The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The vol...The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The voltage increases non-linearly with the increase of apparent plasma length, with the current fixed. The experimental data so obtained are compared with the predictions of the Bowman model for the electric arc, and with numerical simulations as well. The level of agreement between the experimental data at the melting anode and the numerical predictions confirms the suitability of the proposed the Bowman model. These characteristics are relevant to the engineering design and evaluation of a DC plasma furnace and reactor for the treatment of hazardous fly ash waste.展开更多
This paper presents a methodology for modeling and analysis of the interaction between two electromagnetic(EM)fields in a solidifying Ti-6A1-4V(Ti-6-4)ingot processed by the plasma arc cold hearth melting(PAM)process....This paper presents a methodology for modeling and analysis of the interaction between two electromagnetic(EM)fields in a solidifying Ti-6A1-4V(Ti-6-4)ingot processed by the plasma arc cold hearth melting(PAM)process. The two EM fields are generated by the induction coils(stirrer)around the ingot mold and by the plasma torch.This methodology is based on the numerical solution of Maxwell's equations,fluid flow,and heat transfer equations,and modeling of the grain structure.Numerical simulations at the macro-level were conducted using a CFD software.A stochastic model was developed and applied to simulate the grain structure at the mesoscopic level.Simulation results for 5-in and 8-in diameter Ti-6-4 ingots show that the plasma torch and the EM stirrer can have strong effects on both the fluid flow and the solidification structure.A comparison with an experimental grain structure of a 5-in diameter Ti-6-4 ingot is also provided.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 21171169)the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. O45CF3A211)
文摘The characteristics of a nitrogen arc using a graphite cathode and a melting anode in a pilot-scale plasma furnace are investigated. The voltage is examined as a function of current and apparent plasma length. The voltage increases non-linearly with the increase of apparent plasma length, with the current fixed. The experimental data so obtained are compared with the predictions of the Bowman model for the electric arc, and with numerical simulations as well. The level of agreement between the experimental data at the melting anode and the numerical predictions confirms the suitability of the proposed the Bowman model. These characteristics are relevant to the engineering design and evaluation of a DC plasma furnace and reactor for the treatment of hazardous fly ash waste.
文摘This paper presents a methodology for modeling and analysis of the interaction between two electromagnetic(EM)fields in a solidifying Ti-6A1-4V(Ti-6-4)ingot processed by the plasma arc cold hearth melting(PAM)process. The two EM fields are generated by the induction coils(stirrer)around the ingot mold and by the plasma torch.This methodology is based on the numerical solution of Maxwell's equations,fluid flow,and heat transfer equations,and modeling of the grain structure.Numerical simulations at the macro-level were conducted using a CFD software.A stochastic model was developed and applied to simulate the grain structure at the mesoscopic level.Simulation results for 5-in and 8-in diameter Ti-6-4 ingots show that the plasma torch and the EM stirrer can have strong effects on both the fluid flow and the solidification structure.A comparison with an experimental grain structure of a 5-in diameter Ti-6-4 ingot is also provided.
