anemometer and the difference between high temperature anemometer

anemometer, the working principle of thermal probe is based on the impact of cold air take away heat, heat element with the aid of a switch, to maintain a constant temperature, the adjusting current and flow rate is proportional to the relationship. When used in turbulent thermal probe, from all directions of air flow and heat shock element, which would affect the accuracy of the measurement results. Measurement in turbulent flow, the thermal anemometer, the velocity sensor is often higher than the value of the wheel probe. The above phenomenon can be observed in the process of pipe measurement. According to different design management of turbulent flow in pipe, even at low speeds. Therefore, anemometer measurement process should be performed in the linear section of the pipeline. Starting point of the straight line part should be at least 10 before the measurement point; D( D = pipe diameter, the unit is CM) Outside; The finish at least after the measurement point 4; D. Fluid section shall not have any shade. ( Edges and corners, the heavy suspension, content, etc. )

the propeller anemometer probe

the propeller anemometer sensor working principle is based on the rotation is converted into electrical signals, after a close first induction, beginning to count the rotation of the wheel and generate a pulse series, then through detector conversion processing, can get the speed value. Large diameter probe anemometer ( 60mm,100mm) Suitable for the measurement, small velocity of turbulent flow, As in the pipeline export) 。 Anemometer probe more suitable for measurement of small diameter pipe cross section is greater than the first adventure changed cross-sectional 100 times more air

hot wire anemometer description

hot wire anemometer ( Hot wire Anemometer, HWA) , invented in the 1920 s. Its basic principle is a thin metal wire in a fluid, the flow of electricity heating wire, make its temperature is higher than the temperature of the fluid, so the wire is called the hotline. When the fluid flows through the wire along the vertical direction, will take away part of the metal wire heat, temperature drops make wire. Been derived according to the theory of forced convection heat transfer, the hotline dissipating heat Q and the relation between fluid velocity v ( D3. 4. 4a)

type called gold ( l V。 王,1914) Formula, R, I respectively hotline resistance and flow of electric current intensity, & Delta; T for the hotline and fluid temperature difference, A and B is related to fluid and thermal physical constants. Considering the resistance temperature properties of the hotline, ( D3. 4. 4a) Type can be turned into ( D3. 4. 4b)

on the type of U for the hotline of output voltage, and B’ Is associated with the temperature coefficient of resistance of hot line of physical constants, be determined by experiment. So by measuring the voltage at the ends of the hotline, you can determine the flow velocity.