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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]

The methanol and turbulent jet ignition (TJI) mode were used simultaneously to improve the combustion and emission performance of a gasoline rotary engine (RE) in the study. Further, the experimental bench and numerical model of the TJI-RE fueled with methanol/gasoline blends were established respectively. The reliability of the numerical model was verified by the experiments. Eventually, based on the numerical model, the effects of jet orifice angle (JOA) and jet orifice position (JOP) on the in-cylinder combustion were studied. The results showed that for both the JOA and JOP, they affected the combustion of the TJI-RE through the impingement point of the jet flame on the rotor piston wall and the intensity of the vortex formed by impingement of jet flame on rotor piston wall. For engineering applications, the JOA is recommended to be −30°, and the JOP is recommended to be 16.5 mm on the left side of the vertical axis of the cylinder. Under the above case, compared with the case who has the JOA of +30° and the JOP of 5.5 mm on the right side of the vertical axis of the cylinder, the peak pressure is increased by 32.8%, and the indicated thermal efficiency is increased by 10.26%. • Methanol was used in traditional gasoline rotary engines to reduce carbon emissions. • The turbulent jet ignition (TJI) was used to improve the combustion performance of rotary engine. • The test bench and the numerical simulation model of the TJI rotary engine were established. • The effects of jet orifice angle (JOA) and jet orifice position (JOP) on the combustion were studied. • The JOA was recommended to be −30°. • The JOP was recommended to be 16.5 mm on the left side of the vertical axis of the cylinder. [ABSTRACT FROM AUTHOR]