Study On The Radiative Properties Of Soot Particles In The Coal Of Combustion

According to the actual combustion process in the apparatus, Soot particlescomprise a large share of particulate matter which is discharged. The combustion flameheat is mainly through radiation transfer, but the excessive amount of soot particlesproduction will lead water cooled wall to be slugging. And soot particles that are emittedinto the atmosphere are easily pollute the environment, trigger respiratory diseases andendanger the human health. Actual soot particles model are not spherical model of singleparticle, and they will be further gathered to become soot aggregates. The radiativeproperties of soot aggregates will affect the accurate calculation of the radiation heattransfer and accurate simulation of the flame temperature diagnostic. Therefore, it hasimportant significance to study on the radiative properties of soot particles in strengtheningradiation transfer heat in the furnace, reducing pollution and protecting human health.In the present thesis, the formation mechanism and light scattering properties ofsoot particles are described, and it is mainly introduced that Mie scattering theory,Generalized Multi-particle Mie-solution and T-matrix method from electromagnetic theory.Then, the program of Mie scattering theory can be used to calculate the radiative propertiesof single soot particle and the calculation indicates that the more or less of radius of singlesoot particle influences its radiative properties. The fractal conception that is proposed iscombined with growth model to simulate the process of soot particles gathering to beaggregates. Generalized Multi-particle Mie-solution is used to calculate the radiativeproperties of gathering particles which consists of two particles and then it is discussed thatindependent scattering during the two particles through changing the distance between them.And the data indicates that independent scattering can be ignored when the distancebetween two particles is far to some degree.T-matrix method can be used to calculate the radiative properties of soot aggregatesand it is discussed that the fractional dimension, the proposal factor and the amount of particles separately of soot aggregates how to affect. The calculation indicates that both ofthe fractional dimension and proposal factor make the structure of soot aggregates becomegradually shrink to the center of mass of soot particles from the original loose shape ifkeeping the amount of soot particles unchanged. However, it is obtained that thefractional dimension plays a more important role in enhancing radiation transfer heat basedon comparing with the proposal factor. And when the amount of soot particles becomesmore, it leads that more particles take part in radiation transfer and the radiation transferheat of the whole of soot aggregates enhances much more.