赤外線カメラを用いたコールドスプレーノズル内部流動の推定

抄録

Cold Spray (CS) is a coating technology in the thermal spray family. In this process, the particles with mechanically excellent properties are accelerated to high velocity by supersonic flow of the inert gas through a convergent-divergent nozzle (Laval nozzle) and impact on the substrate surface. The deposition efficiency of the particles is affected by particle velocity, which depends on gas velocity in the CS nozzle. This study shows a new method to estimate the gas flows in the CS nozzle. The method measures the outer surface temperature of the CS nozzle using an infrared camera, and then estimates the gas flows in the CS nozzle. Mach number estimated using the infrared camera was validated by comparing them with local Mach number measured by using the wall pressures. The method can estimate the gas flows with high precision over the entire CS nozzle. However, it is required to reduce the influence of the entrainment effect near the CS nozzle exit.