Optimization of High-pressure Nozzle Structural Parameters for Alumina Digestion Pipeline Cleaning via Orthogonal Experiment

The cleaning efficiency and effectiveness of a high-pressure water jet cleaning system depend largely on the nozzle design and structure parameters. First, the flow characteristics of nozzle jets with different structural types and parameters are investigated using computational fluid dynamics (CFD). Subsequently, L25(56) orthogonal tests are employed to optimize the multi-objective and multi-parameter performance. Statistical analysis reveals the order of significance of each structural parameter on jet flow performance, and the optimal parameter combination that yields the best overall jet effect is identified globally. The results show that the nozzle expansion angle and outlet diameter have the greatest influence on the jet velocity: the expansion angle is negatively correlated with exit velocity, while the outlet diameter is positively correlated. The optimized nozzle structure yields a 12.90% increase in exit jet velocity, a 3.80% reduction in jet dispersion, and a 36.21% enhancement in total pressure at the target surface. Finally, the cleaning effect is improved by 28.52%.