Wear principle and wear type of centrifugal fan impeller

Damage principle of centrifugal fan:

There are many factors causing the damage of centrifugal fan, most of which are the result of multiple mechanisms. Typical damage includes erosion wear and scratch dust particle damage. The solid particles enter the impeller and interact with the wall. In the inlet area of the centrifugal flow passage and the entire axial flow passage, the solid particles are basically affected by the entrainment of the air flow and their own inertia, hit the wall at a non-zero angle of attack, and then rebound into the flow passage. In this way, the wear of wall materials is typical erosion wear. However, in the outlet area of the centrifugal flow channel, the dust particles moved a long distance in the flow channel, most of which had multiple collisions with the wall. They basically roll or roll along the pressure surface, exerting certain pressure on the wall. In this way, the damage of the back material belongs to the damage of scratched dust particles, and the concentration of dust particles around the pressure surface increases the damage of dust particles.

The types of damage are:

1 Abrasive wear

The solid particles in the fan move relative to the surface of the part at a certain speed, which will cause abrasive wear. Uneven contact surface damage caused by filing effect under relative motion or grinding effect of dispersed solid particles between interfaces. It has a great impact on the extent of impeller damage.

2 Adsorption damage

If other conditions are the same, even if the machining accuracy and cleanliness of the machined surface are improved and better matched, the damage will not be reduced. On the contrary, due to the close interface, the molecular adsorption effect is obvious, which aggravates the interface damage, which is called adsorption damage.

3 Scour damage

The surface scratch caused by solid particles scouring the metal surface is called scouring damage.

4 Fatigue wear

Fatigue wear is caused by surface crack or desquamation caused by surface fatigue stress (or temperature or impact).

In short, from the perspective of damaged impellers, the conditions and locations of various types of impeller damage are different. However, the damage methods are mainly those mentioned above, all of which are local damage. The damaged parts are mainly on the working surface of the blade and near the back plate.