A pulsed MHD generator for electric launcher

Abstract

An invention scheme of pulsed MHD generator (PMHDG) in milliseconds order of magnitude that can be used directly in electric launchers is presented for the first time. It is either different from ordinary small power DC MHD generators for power plants, or different from explosive MHD generators where its pulsed current width is in the microseconds order of magnitude. Operating principle of the PMHDG is as follows: fuels or oxidizing agents within two storage vessels are injected into a combustion chamber to combust by a pump and a valve, after waiting for the pressure (or density) of generated conductive electric MHD ascends some threshold value, a self-controlled valve in combustion chamber throat is opened automatically. As a result, conductive electric MHD passes into a generating channel in pulse to generate electric current. Obviously, control the amount of the working substance entering into the combustion chamber with the injector valve, and adapt the spring pressure of the self-controlled valve, then we can control the pulse width and obtain different values of high power to be used directly by electric launcher. Besides, this paper gave a theory-mathematical model in which some characteristics of the generator were expressed. This helps us to understand the relationship between various physical quantities about the generator, and provides a basis to research their mutual influences. In addition, in physical design of the circuit, we adopted a proper high energy density capacitor as auxiliary energy storage. On one hand, the generator can realize the self-excited generation by using the capacitor; on the other hand, the high energy capacitor is charged directly by the generator and energy store within the capacitor is realized, so as to form a generator-capacitor combined high power pulsed power supply, which can be used by high energy electric launchers.