Influence of inlet swirl angle on alkali aetal seed mixing effect of inert gas disk MHD generator

P. Zhu^1,2 - A. Peng^1,2

¹ University of Chinese Academy of Sciences, Beijing 100049, China
² Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China

Abstract
For the high temperature plasma disk MHD generator test device, the Institute of Electrical Engineering, Chinese Academy of Sciences proposed an accurate and stable injection system of alkali metal seeds based on a pneumatic atomization nozzle, which can realize the quantitative delivery of seed flow to the upstream mixing chamber of the generator on demand, vaporize the seeds through the heat transfer between the high enthalpy inert gas and alkali metal seeds, and evenly mix the seed jet with the main inert gas flow. In this paper, the mixing process of alkali metal seeds injected by the pneumatic atomizing nozzle and high- temperature argon in the upstream and inside the generator is numerically simulated. Under typical working conditions, the effects of different inlet swirl angles on the mixing effect of alkali metal seeds were simulated and analyzed when four spray guns were evenly distributed. The spatial distribution and variation of the seed fraction in the disc channel were emphatically analyzed. The uniformity of seeds in the effective section of the channel was evaluated by calculating the non-uniformity coefficient of gaseous cesium. The plasma ionization characteristics of the anode inlet of the power generation channel were also evaluated. The results show that the increase of the swirl angle at the inlet has a negative impact on the seed fraction level of the power generation channel. The plasma conductivity distribution at the anode inlet is related to the spatial distribution of seeds. Under the condition of inlet swirl, the total electron number density at the anode inlet will decrease by about 2-3 orders of magnitude. Tables 3,Figs 9, Refs 7.