examined using the BSD. In this research, five designs of the BSD with the dimensionless amplitude A* varied at 0.08, 0.12, 0.16, 0.2 and 0.24 were compared with the model without BSD to investigate its effect on the air-LPG flow inside the combustion chamber. The results showed that the BSD with A* = 0.2 created more turbulence, in-cylinder velocity, swirl in the combustion chamber than the other designs. Simulation results indicated also that LPG-30% H2 blend with BSD added gives the optimal in-cylinder flow characteristics of the TKE, the velocity and the swirl ratio.