Cross-flow fan, also called cross-flow fan, was first p […]
Cross-flow fan, also called cross-flow fan, was first proposed by French engineer Mortier in 1892. The impeller is multi-blade, long cylindrical, and has forward multi-wing blades. When the impeller rotates, the airflow enters the blade cascade from the open part of the impeller, passes through the interior of the impeller, and is discharged into the volute from the other side of the cascade to form a working airflow. The air flow in the impeller is very complicated, the air velocity field is unstable, and there is a vortex in the impeller, the center is located near the volute tongue. The existence of the vortex causes a circulating flow at the output end of the impeller. Outside the vortex, the airflow streamline in the impeller is arc-shaped. Therefore, the flow velocity of each point on the outer circumference of the impeller is not consistent. The closer to the vortex center, the higher the speed, and the closer to the volute, the lower the speed. The air velocity and pressure at the air outlet of the fan are not uniform, so the flow coefficient and pressure coefficient of the fan are average values. The position of the vortex has a greater impact on the performance of the cross-flow fan. The center of the vortex is close to the inner circumference of the impeller and close to the volute tongue, and the performance of the fan is better. The degree of stability increases.
Its working principle: the cross-flow fan is mainly composed of three parts: impeller, air duct and motor. The impeller material is generally aluminum alloy or engineering plastics. The aluminum alloy impeller has high strength, light weight, high temperature resistance, and can maintain stable operation for a long time without deformation; the plastic impeller is injection molded by a mold and then welded by ultrasonic waves. It is generally used in low-speed occasions with a large diameter.
The air duct is generally stamped and formed by sheet metal, and it can also be cast in plastic or aluminum alloy. The casing adopts a streamlined design, which can effectively reduce the loss of airflow and greatly improve the working efficiency of the fan.
The electric motor is the power part of the cross-flow fan, and it can be powered by AC or DC. AC power supply mainly includes shaded pole motors and capacitor starter motorsEC backward centrifugal fans Manufacturers, while DC power supply is DC brushless motors. The drive motor is generally flexibly installed with the impeller and fixed on the air duct.
Advantages and disadvantages of cross-flow fans:
1) The axial length is not limited, and the length of the impeller can be selected arbitrarily according to different use needs;
2) The airflow flows through the impeller and is affected by the two forces of the blades, so the airflow can reach a long distance;
3) No turbulence, uniform air flow;
4) Because the airflow is forced to turn in the impeller, the head loss is large and the efficiency is low.