Experimental investigation of elements of the structure of the inlet portion of the paste-cooled channel of a reusable pulsed MHD generator

The results are given of experimental investigation of the heat resistance of elements of the structure of the inlet portion of the paste-cooled chann el of a reusable pulsed MHD generator. The gas generator is provided by a t est-bed rocket engine utilizing Tonka-250 + HNO3 propellant. The basic test s are performed using the above-identified propellant with the addition of aluminum powder, this making the combustion products of such a gas generato r similar to the combustion products of standard solid propellant as regard s their composition and effect on structural materials. The square-throat n ozzle of the engine has paste-cooled copper walls. The wall design is analo gous to that of the inlet portion of the MHD channel wall. Two pastelike co oling agents are tested, namely, a carbamide-based melting agent and an amm onium oxalate-based sublimating agent. Firing tests prove the operating eff iciency of the copper walls when cooled by pastelike cooling agents of the two types under conditions of repeated heat loading. The duration of a sing le test is 4 to 15 s, the heat flux is up to 9.5 MW/m(2), and the flow rate of the sublimating cooling agent is up to 4.8 kg/m(2) s. It is confirmed t hat a liquid-propellant gas generator is a convenient tool in development t esting of MHD channel structures for heat resistance under conditions of re peated operation.