Design optimization and flow field analysis of the nozzle structure of a foreign fiber sorter

With the purpose of solving the problems of uneven velocity and energy loss of the foreign fiber sorters, this paper has analyzed the nozzle distribution and structure in the foreign fiber sorting system, and presented the design of a nozzle with the circular distribution contraction–expansion structure. The turbulent kinetic energy was optimized through a circular distribution of the nozzle to improve nozzle velocity uniformity, according to the effect of air flow on wall surface distance. Meanwhile, the nozzle was optimized with the contraction–expansion structure based on the relationship between the Mach number and the nozzle’s cross-sectional area. The stepped cross-section of the nozzle was replaced by a transition curve cross-section to restrain the sudden change of the air flow velocity in the nozzle. The optimized nozzle structure was discussed in terms of the velocity, the pressure, and the energy loss. It was found that the velocity increases by 9.2%, the required pressure decreases, and the energy loss decreases. So the effectiveness and practicability of the proposed method were illustrated.