The blades of the centrifugal fan are an important part of the equipment, and there are many types. We need to choose according to our own needs, so how are the specific centrifugal fan blades divided?
2)Classification of centrifugal fan blade types
1. Rearward blade
The bending direction of the backward blade is consistent with the natural motion trajectory of the gas, opposite to the rotation direction of the impeller, and the outlet installation angle is less than 90°, which has the advantages of low noise, low energy loss and high efficiency. type of airfoil.
2. Forward blade
The bending direction of the forward blade is opposite to the motion trajectory of the gas, and is the same as the rotation direction of the impeller. The installation angle of the outlet is more than 90°. The gas is forcibly changed direction, and the noise and energy loss are relatively large, the efficiency is low, and the total wind pressure is high. .
3. Radial blades
The outlet direction of the radial blade is radial, and the installation angle of the outlet is 90°. It has the advantages of simple structure and not easy to accumulate dust. It is mostly used in powder dischargers or induced draft fans.
In general, when other conditions are the same, the total pressure head of the forward blade is larger than the other two, but the dynamic pressure head accounts for a larger share of the total pressure head, the energy loss of the flow channel is large, and the efficiency is low. However, the total pressure head generated by the backward-facing blade is small, but the static pressure head accounts for a large proportion of the total pressure head, the energy loss of the flow channel is small, and the efficiency is high. Therefore, the backward-facing blade is commonly used in general boiler fans.
2) centrifugal fan blade shape classification
1. Airfoil
The blade of the airfoil has high efficiency, high stiffness, high strength and good aerodynamic characteristics, but the manufacturing process is more complicated, and the blade is relatively easy to wear. If the blade is worn through, impurities will directly enter the interior of the blade, resulting in the loss of the impeller. balance and vibrate.
2. Flat type
The flat straight blade is relatively simple to manufacture, but has poor flow characteristics. Compared with the flat curved blade and the airfoil blade, except for the higher efficiency point and the lower efficiency nearby, the efficiency of other operating points is basically similar.
3. Arc shape
The arc-shaped blade is more suitable for the forward impeller. In the backward impeller, airfoil blades are commonly used in large fans, and the induced fans of coal-fired boilers with low dust removal efficiency can use arc-shaped blades and flat blades.
The above is the answer to the question of how to classify centrifugal fan blades. After the above introduction, it can be seen that centrifugal fans can be divided into backward blades, forward blades, radial blades, etc. according to the blade type, and can be divided into airfoil type, Flat type, arc type, etc., each with different characteristics and can be selected according to different equipment.
