Effect of Coating Thickness on a Solid-Liquid Two-Phase Flow Centrifugal Pump under Water Medium

Spraying a coating on the surface of wet parts of a solid-liquid two-phase flow centrifugal pump could effectively increase its service life. To research the effect of coating thickness on the performance of the pump, a solid-liquid two-phase flow pump with a speed of n s = 81.5 was chosen, and polyurethane coatings with different thicknesses were sprayed on the surface of the blades of the impeller. The influence of coating thickness on the performance of the pump was tested under the condition of a water medium. Combined with numerical simulation, the internal flow, pressure fluctuations and radial force of the model pump were further analysed in detail. Keeping the blade outlet angle unchanged, the head and efficiency of the pump decrease with the increase of the coating thickness, and the amplitude of the decrease increases with the increase of the coating thickness. The peak value of pressure fluctuations increases with the increase of coating thickness. The pressure value on the impeller inlet increases first and then decreases with the increase of coating thickness. Radial force of impeller increases with the increase of coating thickness, and the radial force distributes in the triangle, which is the same as the number of blades.