Numerical Simulation Of Heat Transfer Characteristics In Blast Furnace Slag Particles Around Circular Tubes

There are abundant industrial waste heat resources in the production process,for example,electric power,steel,nonferrous metals and other industries.It is of great significance to recycle the waste heat.Blast furnace slag is produced as the main products of blast furnace ironmaking.It has high discharge temperature,which is a significant high-quality waste heat resources.Water quenching and air cooling are usually used to recover the blast furnace slag waste heat.This will not only generate harmful gases,but also consume a lot of resources and cause high costs.So the recovery of waste heat from high temperature slag particles is an important research.Disadvantages of recovering residual heat of high temperature slag particles by using air as cooling medium,this paper will use the self-flow bed waste heat boiler to directly recover the heat of high-temperature slag particles to produce hot water or steam.Study on the flow and heat transfer of high temperature slag particles in a self-flowing bed.In this paper,the commercial CFD software Fluent is used to simulate the flow and heat transfer process of high-temperature solid slag particles entering the heat exchanger.The research contents and results are as follows:(1)Without regard to air in the artesian bed,effects of slag particle diameters,inlet velocity of slag particle,inlet temperature of slag particle and row number of tubes on the heat transfer coefficient,outlet temperature and temperature drop rate in the heat exchanger were studied.Research indicates:As the slag particle diameter and the number of tube rows increase,the slag particle outlet temperature gradually decreases.As the slag particle inlet velocity and inlet temperature increase,the slag particle outlet temperature gradually increases.With the increase of the diameter of the slag particles,the temperature drop rate of the slag particles in the first row of heat exchange tubes gradually decreases.As the inlet velocity and temperature of the slag particles increase,the temperature drop rate of the slag particles in the first row of heat exchange tubes increases gradually increase.With the increase of the slag particle diameter,the heat transfer coefficient of the slag side gradually decreases.With the increase of the slag particle inlet velocity,the slag grain side heat transfer coefficient gradually increases.With the increase of the slag inlet temperature,the heat transfer coefficient is gradually increased.(2)Heat transfer characteristics under different air operating parameters were studied.Research indicates:Ventilation from different locations,the outlet temperature changes are obvious,ventilation at different locations has an impact on the overall heat transfer coefficient.Ventilation from the bottom,as the wind speed increases,the slag outlet temperature decreases,the air outlet temperature increases,and when the wind speed is 150～300mm/s,the overall heat transfer coefficient increases.(3)The local heat transfer effect of a single round tube around the slag is studied.Research indicates:When the slag particles flow around a single round pipe,the local heat transfer coefficient of the upper surface is large,and the local heat transfer coefficient is the smallest at the lower part of the round pipe.The influence of the wall effect has a certain influence on the heat transfer coefficient of the slag.