Numerical simulation of supersonic plasma jet formation using straight and angled nozzles in air-plasma powder spraying
D.V. Bedenko, O.B. Kovalev, P.A. Tyryshkin, A.S. Tambovtsev, V.I. Kuz’min, I.P. Gulyaev
S.A. Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: plasma spraying, modeling, gas dynamic, supersonic nozzle, high-enthalpy jet, compact plasma torches
Abstract
This paper presents a comparative numerical simulation of supersonic plasma jets generated by a DC plasma torch using straight and angled nozzle configurations. A numerical analysis of the nozzle design developed by the authors is performed in the context of air-plasma powder spraying onto internal surfaces of small-sized components. The gas dynamics of mixing between the high-temperature jet of the plasma-forming gas and the flows of cold carrier and focusing gases is investigated within and downstream of the annular powder injection unit. Verification is carried out and comparative data on shock diamond positions are obtained for the case of a slightly under-expanded jet. The effect of wall cooling on jet enthalpy is calculated, demonstrating its significant influence in the case of the angled nozzle design. For this nozzle type, characteristic distances are determined at which the velocity and temperature profiles of the jet core become uniform and axisymmetric.
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