Related introduction of hot wire anemometer
A metal wire is heated by an electric current, and the flowing air dissipates heat. The heat dissipation rate is linearly related to the square root of the wind speed, and then linearized through electronic circuits (to facilitate scaling and reading), a hot-wire anemometer can be made. Hot wire anemometers are divided into two types: side heating type and direct heating type. Side-heated hot wires are generally manganese-copper wires, whose temperature coefficient of resistance is close to zero, and a temperature measuring element is installed on its surface. Direct heating hot wires are mostly made of platinum wire, which can directly measure the temperature of the hot wire itself while measuring the wind speed. The hot-wire anemometer has high sensitivity at small wind speeds and is suitable for measuring small wind speeds. With a time constant of only a few hundredths of a second, it is an important tool for atmospheric turbulence and agricultural meteorology measurements.
What is the construction principle of the thermal bulb electric anemometer?
The construction principle of the hot bulb electric anemometer is that it is an instrument that can measure low wind speed, and its measuring range is 0.05-10m/s. It consists of two parts: a hot ball rod probe and a measuring instrument. The probe has a glass ball with a diameter of 0.6mm, and a nickel-chromium wire ring for heating the glass ball and two series-connected thermocouples are wound around the ball. The cold end of the thermocouple is connected to a phosphor bronze support and is directly exposed to the air flow. When a certain amount of current passes through the heating ring, the temperature of the glass ball increases. The degree of increase is related to the wind speed. When the wind speed is small, the degree of increase will be greater; otherwise, the degree of increase will be smaller. The magnitude of the rise is indicated on the meter by a thermocouple. According to the reading of the electric meter, the wind speed (m/s) can be found by checking the calibration curve.
