Mechanism of jet-angle effects on cutting depth in abrasive air jet cutting of metallic targets

摘要: Abstract：During nuclear facility decommissioning, cutting stainless steel components requires efficient material removal while minimizing thermal effects and secondary waste. Abrasive air jet cutting, characterized by water-free and low-heat operation, shows potential for cold dismantling applications. However, in moving cutting with a rectangular nozzle, a 90° jet angle provides a large single-particle normal velocity component but does not necessarily produce the best cutting performance. The formation mechanism of the optimal jet angle therefore remains unclear. To address this issue, cutting experiments on 304 stainless steel were conducted under different jet angles using a rectangular-nozzle abrasive air jet, and a CFD-DEM coupled numerical model was established to analyze the effects of particle distribution, normal velocity variation, and target-surface contact force on cutting depth. The results show that the cutting depth first increases and then decreases with increasing jet angle. The maximum cutting depth of 9.8 mm occurs at 45°, whereas the cutting depth at 90° is only 2.8 mm, indicating that the maximum single-particle normal velocity component does not correspond to the optimal cutting effect. The numerical simulation results agree well with the experimental trend. Further analysis shows that the jet angle adjusts the average effective normal impact effect of the abrasive group by varying the number of effective particles, the change in normal velocity before and after particle collision, and the effective effective area of the target surface, thereby affecting the cutting depth. At smaller jet angles, the particle normal velocity component is low and the impact area is large, resulting in insufficient normal impact per unit area. As the jet angle increases to an appropriate range, normal momentum transfer is enhanced and cutting depth increases. When the jet angle further approaches 90°, reflected particles increasingly overlap and interfere with subsequent incident particles, reducing the number of effective particles and decreasing cutting depth. This mechanism suggests that the optimal jet angle depends on nozzle structure, target material properties, and the effective action state of the particle swarm. These findings provide a reference for optimizing jet angle and cutting parameters in abrasive air jet cold cutting for nuclear facility decommissioning.