Optimization of a rotationally staggered multistage orifice plate for low noise throttling

Multistage orifice plates are widely used for pressure reduction and flow regulation, but conventional coaxial designs can lead to concentrated jets, local low-pressure regions, cavitation risk, and flow-induced noise. To improve throttling performance while reducing noise, a rotationally staggered multistage orifice plate is proposed, in which the holes in adjacent plates are circumferentially offset by a fixed angle. A numerical model based on the SST k – ω turbulence model is established and validated against experimental data, achieving a pressure drop error of less than 10%. The staggered arrangement is compared with conventional coaxial structures, demonstrating enhanced pressure-reduction capability and reduced low-pressure regions. An optimization framework combining Latin hypercube sampling, Spearman correlation analysis, surrogate modeling, and non-dominated sorting genetic algorithm II (NSGA-II) is developed. Compared with the original staggered structure, the optimized design maintains the required pressure drop, reduces the low-pressure magnitude by 12.0%, and decreases the maximum velocity by 3.37%. These results demonstrate the potential of the proposed design as a passive strategy for reducing noise in multistage throttling components.