Hot Wire Anemometers – Everything You Need to Know

When you need to know the velocity of air in a particular atmosphere, a hot wire anemometer could be just what you need. This simple bit of kit offers fast and accurate results ideal for assessing environments and climates. Want to know more about how a hot wire anemometer works? You’re in the right place.   

What is a hot wire anemometer used to measure?

Hot wire anemometers can be used to measure air velocity and temperature. They can be used to measure a variety of gases and fluids and is useful for checking the climate of a space or area. Many hot wire anemometers also contain a temperature sensor, allowing for a more complete picture of the environment.  

How do hot wire anemometers work?

There are several different hot wire anemometer designs, but the majority consist of two probes with a tungsten, platinum or platinum-iridium wire stretched between them on constant-temperature circuit versions of an anemometer, a glass-coated thermistor bead may be included.  

Hot wire anemometers work by sending an electric current through the wire. This current causes the wire to heat up. When a gas or fluid (typically air) passes over the device, it will cool the wire. This cooling process indicates the presence of movement energy and the amount of time it takes the wire to cool, makes it possible to determine the velocity of the fluid as it passes over the wire.  

Applications of a hot wire anemometer

The most common applications of a hot wire anemometer are in determining the co-relation between temperature and velocity in turbulent flow. They can be used as a research tool for fluid mechanisms and are often employed as a way to analyze conventional, turbulent, and laminar boundary layer fluid flows.  

How to use a hot wire anemometer

Hot wire anemometers are typically very easy to use. All you need to do is hold the probe freely in the fluid or air flow that is to be tested, while the anemometer is switched on. The result is normally displayed digitally on the instrument itself, or it may be transferred to an external screen or source, when it has the appropriate software. The result is typically retrieved very quickly, within a matter of minutes in most cases.  

Advantages of a hot wire anemometer

There are a number of advantages to hot wire anemometers when compared to other methods of measuring air velocity, including: 

• Their size. Hot wire anemometers can be very small, which reduces the disturbance caused to the air flow that is being measured.  
• The wire also has a small time constant, which means that hot wire anemometers are very sensitive to rapid changes in velocity.  
• Hot wire anemometers typically have excellent frequency response characteristics and high spatial resolution. 
• They are also normally very easy to use.  

Disadvantages of a hot wire anemometer

As with any testing instrument, there are potential downsides to consider too. Disadvantages of hot wire anemometers include: 

• Because hot wire anemometers use a very thin wire, there are constraints to the wire’s physical strength. 
• Hot wire anemometers can be affected by the values of atmospheric temperature, so this must be accounted for in the resulting calculation.  

Hot wire anemometers at Industrial Physics

With our years of expertise and highly knowledgeable engineers, we have developed an easy to use, fast and accurate hot wire anemometer.  

TQC Sheen Hot Wire Anemometer  

This handheld device ideal for low air velocity and volume measurement. It has a built-in temperature probe that measures air temperature in C° or F° and it also measures the air velocity in m/s, km/hr, ft/min, MPH and Knots, offering you a comprehensive reading of the air in your location.  

If you are looking for a complementary, handheld instrument that can also test the humidity of the air, then we recommend our TQC Sheen Thermo Hygometer, which accurately measures vapor in the air to return reliable results.  

Help from the experts: climate testing and more

When you need to assess the air condition in a specific place, whether that’s because you are carrying out climate-sensitive tests to assess paint drying capabilities or you need to know how a coating will dry at a specific temperature, we can help. From the TQC Sheen Hot Wire Anemometer to our full range of climate testing equipment, we develop test and measurement solutions to meet your needs – no matter how big or small.