Effect of technological parameters on hydrodynamic performance of ultra-high-pressure water-jet nozzle

With the increasing requirement for environmental protection in the area of ship rust removal, ultra-high-pressure (UHP) water-jet technique attaches much attention. Because derusting nozzle is one of the key parts to determine the efficiency of a UHP rust removal system, a better understanding of its technological parameters is required. According to the operation characters associated with UHP water-jet derusting nozzle, the 3D simulations are performed to investigate the nozzle's hydrodynamic performance, taking the cavitation effect, multiphase flow and liquid compressibility models into account. Subsequently, according to the rule of the Latin hypercube sampling (LHS) method, 400 datasets are determined. Pearson correlation, Kendall correlation and Spearman correlation coefficients are selected to analyze the database of UHP water-jet nozzle. It is found that the standoff distance (SOD) and jet angle have the most dominant effect on the magnitude of wall shear stress. Finally, the influence of different SODs and jet angles on hydrodynamic performance of UHP water jet is analyzed by regarding the distribution trends of wall pressure and wall shear stress on target surface as critical contrastive indicators. The distribution rules of the peak wall pressure and wall shear stress on target surface which are attributed to the variation of SODs and jet angles are summarized, and the optimum combination of these two key technological parameters is proposed. This related research provides a reference for the determination of technological parameters.