Temperature Field Mathematical Modeling And Numerical Simulation System For Rotary Kiln Of Oxidized Pellet

The production of oxidized pellets is an important part of steel production.Rotary kiln is a thermal equipment for processing oxidized pellets,and its pellet production process has become mature,but it is equipment-closed and involves many production parameters.It is very important to master the temperature distribution and the relationship of parameters in it.In order to realize the internal visualization of equipment and the intelligence of the production process,it is necessary to combine computer technology and other technologies to research the temperature field of the equipment,so that the production of oxidized pellets can be guided.In this paper,the structure of the rotary kiln for oxidized pellet and the working process is analyzed.According to the heat transfer object,the heat transfer process in the rotary kiln and the surrounding environment of the rotary kiln is described in detail.On the basis of reasonably simplifying the equipment structure,physical and chemical reactions and heat transfer process,using mathematical modeling method,and considering the complex heat transfer phenomenon in the contact part between the material and the kiln wall,a mathematical model of heat transfer of the rotary kiln is established,which includes the conduction heat transfer sub-model,the radiation heat transfer sub-model and the convection heat transfer sub-model.Model-dependent heat transfer coefficients are calculated.The mathematical model of heat transfer is solved by the classical Newton method.The model was verified by using the data provided by the production site of a pelletizing plant,and the error of model is within 15%.On the basis of the mathematical model,a computer model is established by using MATLAB.Taking the temperature distribution of gas,material and kiln’s outer wall as the objects,based on graphical user interface,a simulation system of temperature field of rotary kiln is designed.Functions such as displaying of rotary kiln temperature field and saving parameters and temperature data are realized.Based on the mathematical model of heat transfer in rotary kiln and temperature field simulation system,the effects of clean air,coal air,secondary air and rotary kiln’s rotation speed on the temperature field were studied.Among them,the length of flame,flame’s root and combustion zone are negatively correlated,positively correlated and negatively correlated with the volume flow of the clean air,respectively,and all positively correlated with the mass flow of the coal;the increase of the rotary kiln’s rotation speed and the volume flow of the secondary air will reduce the overall temperature of the rotary kiln.