PERFORMANCE AND TESTING OF FANS

The performance of the fan, as well as the testing of airflow and volume, air pressure, and fan motor power

The performance of any fan, whether it is centrifugal or not, is determined by three aspects that are interconnected with one another:

Airflow refers to the amount of air that will be moved by the fan in a specific amount of time.

Pressure refers to the amount of power that is required to move air from one area to another, and how much or how little power is required?

The amount of power that is required to generate the pressure that is necessary to move the air is not specified.

Take a more in-depth look at these different factors, shall we?

In the context of a fan or blower, airflow refers to the movement or circulation of air that is induced. The most common way to quantify it is in terms of volume per unit of time, such as cubic meters per hour (m3/h) or cubic feet per minute (CFM). 

The flow of air in fan engineering is affected by a number of factors, including the following:

The form and dimensions of the fan

maximum speed at which a fan's impeller rotates

how the impeller blades are shaped and how big they are

The force or pressure that the fan is operating against in order to do its work.

Individually and collectively, these characteristics have an impact on the fan's capacity to circulate air in an effective and efficient manner. When it comes to fan engineering, having a solid understanding of the concept of airflow is absolutely necessary because it is a fundamental characteristic that has a significant impact on the performance, efficiency, and design of fans for all applications. With the use of airflow calculations and performance curves, we are able to determine the most suitable fan size and type for your particular application. This is accomplished by taking into consideration factors such as the required airflow rate, the pressure requirements, and the efficiency.

A graph illustrating the different degrees of airflow and pressure caused by MR fans.

It is possible to define air pressure as the force that is exerted by air against a surface that is perpendicular to the direction in which airflow is passing through it. When air is forced to go through a fan, duct, or system, it encounters resistance or opposition, which is reflected by this term. When it comes to airflow resistance, a higher air pressure often indicates a stronger resistance, whereas a lower air pressure typically indicates a lower potential for resistance. Air pressure can be broken down into three categories:

The importance of static pressure cannot be overstated. The pressure of air (in a duct or system) when it is not moving or in motion is referred to as the static pressure.

There are a number of locations within a duct or system where static pressure can be recorded. These locations include before and after a fan, bends or elbows in the ducting, and other points of limitation of the system. Pressure drop, also known as pressure loss, is a significant measurement that is utilized in the process of evaluating the output and efficiency of a fan system. It corresponds to the difference in static pressure that exists between two different locations.

The pressure that is produced by the movement of air is referred to as dynamic pressure, which is also referred to as velocity pressure. Flowing air has a certain amount of kinetic energy, which can be measured by this pressure. Specifically, it is utilized for the purpose of calculating the dynamic consequences of air flow, which includes the impact of velocity on duct design, fan selection, and overall system performance.

The sum of the static pressure and the dynamic pressure of the air is referred to as the total pressure. The overall energy of the air traveling through a duct or system is what it refers to. Because it indicates the overall resistance that the fan must overcome in order to move air through a system, overall pressure is an important parameter in fan engineering. This is because it is a reflection of the overall pressure.

MEASURING THE COVERAGE OF AIR

If you think of it in terms of pounds per square inch (PSI) or bar, for instance, the amount of air pressure that is necessary to fill a car tire, you are essentially using a sledgehammer to shatter a nut. The pressures of the air that we need to test are significantly lower. Therefore, we make use of:

(mmWg) stands for millimeters of water gauge.

The water gauge measuring in inches (in.wg)

Millimeters of water gauge (mmWg) and inches of water gauge (in.wg) are both units of measurement that indicate the pressure that is exerted by a column of water that is of a particular height. When there are only little variations in pressure, these units are utilized for the purpose of measuring low air pressures. The units of measurement mmWg and in.wg are frequently utilized in the field of fan engineering due to the fact that they provide a convenient and practical method for measuring low air pressures with precision and accuracy. The comprehension of these units is not difficult. They find application in gauges and manometers that operate at low pressures.

An electrical test performed on an industrial fan

OUR METHODS FOR EVALUATING FANS

The engineering and research and development department is responsible for conducting fan testing; nevertheless, the outcomes of this testing have an impact on the work of the entire team, notably the design engineers, technical engineers, planning engineers, technicians, prototype engineers, and electrical engineers. With relation to the following, the tests are carried out:

The quality management standard ISO 9001

ISO 14001, which stands for environmental management systems

The ISO/IEC 80079-34 standard addresses the implementation of quality management systems in the production of EX goods.

There are two different kinds of test rigs that our specialists use in order to determine the airflow at either the input or the outflow sites:

Utilizing pressure readings taken 1 x duct diameter and 0.5 x duct diameter away from an in-duct orifice plate (D and 0.5D), the flow rate is estimated using the Inlet Side Test Rig. This is done in compliance with the ISO 5801 standard for industrial fans. In order to accommodate the flow range of the various fan units, it is necessary to have orifice plates of varying diameters. When determining the static pressure of the fan, an inlet side test chamber is utilized for the purpose.

Discharge Side Test Rigs: Once more, the flow rate is monitored by means of an in-duct orifice plate that is equipped with pressure sensors at D and 0.5D (ISO 5801). Once again, orifice plates of varying diameters are utilized in order to successfully cover the flow range of the various fan units. In order to determine the static pressure of the fan, a duct that is proportional to the fan discharge is utilized.

An engineer from ACI is now putting an industrial fan through its paces.

In every circumstance, the tests consist of the following:

the temperatures of the atmosphere and the surrounding environment

taking a series of pressure, temperature, and electrical current measurements as the fan pressure is varied between zero, which is the position at which the fan delivers the largest volume, and the point at which the fan moves no air and creates the maximum pressure.

calculating performance using the formula that has been accepted by the BS

For the sake of this analysis, the data are shown as a static pressure curve, with the X-axis representing flow and the Y-axis representing pressure.

By determining the precise performance of fan designs, our engineers are able to provide the most suitable solution for the specific system requirements of each unique customer. Additionally, they are able to identify possible areas for development in each fan design. Through careful monitoring of airflow, pressure, and power, we are able to determine how much money you would save by installing a new air delivery system and when you would see a return on your investment. In many situations, it is a no-brainer in terms of return on investment (ROI) — your new system might pay for itself in a few of months without any more investment.

THE FACTORS THAT MAY AFFECT THE OUTPUT AND EFFICIENCY OF FANS

Each individual consumer and application is one of a kind due to the fact that there are numerous factors that influence fan performance. When we are developing the system that is best suited to meet your requirements, we take all of these factors into consideration. The specifications of the fan, which include the motor speed, impeller design, volute casing dimensions, and input and discharge point sizes, are not the only factors to consider. One other consideration is that:

the flow resistance of the system, within which the fan will be located and operating

the geographical location of the place (including the temperature of the air, climate, seasonality, and humidity).

the height above sea level, which has an effect on the density of the air.

We are also able to examine customer equipment for any potential flow resistance that may be generated by ducting or other system resistances thanks to our specialized fan testing facilities. Especially if you are currently making use of what is ostensibly 'free' compressed air, our engineers are able to aid you in significantly reducing the amount of money that you spend on air supply applications. Compressed air is not free; it consumes a tremendous amount of energy and is thus very expensive. The reality is that compressed air is not totally free.

Tests are being performed on the fan before it is shipped out.

OBTAIN TECHNICAL ADVICE FROM EXPERTS IN THE AREAS OF FAN PERFORMANCE AND TESTING

Get in touch with the fan engineers at ACI to receive knowledgeable guidance on how to solve the fan engineering issues you are experiencing. Because of our meticulous testing, we are able to provide you with assistance in selecting the appropriate fan for your application. on the investment you made.