Axial Fans

What Is an Axial Fan?

An axial fan is a type of mechanical fan. Its name describes the direction that fluids flow through it.

These designs will be familiar to most people as box fans, computer case fans, window fans and many other types. These fans create airflow that runs parallels to the rotating shaft on the fan. They are highly controllable, and not only the speed of the fan but the direction of the flow can be precisely directed. They are heavily used in industry and the size range available is significant. They range from very small fans, some of which are designed so that a person can hold them in their hand for personal cooling, to enormous fans used in industrial facilities and for scientific purposes.

Axial fans have several advantages that make them desirable compared to other options, such as centrifugal fans, for certain applications. For the amount of fluid they move, for instance, they are very quiet. A centrifugal fan may actually provide better cooling in a computer case, for example, but the increased noise would likely outweigh any benefits. Axial fans can also be added to cases with minimal modifications, while other options—including water-cooling systems—are bulky and expensive.

This combination of good performance, long lifespan and affordability makes axial fans very common in many areas of life. Households commonly have more than one, as they provide an excellent solution to heating and cooling needs, allowing refrigerated, evaporative cooled or heated air to be directed around a house for temperature management. They also allow air from windows and air inside the house to be moved without being cooled or heated, providing an economical alternative to air conditioning in hot areas.

Axial fans are used heavily in industry, where very large floor fans, duct fans or exhaust fans may be largely responsible for maintaining the interior air quality of a facility. This makes them vital equipment for factories, warehouses and other large spaces where air needs to be circulated. Some of the fans used in these applications are very large, designed to keep air flowing through extensive ducting systems or circulate a huge volume of air.

The electric motors that drive axial fans can be controlled easily, allowing higher and lower rpms to be selected, direction of flow to be changed and other variables to be changed, providing a significant degree of control.

 

Out of Which Parts Is an Axial Fan Manufactured?

Axial fans are made out of relatively simple parts, but the engineering that goes into them can be very advanced. For example, subtle differences between one fan and the next, such as a different orientation of the blades, can drastically change airflow or and other qualities.

The basic parts include the motor, which rotates the shaft and, in turn, the blades. The fan, shaft and the blades are contained within housings, generally with guards to protect against having a body part enter or someone actually falling into the spinning blades. Electronic switches and sometimes digital interfaces are used to control the operation of most fans.

Fans designed to be mounted in computer cases, windows and walls usually have a design that includes extra material used for that mounting. Most computer fans, for example, have holes tapped on the edges of them so that they can be fit into computer cases if extra cooling needs to be added for a machine.

The blades on axial fans are highly engineered products, but the other parts are generally very durable and not particularly expensive. Electric motors, for example, are reliable, efficient and long lasting, in addition to being inexpensive. Axial fans are used in many different applications, and different applications call for different features and different designs.

Axial fans can be made in very compact designs. This makes them ideal for cooling not only computer cases, but actually cooling specific components within a computer case. For example, processors and video cards oftentimes have their own axial fan cooling system built into them, given the enormous amount of heat that such components can produce.

Where the blades are concerned, they can be made so that they are pointed toward the rotation of the fan, against the rotation of the fan or axially to the rotation of the fan. This impacts airflow and sophisticated systems have to take this into account. For applications such as everyday box fans or other household fans, it may not make a great deal of difference.

 

How Does an Axial Fan Function?

The name of an axial fan precisely describes its function. The fan blades rotate around the shaft, powered by the electric motor. The rotating blades function as a propeller. This creates airflow when the rotation of propeller lowers the air pressure behind it, sucking the air into the propeller parallel to the shaft.

In terms of human comfort, this creates a wind chill that can make a room seem cooler on hot days.  Fans can also be used to direct heated or cooled air into a room.

For machinery, they offer a precise way to direct airflow onto or around parts that need to be cooled. Axial fans can also be used to influence the pressure in an environment. This is clearly demonstrated in cooling systems for computer cases. Some builders will set up the fans so that air is being sucked in from the outside faster than it’s being discharged from the inside, resulting in positive pressure. Other builders will try to evacuate as much air from the case as possible, resulting in negative pressure.

In a household and in industrial settings the working of an axial fan can be very dramatic. Whole house fans, for instance, are cooling solutions for homes that are much more efficient than air conditioning and that work by creating a continuous airflow through the entire house, cooling it off very effectively.

Axial fans can suffer diminished performance from stalling and surging. Stalling occurs as an interruption in the flow of air across the fan. Surging is just the opposite. In complex ventilation systems, fans have to be set up in a way that ensures that they don’t cause stalling problems.

Poorly built fans may be subject to issues with vibration, which could have significant consequences if the fans are installed on sensitive equipment.

