Research on precise and stable seed flow delivery control for plasma MHD power generation

Abstract

In this paper, a technique for precise and stable delivery control of alkali metal seed flow is proposed and experimentally verified. A high-pressure syringe driven by a stepping motor delivers liquid alkali metal seeds through a pneumatic atomizing spray gun. The seed jet is uniformly mixed, heated, vaporized and ionized by the high-temperature main flow in the plasma generator to produce a plasma with high conductivity. Based on the high-temperature arc wind tunnel test platform, an experimental study of the alkali metal cesium seed flow measure and plasma ionization characteristics was carried out. The results show that the fluctuation range of the measured seed flow was 5.93-10.39% at a small flow rate of 19 mL/min. For the back pressure of 6 atm, the fluctuation range of the measured seed flow is 6.04-11.55%, which proves that the back pressure of the plasma generator has insignificant effect on the seed flow. The plasma ionization characteristics test shows that the conductivity of the argon cesium equilibrium plasma is between 26.93-31.69 S/m, indicating that the ionization characteristics of the plasma are relatively stable, which can indirectly prove that the seed system has a precise and stable flow rate during the actual power generation. Key words: MHD power generation, alkali metal seed, seed fraction, precise and stable injection. Tables 1, Figs 9, Refs 11.