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Hao Li,Peng Lu,Hulin Huang,Yining Zhang,Chenyuan Liu 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.5
To adequately utilize the high enthalpy of the weakly ionized gas and improve the performance of the magnetohydrodynamic generator (MHDG) in a hypersonic channel, cesium salts are homogeneously injected into the gas at the entrance of the MHD channel for elevating the gas electrical conductivity. The finite rate chemical dynamics and multi-species electrical conductivity model for seven-species (N2, O2, N, O, NO, NO+, e−) were adopted to simulate the electrical conductivity of the weakly ionized gas under different magnetic fields. The results demonstrate that the electrical conductivity of the weakly ionized gas with cesium salts is significantly higher than that without cesium salts due to two positive contributions of cesium salts, one is that a portion cesium atom ionize much more electrons, and the second is that cesium salts reduce the activation energy of N + O <-> NO + e− by 3.5 times, which accelerates the production rate of electrons. The electrical conductivity of the gas with cesium salts is decreased monotonically along the flow direction, which is contrary to the trend of that without cesium salts. The variation of the collision frequency plays a crucial role in the electrical conductivity of the gas without cesium salts, nevertheless, this effect is marginal on the gas with cesium salts. The magnetic fields have negative impacts on the electrical conductivity of the gas with/without cesium salts. Additionally, the MHDG power generation efficiency is augmented with B for the gas with cesium salts, whereas the trend is reversed for that without cesium salts.