This paper mainly investigates the effect of the premixing of hydrogen and gasoline (PHG) on the flow and combustion characteristics of the X-type rotary engine (XRE). The three-dimensional numerical simulation model is firstly established based on CFD software. Then, the flow fields and combustion performances of XRE under 1%, 3% and 5% energy fractions of hydrogen-blended (EFHB) are compared and analyzed. The results show that the in-cylinder mean turbulent kinetic energy (TKE) and vorticity present three peaks at the beginning, middle and end stage of the intake process, respectively. Meanwhile, the peak in the middle stage is the largest and steepest, indicating that the in-cylinder flow field is fully mixing air and fuel at this stage. The PHG can produce more OH, O and H radicals, and accelerate the combustion process. Furthermore, the PHG can increase the combustion temperature. In particular, the peak of the in-cylinder mean temperature is increased by 6.4% when the EFHB is 5%. The hydrogen can broaden the combustion area to both sides of the combustion chamber, and help to solve the problem of incomplete combustion in the slit of the combustion chamber of XRE.
Keywords X-type rotary engine, premixing of hydrogen and gasoline, flow field, combustion performance