Numerical Simulation Of Combustion Process In The Cremator

Cremation is the main way of body disposal in China.However,the combustion situation of cremators is generally not ideal at present.It is necessary for controlling pollutant emissions and improving thermal efficiency.In this thesis,the actual cremation machine was used as the prototype,and inorganic small molecule fuel was used to replace remains.The combustion component model of the cremation machine was established,and the UDF program in FLUENT was used to write the definition.Based on the RANS control equations,by using the combustion component transport model and the standard k-? model,the combustion kinetics models for different combustion stages were established.The simulation results were in good agreement with the field test results,which verifies the reliability of the numerical simulation models.In order to explore the influence of combustion parameters on the combustion performance,the combustion process in the furnace was simulated with different excess air coefficient and preheating inlet temperature.The numerical simulation results showed that: with the increase of excess air coefficient from 1.05 to 1.17,the combustion time was shortened from 35 minutes to 30 minutes,the carbon monoxide emission first decreased and then increased,and the nitrogen oxide emission increased as a whole.With the increase of the preheating inlet temperature from 473 K to 573 K,the average concentration of carbon monoxide emissions increased,and the nitrogen oxide emissions did not change significantly.According to the general thermodynamic calculation method of the power plant boiler,the calculation method of thermal balance and entropy production in the furnace of the cremator was established.With the increase of preheating inlet temperature from 473 K to 573 K,the change of thermal efficiency was not obvious.Among all entropy production values,the output value of incomplete combustion entropy accounted for the largest proportion,which is much higher than that heat loss entropy production of smoke exhaust and ash residue.The research results of this thesis are helpful to further understand the unsteady combustion process in the furnace of the cremator,and provide necessary basis for the structure improvement,operation optimization,energy saving and emission reduction of the subsequent cremators.