| Heat treatment furnace is the main equipment for heat treatment process in metallurgical industry,and the temperature uniformity inside the furnace chamber is one of the important indicators for judging the merits of heat treatment furnace.In view of the problem that the local temperature of a trolley type heat treatment furnace of special steel production enterprise is too high to ensure the requirements of the special steel production process,a plan to improve the furnace temperature uniformity by optimizing the structure and arrangement of the combustion device is proposed.In this paper,the rationality of the optimization scheme of the combustion system is investigated by numerical simulation and experimental verification,the details and findings of the study are as follows:1)The physical model required for the numerical simulation was established for a bogie-type heat treatment furnace of a special steel manufacturer,and the distribution laws of the flow and temperature fields in the furnace were studied by using Fluent 2022 simulation software,in which the standard k-ε dual equation model was used for the turbulence model,the general finite rate model was used for the combustion model,and the P1 model was used for the radiation model.The results show that the maximum temperature deviation in the effective heating area of the furnace chamber is 136 K.The main reason for the high local temperature in the furnace chamber is the insufficient intensity of the flame ejected from the combustion device and the small radiation range.2)The effects of these two factors on the flame intensity and radiation range were investigated by adjusting burner block necking angle in the combustion system and the spacing of the combustion device arrangement.The research results show that the flame intensity increases with the increase of the indentation angle of the burner brick,and when the necking angle of the burner brick is 18°,the exit velocity of the combustion device increases and the flame intensity is enhanced,which makes the flame intensity and the gravitational force of the negative pressure zone reach a balance,the furnace temperature uniformity reaches the best,and the maximum temperature difference of the effective heating area in the furnace chamber is 95 K;The flame radiation range is enhanced with the increase of the ratio between the spacing of combustion devices and the length of the furnace chamber.When the ratio reaches a maximum of 12.5%,the mutual influence of adjacent combustion devices is weakened,the flame radiation range is enhanced,the furnace temperature uniformity reaches the best,and the maximum temperature difference of the effective heating area in the furnace chamber is 14 K.3)Combined with the results of the simulation and optimization of the structure and layout of the combustion device of the trolley type heat treatment furnace,the on-site heat treatment furnace was optimized and modified,and tested according to "GB/T 30824-2014 Gas Heat Treatment Furnace Temperature Uniformity Test Method".Through the furnace temperature uniformity test in the effective area of the furnace chamber,the following conclusions were drawn: the maximum positive deviation of the temperature measured in the two insulation stages was +8.4 K,and the maximum negative deviation of the temperature was-7.9 K,which satisfied the temperature uniformity requirements of the Class III heat treatment furnace,and the temperature distribution was basically consistent with the simulation analysis results,which verified the reliability of the numerical simulation of the simulation model.In this paper,the structure and layout of the combustion device of the trolley type heat treatment furnace are optimized to weaken the local high temperature in the furnace and improve the uniformity of the furnace temperature,and the research results provide certain solutions and theoretical basis for the technical transformation and upgrading of the heat treatment furnace. |
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