Analysis Of Open Heat Transfer Characteristics And Calculation Of Thermal Stress Of Blast Furnace

Blast furnace is an important equipment for steel production.The life of the blast furnace has become an important index to measure the progress of iron making technology.Domestic and foreign surveys show that the erosion of the ovens and hearth of new or overhauled blast furnace is the main factor affecting the life of blast furnace.The current oven system generally draw on the past similar lining structure,similar volume blast furnace experience,whether it is difficult to determine whether the application;In addition,in the past,the heat transfer analysis of blast furnace hearth,in order to simplify the calculation of ramming material thermal properties and mechanics The performance is taken as a fixed value,and the calculation of forced convection heat transfer coefficient in the pipe is mostly used empirical formula,resulting in lower accuracy of the calculation results.In order to make the calculation more accurate,The correlations with the temperature are obtained by experiment.The formulas of the convective heat transfer coefficients in water pipes under different water velocities are deduced by using the quasi-correlation formula.The blast furnace hearth model was established by ANSYS finite element software and its steady state and transient thermal analysis were carried out.On the basis of previous thermal analysis of the ovens,thermo-structure coupling analysis was carried out on the side wall of the blast furnace hearth,The effect of furnace pressure on the thermal stress characteristics of the hearth structure and the verification of the furnace shell strength are as follows(1)Through the experimental results,the differences of thermal conductivity,linear expansion coefficient and compressive strength between asphalt combined ramming compound and resin combined ramming compound were obtained,and the relationship between them was also obtained.Coefficient,coefficient of linear expansion and compressive strength with temperature correlation.The relationship between thermal properties and mechanical properties of ramming mix and the thermal stress of blast furnace liner is discussed in theory,providing a theoretical basis for designing long life of blast furnace.(2)Combined with convective heat transfer theory,the expression of forced convection heat transfer coefficient in tube under different water velocities(laminar flow,transient flow and turbulent flow)is derived by using the quasi-correlation formula.The equivalent thermalresistance theory Wall air gap were replaced by equivalent,the side wall model of blast furnace hearth was established by ANSYS software,and the conditions of quasi-correlation and empirical formula method were validated by comparing the heat flux value of hot spot of inner packings.(3)The side wall oven model of blast furnace hearth and hearth was established,the temperature limit of the furnace was determined,and the steady state and transient thermal analysis of the side wall of the hearth were carried out.The effects of different cooling water velocities,outside air temperature,The influence of the hearth oven,the model of the central part of the hearth,the temperature change of the filler layer under different cooling water velocities were analyzed.This method of analysis of the hearth oven heat transfer analysis has a certain versatility,the initial development of the oven system can be assessed and improved.(4)Based on the thermo-mechanical theory of the hearth,based on the thermal analysis of the hearth,an indirect coupling method was used to analyze the heat-structure coupling of the hearth,and the influence of the temperature of the molten iron and the pressure inside the furnace on the stress characteristics of the hearth The furnace shell strength was checked.