ラバルノズルから噴出される超音速衝突噴流の数値解析

抄録

Laval nozzle is commonly used in the cold spray processing, which is a material deposition process using supersonic gas flow. Small powder particles of material are injected into the gas flow and accelerated to velocities enough to form film on a target surface. The velocity of gas flow inside and downstream of nozzle is one of the important factors to determine the collision speed of particles onto the target. In this study, the jet issuing from two dimensional laval nozzle and impinging on a flat plate is numerically simulated. By mounting a cover to the nozzle exit, the jet boundary attaches to the cover wall, the base pressure decreases, and the jet is further accelerated downstream of nozzle because of higher pressure ratio. Flow fields with different cover widths and lengths are compared with each other and the effects of such parameters on the collision speeds of particles are discussed.