Вплив режимів роботи нагрівача установки газодинамічного напилювання на температуру нагрівання стисненого повітря

One of the key parameters in the cold gas dynamic spraying process, which affects the formation of the physical and mechanical properties of coatings and the powder utilization rate, is the velocity and temperature of powder particles upon impact with the surface. The acceleration and heating of powder particles occur in a supersonic converging–diverging nozzle for spraying, into which a hot pressurized flow from an ohmic electric heater is supplied. The gas temperature determines the flow velocity in the supersonic nozzle and, consequently, the velocity of the powder particles carried by this flow. The subject of this study is the regularities and characteristics of compressed air heating in the heater of a cold spray system. The aim of the work is to establish the regularities of compressed air flow heating in the developed heater depending on the variation of air mass flow rate through the nozzle and the power of the heating elements. The task is to perform numerical modeling of the heating process of the compressed air flow as it passes through the heater of the spraying system, considering changes in air flow rate and heater power. Research methods. Numerical modeling was carried out using the SolidWorks Flow Simulation software package, which is based on the finite element method. Results. Numerical modeling has shown that the calculated heater power (18,5 kW) is sufficient to heat an air flow at 2.5 MPa pressure to an outlet temperature above 800 K, provided the maximum air flow rate is 0.001 m³/s. Data were obtained on the air flow temperature as a function of changes in flow rate. It was found that reducing the flow rate to 0.0008 m³/s and 0.0006 m³/s (which corresponds to 80% and 60% of the maximum flow rate, respectively) reduces the required heater power to 15 kW and 12 kW, respectively, to maintain the specified outlet temperature. Conclusions. A relationship has been established between the air flow rate through the nozzle and the required heater power to achieve the specified flow temperature at its outlet. The obtained results can be used to set optimal parameters for cold gas dynamic spraying to ensure high coating quality and process efficiency.