 

Which Companies Produce Axial Fans?

Some large manufacturers offer fans among their other products. There are also speciality companies that produce fans as their mainstay business. Fans are continually in demand among consumers, industry and scientific sectors.

 

ARX

This manufacturer specializes in thermal control, with a wide range of ceramic fans, blowers and other devices.

 

Bud

This company makes enclosures, fans and other products for industrial uses.

 

COMAIR ROTRON

Vale assemblies, fans and blowers are all available from this manufacturer, which has a global reach.

 

Copal Electronics

Copal Electronics makes electronic components and mechanical components.

 

ebm-papst

This is a global company known for their axial fans and for electric motors.

 

Global Fans

Ventilators, ceiling fans and many other types of fans are available from Global Fans, suitable for household and industry use.

 

Micronel

This company offers man different fan designs and thermal control devices.

 

Orion

AC and CD fans, as well as fans designed for speciality uses, are all available from this manufacturer.

 

RS

A global electronics distribution company, this UK based entity has numerous different fans available on the market.

 

Sanyo Denki

A Japanese company that has many different fans, motors, other types of cooling systems and more on the market.

 

Schneider Electric

This is a very old, global company that produces many different components and products, including fans.

 

Sunon

Sunon is a speciality company that focuses on fans. They have many different designs available and have won awards for some of their products.

 

What Is Considered the Air Flow of an Axial Fan?

Airflow is measured in cubic meters per hour and describes the expected amount of air that will flow through the fan in one hour’s time. In complex systems, there may be many fans working together to get a desired airflow. Axial fans can also be installed in different locations and set up so that airflow is directed smoothly through a space, or so that the space has positive or negative pressure due to the working of the fans.

 

Which Series of Axial Fans Exist?

There are many different series of fans designed and marketed by various manufacturers. The series numbers include numerical ones, like the 3400N series of computer fans from ebm-papst or the Maglev series from Sunon. Some of the popular series include KDE, CeraDyna and OD1238.

 

What Is the Fan Speed?

Fan speed is measured in rpms and describes the speed at which the propeller rotates. This is variable on many models fans and, in fact, the axial fans used in computers are designed to be variable speed to cut down on a nuisance factor of high rpms: noise.

Some fans rotate at incredibly fast speeds, as high as 40,000 rpm in the case of the Micronel F40 series.

Fan speeds tend to be directly related to fan size. Larger fans move more air and, because of that, they can oftentimes be run at lower rpms than smaller fans to move the same quantity of air. For applications where a user is going to be next to a machine that requires fan cooling, putting larger fans in the device sometimes allows for proper cooling with less noise than smaller fans would generate.

 

What Is Considered AC or DC Operation of an Axial Fan?

This simply indicates whether the fan runs on AC or DC power.

 

Which Bearing Types Are Available for Axial Fans?

The bearing types available for axial fans include ball, sleeve, CeraDyna A and CeraDyna C; Sintec, Sleeve and Vapo. The bearing quality has a significant impact on the lifetime of the fan, so some manufacturers advertise their offerings heavily. The CeraDyna bearing system is one of the points on which the manufacturer markets fans, for instance.

 

What Does the Direction of Curve Define?

The direction of the blades in relation to the rotation of the fan is described as the curve. In a forward curved fan, for instance, the blades are oriented in the same direction as the rotation of the fan. In some cases, very engineered systems may require a specific curve direction for the fan. This may not be much of a factor in less demanding applications, however.

 

What Is the Power Consumption of an Axial Fan?

The power consumption of an axial fan is one of its most desirable features. This describes the amount of power required to run the device in watts. Axial fans are enormously efficient to operate.

 

How Is the Noise level of an Axial Fan Defined?

All fans make some noise. This is measured in decibels (dB) and expresses the amount of noise the fan generates during normal operation. This is a concern where both large and small fans are being installed. Small fans rotating at high rpms can generate a great deal of noise, for instance, a problem for powerful computers that require a great degree of thermal management. Larger fans can also generate a great deal of noise, in some cases. Poorly engineered fans may have problems with vibration, which can increase the amount of noise they generate.

 

Which Sensor Output Types Exist for Axial Fans?

Sensor outputs on fans are important in applications where flow has to be precisely controlled, such as in computer cases. Fans are outfitted with many different types of sensors, including tachometers, voltage outputs, temperature outputs, open collectors, which provide rpm data.

Some fans can be very precisely controlled via software. Computer fans can usually have their speeds set manually by the user, which some programmers and other demanding users take advantage of to make sure their computer is being cooled as much as possible at all times.

 

Which Blade Diameters Are Available for Axial Fans?

Blade diameters range from a few millimetres and up. It is simply the diameter of the propeller element of the fan

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