Wear Mechanism of Flow Parts in Mud Pumps

At present, the solid-liquid two-phase flow mud pump is widely used in water conservancy dredging projects. However, in the actual application process, due to the existence of a large amount of sediment in the water flow, the impeller of the mud pump has serious wear, which seriously affects the normal operation of the mud pump.

Therefore, through the analysis of the wear mechanism and law of the impeller of the mud pump, it is of great practical significance to propose methods and measures to reduce the wear of the impeller of the mud pump.

Ⅰ. Wear of the impeller of the mud pump

The impeller of the mud pump is an easily worn part, and the outlet of the impeller is one of the most severely worn parts.

From the inlet to the outlet, the wear grows from scratch, develops gradually from large to small, and develops in the depth direction, while the back of the mud pump blade wears less, mainly with shallow depressions, and the front and rear cover plates of the impeller wear more evenly. Wear is light.

Ⅱ. Wear mechanism of mud pump

Due to the complexity of the solid-liquid two-phase flow in the pump, the wear in the mud pump is also quite complicated.

At the inlet of the impeller, the flow direction of the mud is changed from axial to radial, so only larger particles will hit the head area of the blade, so the wear of the blade is less at the inlet.

At the same time, in the process of mud flowing around the blades, due to the uneven work done by the blades, a pressure gradient is formed, and the boundary layer outlet near the non-working surface of the mud pump blade is prone to separation, resulting in de-flow and backflow phenomena, resulting in mud stratification.

The dense phase of the mud is close to the working face of the blade, and the dilute phase is close to the back of the blade, which leads to increased wear on the working face of the blade and the outlet of the impeller, while the back of the blade wears less.

When the mud enters the cover plate from the impeller, due to the action of inertia, the particles gather in the near-wall area, resulting in the wear of the cover plate.

Ⅲ. Factors affecting the wear of the impeller of the mud pump

There are many factors affecting the wear of the impeller of the mud pump, mainly in the following aspects.

One is the flow conditions of the mud pump, such as the flow velocity of the mud, the concentration of solid particles, the properties of solid particles and the interaction between liquid-solid two-phase fluids.

The second is the structural design of the mud pump: the diameter and width of the impeller; the number of blades, the angle of inlet and outlet, etc.

The third is the material selection of the mud pump flow element.

Ⅳ. The impact of wear on the mud pump

1. The influence of wear on the performance of the pump: the wear makes the outer diameter of the impeller shorter, and the hydraulic loss in the impeller rises sharply, resulting in a drop in the pump head;

Due to the wear, the matching clearance of the pump's overcurrent parts increases, and the flow rate and volumetric efficiency decrease; when the wear is severe, cavitation will be induced, and the combined effect of wear and cavitation will make the pump wear more serious.

2. Wear deteriorates the operating environment of the pump: wear and tear can easily lead to the failure of the shaft seal of the mud pump, resulting in leakage, resulting in increased vibration.

3. The increase in the operating cost of the mud pump caused by the wear: the wear leads to a faster replacement frequency of the overflow components of the mud pump accessories, and the maintenance and repair work is increased, resulting in a great increase in the operating cost.