Study Of Heat Transfer Law Of Clinker Deposit In The Grate Cooler Based On The LBM

The grate cooler in the cement production process has a role in cement clinker transport and cooling.In order to improve the cooling effect and the heat recovery rate,the study of heat transfer law of clinker deposit in the grate cooler is the basis.So far,the study of heat transfer law is based mainly on two methods: one based on the theory of gas-solid heat transfer,another method based on the seepage heat transfer theory of porous media.Both methods ignore the effect of porous media pore boundaries on heat transfer,and can't satisfy both the precision and convenience.So this paper introduces the LBM into the study of heat transfer law of clinker deposit for the first time,and puts forward a new research method.On this basis,a reasonable air supply scheme is given to enhance the cooling effect and heat recovery rate,and to achieve the goal of saving energy.First of all,the unit model is established.According to the size of the feature unit,the porosity,the cross-sectional average diameter of cement clinker particle,and the isotropy of the unit,a two-dimensional physical model of the unit is established.A mathematical model of the unit is based on a coupled double distribution function lattice Boltzmann model which is put forward by Li Q used for compressible flow.Secondly,we get the heat transfer law of the unit by MATLAB.In order to facilitate heat transfer law of the unit extended to the whole clinker layer,and greatly reduce the amount of calculation,we get a total of 26 curves of heat transfer law under 26 values of clinker particles temperature.Each curve includes independent variables of inlet air velocity and temperature,and includes dependent variable of outlet air temperature.Thirdly,we get the heat transfer law of the whole clinker layer.We get the temperature distribution of the whole clinker layer and the air temperature at the layer outlet by a two-layer nested loop algorithm.Then,the new method is verified by experiments.We measure the clinker temperature at the layer inlet,the air and clinker temperature at the layer outlet by experiment device devised by ourselves.It is found that the maximum error between experimental data and theory data is below 8%.So the experimental data and theory dataare compatible basically.Finally,a reasonable air supply scheme under a certain working condition is given to enhance the cooling effect and heat recovery rate.The scheme increases the heat recovery rate to 85%.