Numerical Simulation of the Electrode Degradation Effect on Faraday MHD Accelerator

In this work, a three-dimensional numerical simulation is carried out on an ideal Faraday MHD accelerator for the thrust boosting effect in terms of the single electrode degradation. The study is performed by using a low magnetic Reynolds number magnetohydrodynamic model and Gaussian distribution conductivity model to simplify the electron beam ionization. The channel uses a total of 20 pairs of electrodes, while the failed electrodes are the 2nd, 8th, 14th, and 20th pairs, respectively. The results show that the failure of a single electrode will change the distribution and magnitude of the current, causing a change in the Lorentz force, and then produce an effect on the velocity and thrust. The influence is closely related to the magnitude of the conductivity at the electrode. At the 2nd and 20th electrode pairs, the conductivity is less than 30 S/m and there is almost no effect on the channel when the electrode fails. The change rate of outlet velocity and thrust are both less than 0.5%. At the 8th and 14th electrode pairs, the conductivity is close to 100 S/m and 95 S/m respectively. When the 8th electrode pairs break down, the velocity of the central axis decreases by 15m/s, the thrust decreases by 1.4%, and the efficiency decreases by 0.5%. When the 14th electrode pairs lose efficacy, the velocity of the central axis decreases by 12 m/s, the thrust decreases by 1.1%, and the efficiency decreases by 0.3%.