The Venturi meter measures flow by detecting a differential reading of which physical quantity across a constricted section?

The Venturi meter measures flow by detecting a differential reading of which physical quantity across a constricted section?

• A. Pressure
• B. Temperature
• C. Density
• D. Humidity

Answer: (A)

The main idea is that a Venturi meter determines flow from the pressure difference created by speeding the fluid through a constricted section. As the fluid enters the narrow throat, its velocity increases, and the static pressure drops. By measuring the pressure on the upstream side and at the throat with taps and a differential pressure transmitter, the device converts that pressure difference into a flow rate. This is why the quantity being read across the constricted section is pressure. Temperature, density, and humidity aren’t what the Venturi reads directly to find flow. They’re properties of the fluid or conditions that can influence the calculation, but the measurement itself is a differential pressure, which is tied to the change in velocity caused by the constriction.

The main idea is that a Venturi meter determines flow from the pressure difference created by speeding the fluid through a constricted section. As the fluid enters the narrow throat, its velocity increases, and the static pressure drops. By measuring the pressure on the upstream side and at the throat with taps and a differential pressure transmitter, the device converts that pressure difference into a flow rate. This is why the quantity being read across the constricted section is pressure.

Temperature, density, and humidity aren’t what the Venturi reads directly to find flow. They’re properties of the fluid or conditions that can influence the calculation, but the measurement itself is a differential pressure, which is tied to the change in velocity caused by the constriction.