Calculation of Voltage-ampere Characteristic about Thermionic Energy Converter Based on Kinetic Method

The calculation of voltage-ampere characteristic (VAC) of thermionic energy convertor is the primary issue in the calculation and analysis of electrical character. The model of plasma transport in the electrode interval was built based on kinetic method to calculate the VAC of thermionic energy converter. And the model of plasma transport was simplified according to the collision characteristic of weak ionization plasma. For the partial differential boundary value problem to be solved, the adaptive computer program based on try-shooting method was adopted to solve the transport equations and boundary conditions and the calculation program was built with MATLAB language. The model was verified in the broad scope of the emitter ion-richness ratio β and the transport parameters P_Csd, covering their critical values. It is found that the results of VAC and distribution of plasma parameters calculated in this thesis accord with the experiment results well. The average relative error between the VAC curve and the experimental measurement is 14.2%. The calculated values of the electron temperature and plasma concentration at the electrode gap are in good agreement with the measured values. The overall offset of the electron potential energy distribution is due to the experimental measurement deviation of the potential energy jump of the sheath layer electrons. The calculated trend of the change is in good agreement with the experimental value. Based on the parameter normalization, combined with the comparative analysis of the volt-ampere characteristic curve and the distribution of plasma parameters, it is verified that the plasma transport mechanism model of the computerized physical principle program for the VAC is reasonable and the results are accurate. The input parameters have a wide adaptability, and the program can be used for the electrical characteristic analysis of thermal ion energy conversion.