شبيه سازي انتقال حرارت در كوره هاي قوس الكتريك جريان مستقيم

چكيده انگليسي :

Simulation of Heat Transfer in Direct Current Electric Arc Furnace Amirbahador mashhadi a mashhadigholamali@me iut ac ir May 8 2011 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Ahmad Saboonchi Prof ahmadsab@cc iut ac irAbstractIn this research a mathematical model was developed to describe fluid flow heat transfer and electromagneticphenomena in the bath region of a Direct Current Electric Arc Furnace DC EAF The different effects on the steelbath from the arc a layer of slag on the top of the steel and the injection of argon gas from the bottom arerepresented using three different numeric approaches and analyzed in terms of fluid flow heat transfer andtemperature stratification in the steel bath Additionally a sensitivity analysis was performed to explore the effect ofthe main process parameters and design variables of the process such as furnace dimensions arc conditions andanode configurations In the recent years using electric arc furnaces for steel making had an salient increase Vastutilization of electric energy for metal melting instead of old fuels shows an necessity in investigating in this field Direct current electric arc furnaces are kind of steelmaking equipments which have more benefits in differentindustries comparing with alternative current AC electric arc furnaces and consequently using them is in growth inindustry Metal refining stage in steel making process is so significant because in this stage molten bath heating in asteady state process will resume until the melt under influence of heat and jet momentum which conducted byelectric arc become more homogenized and distribution of temperature field become smoother Effectiveparameters in bath mixing in direct current electric arc furnace can be counted as buoyancy force Lorentz forceand momentum jet of direct current electric arc Effect of each one of these parameters in bath circulation isinvestigated and by a simultaneously solving of momentum energy and electromagnetic equation in Fluent withauxiliary module of magneto hydro dynamics MHD and writing specific codes in Fluent for introducingelectromagnetic force and distribution of heat flux and shear stress which knows as User Defined Function UDF fluid flow pattern will be recognized This pattern shows that near the furnace axis molten bath has acounter clockwise motion which happens under the influence of electromagnetic force and current densitydistribution close to axis At the points close to side walls of furnace due to the reduction in electromagnetic fieldeffect and domination of buoyancy force bath circulation is changed and shows a clockwise circulation There islots of parameters such as total amperage of arc electric arc length and foamy slag practice which affect on bathmixing phenomena and temperature field Changing amount of total amperage in a constant length of arc from 36KA to 40 44 and 50 KA shows that values of average temperature increase This happens because of growth inamount of energy transferred to molten bath and flow pattern face with changes in 40KA and 25cm arc lengthcomparing with 36KA This is because of increasing in current density passing through the bath causingelectromagnetic force dominate in bath circulation and buoyancy effect lessen in bath circulation Changing inelectric arc length from 20cm to 25 and 30cm shows an increase in average temperature of melt which is due to thegrowth in amount of energy transferred to the baht Comparing these results with other results in other researchshows a good agreement Slag effect impresses the average temperature of bath by increasing it about 30 35 degreewhich buoyancy effect was dominant Key words direct current electric arc furnace bath circulation electromagnetic hydrodynamics

مشهدي، اميربهادر

شبيه سازي انتقال حرارت در كوره هاي قوس الكتريك جريان مستقيم

حركت مذاب , هيدروديناميك مغناطيسي