Investigating the advantages of Laval blasting nozzles in combination with injector-type sandblasters using efficient numerical methods

Injector-type sandblasters are commonly sold with cylindrical of convergent-divergent Laval nozzles. While Laval nozzles are advertised to be more efficient, very little research on this topic has been published yet. Therefore, the advantages of Laval blasting nozzles in combination with injector-type abrasive blasting units were evaluated within this paper. Numerical simulations on basis of different solvers have been utilized to calculate the compressible multiphase-flow and also to identify the ideal numerical model in terms of stability and computational effort. By comparing flow and particle velocity distributions of cylindrical nozzles against the results of Laval-type nozzles, it has been found that using the latter type offers an increased productivity and a more uniform particle velocity distribution at the same air and particle flow rates. Further, it was concluded that the air flow rate and therefore the pressure and compressor energy demand can be reduced significantly without losing productivity in abrasive blasting.