Under what flow conditions are closed-pipe flowmeters typically installed?

Closed-pipe flowmeters are typically installed in sections of pipe that remain full under all normal discharge conditions because this allows for accurate and reliable measurements of flow. When the pipe is full, the flowmeter can properly interact with the fluid, ensuring that all of the flow is accounted for. This full condition minimizes issues such as air pockets or turbulence, which can lead to erroneous readings.

In scenarios where the pipe is partially filled or under intermittent discharge conditions, the measurements may not be reliable, as the flowmeter might not experience the flow continuously, or the air-water interface could create inaccuracies. Additionally, low flow rates alone do not justify the installation of closed-pipe flowmeters in such cases; the key requirement is the consistent full condition of the pipe. Hence, the most suitable scenario for the installation of these flowmeters is indeed when the pipe remains full under all normal discharge conditions.