A Brief Discussion on the Classification and Characteristics of Portable Axial Fans

A Brief Discussion on the Classification and Characteristics of Portable Axial Fans

Today, we will discuss the classification and characteristics of portable axial fans. The main points are outlined below. 1. Portable Axial Fan Sliding Base Since the impeller alone exhibits low pressure and low efficiency characteristics and lacks a rear baffle, the kinetic energy of the outlet wind speed is not utilized. Single-stage portable axial fans have a very low total pressure coefficient, but their construction is simple and they are easy to manufacture. They are primarily used for low-pressure applications, with a specific speed typically ranging from 205 to 490. The hub ratio of the blades is generally smaller. 2. Compressed Movable Axial Flow Fans These fans are equipped with a rear baffle at the rear end of the impeller. The purpose is to partially or fully utilize the vortex generated around the object at the fan outlet to increase the fan’s pressure, thereby improving the fan’s efficiency. This type is characterized by a single-stage design. The pressure coefficient is relatively high, generally ranging from 0.15 to 0.72. Due to its very high efficiency, this type of impeller is widely used in axial flow fans. The specific speed of this type of axial flow fan is typically 90–505. By adjusting the installation angle of the propeller blades, the operating conditions can be adapted to suit specific requirements. 3. Front Diffuser + Propeller Impeller This type of axial flow fan features a front diffuser fixed at the front end of the impeller. The blade installation angle can be adjusted to generate a negative rotational velocity at the impeller inlet, while the rotational velocity at the impeller outlet remains zero. The front diffuser causes the propeller to deteriorate. The inlet airflow velocity field and pressure field increase the average relative velocity of the propeller, thereby increasing fan losses and reducing efficiency. Additionally, this type of axial flow fan also produces higher noise levels. 4. Front Diffuser + Reflector + Rear Diffuser In this type of adjustable axial fan, the installation angle of the front diffuser blades is designed to be adjustable. A characteristic of this type of fan is its high pressure; the total pressure coefficient of a single-stage fan is approximately 0.33. 0.84; the blade adjustment mechanism is simple, easy to adjust, and can be automated. Since adjustments can be made by changing the installation angle of the impeller blades, the operational performance of the axial flow fan is improved. The drawbacks are that the overall axial dimensions of the fan are relatively large, and noise levels are relatively high.