Ultrasonic flowmeter relies on the propagation of ultrasonic waves in the flowing medium to record the flow rate information of the fluid, and the received ultrasonic waves can detect the flow rate of the fluid, and then convert it into the flow rate.
The ultrasonic flowmeter calculates the speed and flow of the fluid according to the time difference between the propagation of the ultrasonic wave in the forward direction and the reverse direction in the liquid.
The sensors in the upstream and downstream of the measurement will simultaneously emit ultrasonic pulses, one is propagated upstream and the other is propagated upstream. The propagation speed of the ultrasonic pulse in the forward flow is faster than that in the reverse flow. Because the actual distance of the two pulses is the same, the difference of the transmission time directly reflects the size of the fluid velocity. The larger the time difference of the two ultrasonic pulses, the larger the flow rate.
θ is the Angle between the acoustic beam and the flow direction of the liquid, M is the number of linear propagation of the acoustic beam in the liquid, D is the diameter of the pipe, T1 is the propagation time of the acoustic beam in the positive direction, T2 is the propagation time of the acoustic beam in the reverse direction, ΔT is the time difference, ΔT = T1 -- T2.