Simulation for throttling effect of small aperture multistage orifice units

Throttling effect of small aperture multistage orifice units was studied through simulation method. It was found that strict initial flow field was needed in this kind of simulation, and the simulation would be dummy-balanced with irrational initial flow field. This problem was solved by iterative finding proper initial flow field. The multistage orifice units with 0.1 mm aperture and 0.025 aperture ratio were simulated. The simulation result shows that the number of the orifices is the major factor which influences the flow coefficients of the multistage orifice units. Fitted formulae for the flow coefficients were given depending on the simulation results. The fitted formulae can be applied to actual engineering design calculation.