Numerical analysis of coal water mixture combustion in double cone reversed injection burner

In order to study the differences between the combustion processes in double cone reversed injection burner of coal particle and coal water mixture,numerical simulation model of 14 MW reversed injection burner was built based on CFD software Fluent. The results show that the velocity fields of coal particle and coal water mixture are basically similar.The vaporization of water in the coal water mixture increases the resistance of the burner and the residence time of the discrete phase particles in the combustor.Due to the high moisture content,the ignition position of coal water mixture is lagged by 110 mm,compared with coal particle.The average temperature and outlet temperature in the burner with coal slurry are reduced by 162 K and 199 K,respectively,compared with that of coal particle.The core temperature zone of the coal water mixture torch is 438 mm ahead of the coal particle.And the rigidity of the coal water mixture troch is stronger than that of the coal particle.But the decay rare of the coal water mixture torch is faster than the coal particle's.The combustion characteristics of coal water mixture are in the effective range of the combustion control of reversed injection burner.It is proved that the optimization of combustion principle is one of the effective methods to solve the contradiction between the combustion temperature and efficiency of coal water mixture.