In order to discuss the surface pressure pulsation characteristics of the magnetic-fluid sealing membrane of centrifugal pump, this paper studies the surface pressure pulsation characteristics of the shaft end sealing membrane under different flow operating conditions of centrifugal pump based on the combination of numerical calculation and experimental verification. The results show that the pressure value on the surface of the magnetic-fluid sealing film decreases with the increase of the flow rate of the centrifugal pump, and the pressure on the surface of the magnetic-fluid sealing film has periodic pulsation, and the period is the time required for a single blade to sweep the volute separating tongue. In one rotation cycle of the runner, the number of reciprocating movements of the magnetic-hydraulic sealing film is the same as the number of blades of the runner. The main reason for the pressure pulsation is that the impeller periodically sweeps the fixed surface of the centrifugal pump.

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In a liquid environment, the turbulence intensity of the interfacial layer between the magnetic and sealing medium fluids in magnetic liquid seals directly affects the layer stability. Reducing the maximum turbulence intensity of the fluid interface layer effectively improves the stability of the magnetic fluid rotary seal. In this study, we simulated magnetic fluid sealing devices with different structures in liquid environments using the FLUENT software. The simulation results were verified through experimental analyses of the turbulence intensity at the sealing interface. The maximum turbulence intensity of the liquid interface layer increased with increasing shaft speed. At the same speed, the turbulence intensity was maximized at the shaft interface before gradually decreasing in a multistage linear pattern along the radial direction. A magnetic liquid seal with an optimized structure (OS) in the liquid environment was designed based on these results. The maximum turbulence intensity of the liquid interface layer in the OS was independent of the rotation speed and was more than 20% lower than that that in the traditional structure. These results provide a reference for designing magnetic liquid sealing devices.

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