In many fields such as electronics, home appliances, medical and agricultural equipment, crossflow fans have gradually become the first choice for efficient and silent heat dissipation solutions due to their unique air supply method and structural design. This article will briefly analyze the structural characteristics, application advantages and differences between crossflow fans and axial flow fans from three perspectives: principle, comparison and performance testing.

1. Structure and airflow characteristics of crossflow fans

Crossflow fans (also known as crossflow fans or radial intake fans) are composed of multi-blade cylindrical impellers, volutes and volute tongues. The impeller is partially open and partially surrounded by the volute. The air inlet is an open structure, and there are no air inlets on both sides like centrifugal fans. When the fan is running, the airflow enters the blade grid from the open side, passes through the impeller and is discharged from the volute from the other side, forming a wide working airflow. The internal airflow is complex and in an unstable state. It has been observed that a vortex center will be formed in the impeller, usually near the volute tongue. The vortex affects the efficiency and stability of the fan: When the vortex is close to the volute tongue, the fan has better performance and higher efficiency; If the vortex is far away from the volute tongue, the circulation area increases, the fan efficiency decreases, and the flow stability weakens. The shell structure, the position of the volute tongue and the pressure difference between the inlet and outlet will affect the vortex position. At present, optimization still needs to rely on experimental verification. Application characteristics: A large flow rate can be achieved even at a small diameter; The wind pressure distribution is relatively uniform; It is suitable for long strip structures or equipment that requires uniform cooling (such as display screens, purifiers, etc.); Flexible installation, compact structure, suitable for flat spaces.

2. Performance comparison between cross flow fans and axial flow fans

Axial flow fans deliver air by flowing along the axial direction, and are often used in ventilation occasions that require concentrated wind pressure and large flow. It is mainly composed of a wind collector, an impeller, a guide vane and a diffuser. The impeller is a rotating component, and the other components are fixed. The axial flow fan is flexible in design, and the performance curve is greatly affected by the blade installation angle. Although it has certain advantages in air volume and energy conversion efficiency, it is in contrast with the cross-flow fan in the following aspects: Comparison items Cross-flow fan Axial flow fan Airflow direction Horizontally through the impeller Axially through the impeller Air discharge characteristics Uniform air discharge, suitable for long strips Concentrated air discharge, suitable for local forced cooling Installation structure Flat and compact, suitable for scenes with limited space Requires a larger installation depth, and the structure is relatively thick Noise performance Low-speed operation, low noise Slightly loud noise at high speed Common applications Display equipment, power modules, air purifiers Air conditioners, heat dissipation ducts, large electrical appliances heat dissipation.

3. Cooling fan performance experiment and actual test methods

Cooling fan design not only relies on theoretical calculations, but also needs to verify its performance through experiments. As a widely used device, the aerodynamic performance of cross-flow fans is often tested in the following ways.

Experimental device type Intake experimental device: suitable for suction duct occasions, simple structure, frequent use; Exhaust experimental device: used for air outlet duct fans; Intake and exhaust combined device: suitable for equipment with ducts at both inlet and outlet, more comprehensive testing.

Performance parameter measurement method The fan performance mainly focuses on the following parameters:

Flow rate (Q): can be measured by the collector (arc or cone), and the loss coefficient φ (generally 0.98~0.99) is taken into account;

Wind pressure: composed of static pressure and dynamic pressure, affecting the air supply intensity;

Power (N): The fan shaft power is obtained using the torque dynamometer or electric dynamometer;

Efficiency: obtained based on the input power and output air volume air pressure ratio.

These parameters jointly construct the fan performance curve, which is used to optimize product design and actual selection.

4. Summary

Common use advantages of cross flow fans Suitable for long strip air outlet requirements: such as power modules, screen cooling, purification outlets; Flexible installation and compact structure: save space, especially suitable for embedded devices; Good silent operation effect: widely used in medical and office environments; Uniform air volume and strong controllability: meet the needs of balanced heat dissipation or air supply; Accurate control with DC drive: intelligent speed regulation is possible.