Pulsed combustion device having a discharge port with a return flow valve and a combustion chamber shaped as a helmholz resonator

摘要

A pulsed combustion device (1) for used in an underground borehole comprises a substantially tubular combustion chamber (10) and separate fuel and oxidant supply conduits (2, 6) for supplying fuel and oxidant to the combustion chamber. One of said conduits has a fluid discharge port equipped with return flow limitation means (13) located at the upstream end of the chamber and the combustion chamber is shaped as a Helmholz resonator having a tailpipe section (15) of which the internal diameter is significantly smaller than the other parts of the combustion chamber.