No-moving-part commutation of gas flows in generating plasma by cumulative detonations (survey)

This paper surveys controlling, without use of mechanical valves, of flows of three gases: a combustible mixture (fuel and oxidant), combustion products, and a neutral scavenging gas. The gases are delivered periodically in an alternating way into a pair of pulsed MHD electricity generators. Essential problem of this type of electricity generation is insufficient ionisation level of combustion products in the usual deflagration type burning. Solution was found in achieving momentarily extremely high temperatures by cumulative detonations. In the 1st phase the cavities leading into the 1st MHD generator are filled with the combustible mixture, which is then ignited, generating a high-temperature high-speed detonation wave moving into the generator. In the subsequent 2nd phase the combustion product are scavenged in the cavities by the neutral gas. In the other generator the phases are in reversed order. Because of the extreme temperature, the flows are switched not by mechanical valves but by no-moving-part devices, in various configuration that are systematically surveyed. •Commutator is important part of direct MHD electricity generation.•Reciprocating scavenging and filling of cavities for cumulative implosions.•Absence of moving parts leads to commutator robustness.