ABOUT A QUESTION OF DETERMINING KINEMATIC AND THERMODYNAMIC PARAMETERS IN PLASMA JET

When using special attachments in agricultural machinery, one often has to deal with the failure of the hydraulic systems for driving the working bodies due to wear of the contacting friction pairs. The process of applying gas-thermal composite coatings by plasma deposition to restore such defects is considered. The dynamics of the behavior of a single particle in a flow without taking into account the interaction of neighboring particles was studied to determine the parameters of the plasma jet, which provide precipitation of a given quality. The criterion of controlled melting of composite material particles was used. This ensures, on the one hand, obtaining the required adhesion of the coating to the treated surface, and on the other hand, it creates compressive residual stresses in the formed layer. The problem is solved under the assumption that the space is isotropic. The effects of elastic-plastic deformation are not taken into account. An algorithm is presented for the numerical solution of constitutive relations that describe the nature of the motion of a plasma jet depending on the external factors that determine it. The dependences of the particle velocity on the distance traveled by them and their temperature depending on the size of the fraction of the solid part of the filler are presented for the case of using aluminum oxide particles with a diameter of 45 μm as a filler. The regularities obtained make it possible to predict in advance the properties of deposited coatings, achieving certain features determined by the operating conditions of the restored unit.