Numerical Simulation Study Of Clinker Movement In Gas-solid Heat Exchange Environment

Cement clinker is a product in the process of cement preparation,and its temperature is higher and reduced to a certain range by the cooling and conveying of the grate cooler.The research on heat transfer of high-temperature clinker is still in the stage of establishing static heat transfer models,which are not consistent with the flow state of clinker.Cement clinker has the dual properties of fluid and solid.Discrete element method is an ideal method to study the flow characteristics of this material.During the transportation process,the high-temperature cement clinker and the low-temperature air exchange heat.The CFD method can describe this gas-solid heat exchange.When the discrete clinker particles exchange heat with the air,it is more reasonable to combine the discrete element method and computational fluid dynamics method to conduct heat exchange research.This paper intends to explore the feasibility of using CFD-DEM coupling method to simulate the heat transfer of clinker flow in gas-solid two-phase environment,and provide the physical property parameters of cement clinker necessary for the adoption of this method,as well as the solutions to the problems encountered in the research process.Firstly,the clinker accumulation body model is established.The accumulation model is the initial state of the moving material bed,so a collection experiment is designed for the structural parameters of the accumulation body.The slicing method is used to obtain the slicing image of the accumulation body,and then the size calibration and binarization processing are carried out on the slicing image to obtain the relevant structural parameters of the clinker particles in the stacking body.In addition,in order to reconstruct the accumulation of clinker,the NARX neural network is used to train the accumulation prediction model,and the correlation of the model is verified.Secondly,the results of discrete element simulation and particle flow experiment are compared.In order to implement the discrete element simulation,the physical properties of the experiment materials are firstly calibrated,and then the angular velocity of the particles is obtained by the discrete element simulation.Then a clinker flow experiment bed is designed based on the industrial grate cooler and the attitude sensor is used to collect the angular velocity of clinker particles.Finally,the applicability of the discrete element method to describe the flow characteristics of cement clinker is verified by comparing the angular velocity of particles that characterizes the intensity of clinker flow and heat transfer.Finally,the results of the clinker flow heat transfer experiment and CFD-DEM simulation are compared.Based on the heat exchange principle of the grate cooler,a clinker flow heat transfer experiment bench is developed,and the flow heat transfer experiment is carried out using this platform.The experimental conditions are used as the boundary conditions of the simulation,and then the CFD-DEM coupling method is used to simulate the heat transfer under the clinker flow conditions.The simulation and experimental results are compared to verify the applicability of the coupling method to the flow and heat transfer of clinker.