Numerical Simulation of Flow and Emission Characteristics in Hydrogen-blended Combustion of Gas Turbines

In response to China's "dual carbon" strategy, hydrogen-blended combustion technology for gas turbines has become an important development direction. Based on the SST k-ω turbulence model and a non-premixed combustion model, the flow and emission characteristics of hydrogen-blended natural gas in a can-type combustor were numerically investigated under fuel inlet velocities ranging from 40 to 120 m/s and hydrogen blending ratios from 0 to 20%. Results show that for both pure natural gas and the 20% hydrogen-blended cases, the combustor outlet temperature peaks at 100 m/s before declining. When the inlet velocity exceeds 100 m/s, the hydrogen-blended cases exhibit higher outlet temperatures and a more uniform temperature distribution. However, the high velocity disrupts the recirculation zone and reduces combustion efficiency. CO emissions increase linearly while CO₂ emissions first rise and then decrease. A comprehensive analysis identifies the optimal fuel inlet velocity as 80 m/s. Under this operating condition, compared to pure natural gas combustion, blending 20% hydrogen expands the recirculation zone area and extends the residence time for complete fuel combustion. Consequently,CO₂ and CO emissions decrease by 14.8% and 54.9%, alongside a 64.1% increase in NO_x emissions and an elevated risk of combustion instability. This research provides important theoretical support for optimizing hydrogen-blended combustion systems in gas turbines.