Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established.
Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed.
Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber.
Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.