Mixing Characteristics of a Reciprocating Stirring Device Based on VOF–DPM Coupling

Diamond particles tend to disperse non-uniformly during the electroplating sand-setting process of diamond wire manufacture. To address this problem, the gas–liquid–solid three-phase flow characteristics in a baffled semi-circular reciprocating mixing tank were numerically analyzed by means of CFD(computational fluid dynamics). A VOF–DPM (Volume of Fluid–Discrete Phase Model) coupled gas–liquid–solid model was established to investigate the flow-field evolution within a stirring cycle, the velocity distribution characteristics, and the influence of the reciprocating frequency on mixing performance; the particle mixing uniformity of the reciprocating stirring device was further verified by sampling experiments. The results show that three typical dynamic vortex regions are formed in the tank, located above and below the stirring plate and outside the baffle, and the flow structure evolves periodically with the motion of the stirring plate. The reciprocating motion of the flat plate exerts a pronounced velocity-amplification effect on the fluid: the maximum axial velocity in the tank can reach 1.95 times the maximum velocity of the stirring plate. Increasing the reciprocating frequency raises the overall flow velocity and improves the uniformity of the velocity distribution, but does not change the basic flow pattern. Under the process condition of 0.5 Hz, which was evaluated experimentally by multi-point sampling (the CFD simulations were performed at 0.25, 0.62, and 1.00 Hz), the relative standard deviation of the diamond particle mass fraction is 4.62%, satisfying the requirements of the diamond wire electroplating sand-setting process. The results provide a theoretical basis for the structural optimization and process parameter regulation of reciprocating stirring devices for diamond wire sand-setting.