As the electrical resistance of most metals is dependent upon the temperature of the metal ( tungsten is a popular choice for hot-wires), a relationship can be obtained. Air flowing past the wire cools the wire. In addition to the flow rate, the hot wire anemometer can measure the volume flow and the ambient temperature. The Hot-Wire Anemometer features 10 Analog channels, for Hot-Wire or Hot-Film Sensors, with a built-in Signal Conditioner and Filter in each channel. In addition, they are fragile and can be easily damaged. Hot-wire anemometers are very accurate, but they can be affected by the temperature of the air. They work by heating a wire and measuring the change in temperature of the air as it flows past the wire. This guarantees a particularly compact design. Hot-wire anemometry is a technique for measuring the velocity of fluids, and can be used in many different fields. Hot-wire Hot-wire anemometers are the most common type.
Sometimes used with gas chromatography systems, these instruments may be rated for use with flammable and explosive gases. Hot wire anemometers use a fine wire (on the order of several micrometres) electrically heated to some temperature above the ambient. The hot wire anemometer measures the flow velocity according to the hot wire principle. Some flowmeters measure and monitor the flow of gases. In the laboratory, hot wire anemometers can be used to measure outside wind speed, air velocity, and temperature in hoods and enclosures, and slight gas movement in ductwork. In the laboratory, hot wire anemometers can be used to measure outside wind speed, air velocity, and temperature in hoods and enclosures, and slight gas movement in ductwork. The wire is cooled by the air flow and the known resistance of the metal is used to calculate the flow speed.Īlthough somewhat delicate, hot wire anemometers are used to study turbulent or rapid velocity fluctuation flows. Hot wire anemometers use an electrically heated wire to help calculate air speed. Thermal anemometers are also ideally suited to the measurement of unsteady flows such as those that arise behind rotating blade rows when the flow is viewed in. Used with a constant background flow of gas. Digital vane thermoanemometers may be pre-calibrated, traceable to NIST, and offer a choice of measurement units (ft./min., m/s, mph, km/hr., knots, CFM, and CMM). A hot-wire anemometer was evaluated to determine its suitability for measurement of small tidal volumes.
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