Numerical simulation of the effects of protrusion on DC arc anode attachment

Niu, Chong; Meng, Xie; Huang, Heji

doi:10.1088/2058-6272/ac125e

Cited by 11 publications

(6 citation statements)

References 63 publications

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“…Lihua Zhao et al set a two-dimensional magnetohydrodynamic (MHD) model to simulate the arc movement between single-break transvers magnetic field contacts 8 . Niu et al established a 3D model to investigated that the deflection of arc was caused by protrusion on the anode surface 9 . Zixi Liu coupled fluid equation and electromagnetic field equation to grasp the parameter of plasma between contacts when the transverse magnetic field almost unchanged but the axial magnetic field decrease 10 .…”

Section: Introductionmentioning

confidence: 99%

Study of plasma-related parameters and self- generated TMF of contact under DB-DC VCB delayed breaking conditions

Yang,

Huang,

Shan

et al. 2024

Preprint

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Taking the mechanical double-break DC vacuum circuit breaker as the research object, the magnetic field and temperature field distribution between the breaks and the plasma characteristics under the working condition of gap difference caused by actuator dispersion are investigated to explore the difference of arc characteristics between the two breaks with different gaps. Based on the system of equations of Maxwell and magnetohydrodynamic (MHD) equations, a non-simultaneous breaking model of the DB DC VCB is established, and parameters such as magnetic flux density, plasma velocity, inter-contact pressure, and ion and electron temperatures are calculated. The simulation results show that the cathode surface field emission effect is stronger in the small gap break (delayed breaking break). Besides, in the small gap break, the arc temperature in is higher, the rate of decrease of temperature is lower, the electron velocity is higher, the magnetic flux density is lower, the regulatory ability of magnetic field is weaker, and the plasma diffusion speed is slower. In the arc ignition stage, the arc aggregation state duration of small gap break is longer than the normal break, and the arc transition time in small gap break is increased, which means the arc in small gap break get diffusion state later, and it is not conducive to the plasma diffusion and arc energy dissipation. Therefore, the arc energy density between delayed breaking break is greater, the arc morphology transition time is longer, the residual particle concentration after arc extinguishing is higher, and the probability of re-strike breakdown increases with the increase of gap difference. Improving the synchronization of the actuator could improving the breaking ability of DB DC VCB.

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Section: Introductionmentioning

confidence: 99%

Study of plasma-related parameters and self- generated TMF of contact under DB-DC VCB delayed breaking conditions

Yang,

Huang,

Shan

et al. 2024

Preprint

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“…The arc energy is transferred to the electrode through the sheath, which increases the electrode's surface temperature and alters the electron emission law of the cathode. [7][8][9] At present, there are two main microscopic mathematical descriptions of the sheath in highpressure arc discharge. The first is a unified description.…”

Section: Introductionmentioning

confidence: 99%

Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

Peng

Duan

et al. 2023

Chinese Phys. B

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When the contacts of medium-voltage DC air circuit breaker (DCCB) are separated, the energy distribution of arc is determined by the formation process of near electrode sheath. So, the voltage drop through the near electrode sheath is an important means to build-up the arc voltage, which determines the current-limiting performance of the DCCB directly. A numerical model describing the near electrode sheath formation process can provide insight into the physical mechanism of the arc formation and thus provide a method for arc energy regulation. In this work, a two-dimensional axisymmetric time-varying model of a medium-voltage DCCB arc when high-current interrupted was established based on a fluidchemical model involving 16 kinds of species and 47 collision reactions. The transient distributions of electron number density, positive and negative ion number density, net space charge density, axial electric field, axial potential between electrodes and near cathode sheath were obtained from the numerical model. The computational results show that the electron density in the arc column increases, then decreases, and then stabilizes during the near cathode sheath formation process, and the arc column diameter gradually becomes wider. The 11.14–12.33 V drops along the 17 µm space charge layer away from the cathode (65.5–72.5 kV/m) when the current is verying from 20–80 kA. The homogeneous external magnetic field has little effect on the distribution of particles in the near cathode sheath core, but the electron number density at the near cathode sheath periphery can increase with the magnetic field increasing and the homogeneous external magnetic field will lead to arc diffusion. The validity of the numerical model can be proved by comparison with the experiment.

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“…It may be noted that the cases mentioned above are accidental observations reported by researchers in the course of the experiments. While the technology of the arcjet has matured [21], a recent numerical study [22] on the effects of protrusion on DC arc anode attachment was carried out, but to the best of the authors' knowledge, there has been no study so far with an explicit focus on the effect of misaligned cathode tip on arcjet thruster performance. The asymmetry in the alignment of the cathode with the anode may lead to a change in thruster performance and may also give rise to a nonaxial side thrust, which is the focus of the present work.…”

Section: Introductionmentioning

confidence: 99%

A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

Nandyala

Kumar

Jayachandran

2023

Plasma Sci. Technol.

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In an arcjet thruster, the cathode and constrictor degrade with time, and the electrical arc discharge may become unsymmetrical. In this work, a three-dimensional numerical model of hydrogen plasma arcjet is developed and validated to study the effect of unsymmetrical electric arc discharge on thruster performance. The unsymmetrical arc discharge is realized by introducing a radial shift of the cathode so that the cathode tip offset is 80 μm (25 % of the constrictor radius). Simulations are conducted for both axially centered cathode (coaxial) and off-centered cathode (non-coaxial) configurations with identical propellant flow rates and input current. Simulations show asymmetrical arc discharge in non-coaxial cathode configuration, resulting in azimuthally asymmetric Joule heating, species concentrations, and velocity field. This asymmetry continues as the plasma expands in the divergent section of the nozzle. Temperature, species concentrations, and axial velocity exhibit asymmetric radial distribution at the nozzle exit. The computed Joule heating was found to reduce with cathode shift, and consequently, the thrust and specific impulse of the thruster was decreased by about 6.6 %. In the case of the non-coaxial cathode, geometric asymmetry also induces a small side thrust.

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Numerical simulation of the effects of protrusion on DC arc anode attachment

Cited by 11 publications

References 63 publications

Study of plasma-related parameters and self- generated TMF of contact under DB-DC VCB delayed breaking conditions

Study of plasma-related parameters and self- generated TMF of contact under DB-DC VCB delayed breaking conditions

Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

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