Heat Transfer Analysis Of Blast Furnace Hearth Cooling Stave

The lifetime of blast furnace has already been an important indicator for measuring the technology of puddling.Water pipe is placed in the noumenon of cooling stave.When the cooling stave is in work,the convective heat transfer between water and pipe wall can take away the heat.This process of conduct heat can also lower the temperatures of the brasque and the furmace shell,guarantee the structural strength of the brasque and the furnace shell.In this paper,the cooling equipment(cast iron cooling stave)which is widely used in steel mills is used as an example model to complete the heat transfer analysis.In the heat transfer process of the cooling stave,the heat convection between the water and the pipe did most of the work.Usually we use the empirical formula to calculate the coefficient of convective heat transfer.We can also pull the expression of coefficient of convective heat transfer by using the correlation of criterion number.In the same velocity of water,we get different results of convective heat transfer coefficient by using these two methods.The difference between the two results is almost one order of magnitude.By observing the operating condition of blast furnace hearth,we find the empirical formula is reliable,but the correlation of criterion number also has theoretical basis.In the writer's opinion,the reasons for this phenomenon are as follows:In the processing of cooling stave,we paint anti-carburizing paint on the water pipe in order to secure the pipe not to be damaged by melted iron.In addition,there is an air gap between the pipe and the cooling stave.The thermal resistance of these two parts is very high.We think we have considered the attenuation effect of the thermal resistance when we calculate the coefficient of convective heat transfer by using the empirical formula.In this paper,the writer apply the finite element analysis software——ANSYS to analyze the heat transfer of cast iron cooling stave of blast furnace which is under steady-state.We use the results of the analysis to prove the writer's opinion is vindicated.During the using of the blast furnace,the velocity of the water isn't always at high speed.But the empirical formula obviously does not work in the state of low speed.In this paper,the writer use the parameter of cast iron cooling stave and the correlation of criterion number to derive the expression of the coefficient of convective heat transfer which are in different situations(laminar flow,transition flow,turbulent flow),and then deduce the comprehensive heat transfer expression of laminar conditions(considering the attenuation thermal resistance).And the writer use the FLUENT(a simulation software)to simulate the running situation of blast furnace.I can prove the expressions are reliable by using the results of the analyses.The comprehensive heat transfer expression of laminar conditions downsize the scale of the heat transfer model,and it can also simplify the boundary treatment.