The energy balance equation–flow measuring devices
In this lecture, we discuss a few common devices, which are mostly based on the principle of general mechanical energy balance, to measure the volumetric flow rate of a fluid:
Venturimeter
Orificemeter
Pitot tube
Rotameter*
The first three devices are based on the mechanical energy balance. *The last instrument is based on a simple force balance. (a) Venturimeter: it is a simple instrument having a converging–diverging section installed in a pipe. Pressure-drop is measured across two sections and is correlated to the flow rate, accounting for the viscous (minor) loss.
