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The aim of this work is to enhance the combustion performance of a turbulent jet ignition Wankel rotary engine (TJI-WRE) fueled by hydrogen/natural gas blends (HNGB) by changing the cylinder shape and adding a turbulence blade (TB). Therefore, the test bench and numerical simulation model for the TJI-WRE are established. Further, the flow field and flame propagation of the TJI-WRE with various cylinder shapes and turbulence blades are investigated. The results demonstrate that a new vortex is formed after the jet flame is injected into the cylinder and impacts the rotor piston surface. This vortex can enhance the combustion speed of the mixture in the back of the cylinder (BOC). The cylinder shape can change the intensity of the new vortex by changing the distance between the jet orifice and the piston surface. Furthermore, TB can change the combustion process by squeezing the in-cylinder unidirectional flow in the combustion stroke. Since the flame mainly propagates to the front of the cylinder (FOC) at the initial combustion stroke, as the TB layout moves from the BOC to the FOC, the squeezing effect of TB on the flame in the FOC becomes increasingly significant, resulting in increased combustion efficiency in the cylinder. [Display omitted] • Hydrogen/natural gas blends fuel was used to reduce carbon emissions. • A computational model of the turbulent jet ignition rotary engine was established. • The mixture formation, combustion, and emissions process were analyzed. • The optimal combination of cylinder structure for the rotary engine was given. • Compared with the original model, optimal cylinder structure PVIP increased by 12.6%. [ABSTRACT FROM AUTHOR]

The rapid development of electric vehicles has drawn extensive attention to using rotary engines as small-scale power generation devices. However, their wide application has been limited by drawbacks such as low combustion efficiency and high emissions. Therefore, to obtain rotary engines with high combustion efficiency and low emissions, this study explored the strengthening effect of natural gas/hydrogen hybrid fuel (NHHF) and Triangular Rotor Piston (TRP) structure on the combustion in the turbulent jet ignition rotary engine (TJI-RE) at different ignition advance angles (IAAs). Additionally, an experimental platform and a three-dimensional computational model for TJI-RE fueled by natural gas/hydrogen hybrid fuel (NHHF) were established in this study. The research results indicated that the TRP structure altered the combustion process by affecting the ignition area in the ignition stage and the turbulence kinetic energy during the combustion stroke. Furthermore, the SC-shaped cylinder exhibited the highest peak pressure for any fixed IAA. When the IAA was fixed at 30°CA (BTDC), the TJI-RE with the SC-shaped cylinder experienced a 12.12% increase in peak pressure and a 4.1% increase in indicated work compared to the FP-shaped cylinder. Additionally, the CO emission was reduced by 13.79%, while the NO emission showed a significant increase. • NHHF was used to reduce the carbon emissions of the RE. • A three-dimensional computational model of the TJI-RE was established. • The effect of piston structure on combustion in TJI-RE was systematically studied. • The optimal combination of piston structure and IAA for the TJI-RE was given. [ABSTRACT FROM AUTHOR]