In this paper a commercial CFD （computational fluid dynamics） code FLUENT has been used and modified for the axisymmetric swirl and time-dependent simulation of an atmospheric pressure argon arc in an external axial...In this paper a commercial CFD （computational fluid dynamics） code FLUENT has been used and modified for the axisymmetric swirl and time-dependent simulation of an atmospheric pressure argon arc in an external axial magnetic field （AMF）. The computational domain includes the arc itself and the anodic region. Numerical results demonstrate that the AMF substantially increases the tangential component of the plasma velocity. The resulting centrifugal force for the plasma rotation impels it to travel to the arc mantel and as a result, a low-pressure region appears at the arc core. With the AMF, the arc presents a hollow bell shape and correspondingly, the maximal values of the temperature, pressure and current density on the anode surface are departing from the arc centreline.展开更多
A theoretical model is presented to describe the electromagnetic, heat transfer and fluid flow phenomena within a magnetron plasma torch and in the resultant plume, by using a commercial computational fluid dynamics ...A theoretical model is presented to describe the electromagnetic, heat transfer and fluid flow phenomena within a magnetron plasma torch and in the resultant plume, by using a commercial computational fluid dynamics （CFD） code FLUENT. Specific calculations are pre- sented for a pure argon system （i.e., an argon plasma discharging into an argon environment）, operated in a turbulent mode. An important finding of this work is that the external axial magnetic field （AMF） may have a significant effect on the behavior of arc plasma and thus affects the resulting plume. The AMF impels the plasma to retract axially and expand radially. As a result, the plasma intensity distribution on the cross section of torch seems to be more uniform. Numerical results also show that with AMF, the highest plasma temperature decreases and the anode arc root moves upstream significantly, while the current density distribution at the anode is more concentrated with a higher peak value. In addition, the use of AMF then induces a strong backflow at the torch spout and its magnitude increases with the AMF strength but decreases with the inlet gas velocity.展开更多
The gliding arc is an important approach to production of non-thermal plasma at atmospheric pressure, it can offer high-energy efficiency and high-electivity for chemical reactions. In this paper, the gliding arc driv...The gliding arc is an important approach to production of non-thermal plasma at atmospheric pressure, it can offer high-energy efficiency and high-electivity for chemical reactions. In this paper, the gliding arc driven by the transverse magnetic field is described and its velocity is measured by using a photo-multiplier. The mean velocity of the gliding arc increases with increasing magnetic induced-intensity, and its value varies from 7.8 m/s to 32 m/s.展开更多
A commercial CFD （computational fluid dynamics） code FLUENT was used and modified to model an atmospheric pressure argon arc in a low cross flow by solving the fully coupled conservation equations. Numerical experim...A commercial CFD （computational fluid dynamics） code FLUENT was used and modified to model an atmospheric pressure argon arc in a low cross flow by solving the fully coupled conservation equations. Numerical experiments, with an arc current of 100 A to 200 A, an arcing distance of 3 mm to 6 mm, and a cross-flow velocity of 10 m/s to 30 m/s, were carried out. The modelling results show that the arc tends to take the shortest path to the anode when deflected by the cross flow; its anode attachment is farther downstream than the cathode one. Furthermore, due to the low input gas flow imposed in this study, the effect of electromagnetic force is important and it influences the crosscut shape of the arc significantly.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10375065 and 10675122)
文摘In this paper a commercial CFD （computational fluid dynamics） code FLUENT has been used and modified for the axisymmetric swirl and time-dependent simulation of an atmospheric pressure argon arc in an external axial magnetic field （AMF）. The computational domain includes the arc itself and the anodic region. Numerical results demonstrate that the AMF substantially increases the tangential component of the plasma velocity. The resulting centrifugal force for the plasma rotation impels it to travel to the arc mantel and as a result, a low-pressure region appears at the arc core. With the AMF, the arc presents a hollow bell shape and correspondingly, the maximal values of the temperature, pressure and current density on the anode surface are departing from the arc centreline.
基金National Natural Science Foundation of China(Nos.10375065,10675122)
文摘A theoretical model is presented to describe the electromagnetic, heat transfer and fluid flow phenomena within a magnetron plasma torch and in the resultant plume, by using a commercial computational fluid dynamics （CFD） code FLUENT. Specific calculations are pre- sented for a pure argon system （i.e., an argon plasma discharging into an argon environment）, operated in a turbulent mode. An important finding of this work is that the external axial magnetic field （AMF） may have a significant effect on the behavior of arc plasma and thus affects the resulting plume. The AMF impels the plasma to retract axially and expand radially. As a result, the plasma intensity distribution on the cross section of torch seems to be more uniform. Numerical results also show that with AMF, the highest plasma temperature decreases and the anode arc root moves upstream significantly, while the current density distribution at the anode is more concentrated with a higher peak value. In addition, the use of AMF then induces a strong backflow at the torch spout and its magnitude increases with the AMF strength but decreases with the inlet gas velocity.
文摘The gliding arc is an important approach to production of non-thermal plasma at atmospheric pressure, it can offer high-energy efficiency and high-electivity for chemical reactions. In this paper, the gliding arc driven by the transverse magnetic field is described and its velocity is measured by using a photo-multiplier. The mean velocity of the gliding arc increases with increasing magnetic induced-intensity, and its value varies from 7.8 m/s to 32 m/s.
基金supported by National Natural Science Foundation of China (Nos.10375065,10675122)
文摘A commercial CFD （computational fluid dynamics） code FLUENT was used and modified to model an atmospheric pressure argon arc in a low cross flow by solving the fully coupled conservation equations. Numerical experiments, with an arc current of 100 A to 200 A, an arcing distance of 3 mm to 6 mm, and a cross-flow velocity of 10 m/s to 30 m/s, were carried out. The modelling results show that the arc tends to take the shortest path to the anode when deflected by the cross flow; its anode attachment is farther downstream than the cathode one. Furthermore, due to the low input gas flow imposed in this study, the effect of electromagnetic force is important and it influences the crosscut shape of the arc significantly.
