# Venturi Tube Flow Rate

on . Posted in Fluid Dynamics

Venturi tube, also called Venturi meter, is a device used to measure the flow rate of a fluid, typically a liquid, in a pipeline.  It operates on the principle of the Venturi effect, which is a reduction in fluid pressure when it flows through a constricted section of a pipe.  This pressure drop is related to the flow rate of the fluid and can be used to calculate the flow rate.  The Venturi tube consists of a tapered section within the pipe.  As the fluid flows through the narrow throat of the Venturi tube, its velocity increases, and the pressure decreases.  This change in pressure can be measured using pressure sensors located at different points along the tube.

The flow rate through a Venturi tube can be calculated using the Bernoulli's equation, which relates the pressure, velocity, and density of the fluid at two points in the tube.  The velocity at the throat is typically higher than at the inlet because of the narrowing of the tube.  By measuring the pressure difference between these two points, along with other factors such as the fluid properties (density), you can calculate the flow rate through the Venturi tube.

Venturi tubes are widely used in various industries to accurately measure fluid flow rates, especially in situations where precise measurements are required for industrial processes, fluid transport, and control systems.  Calibration and accurate measurement of pressure and temperature are crucial for obtaining reliable flow rate readings.

### Venturi Tube Flow Rate Formula

$$Q = C_v \; A_c \; \sqrt{ 2 \; g \; h_l }$$
Symbol English Metric
$$Q$$ = volumetric flow rate / flow rate $$ft^3\;/\;sec$$ $$m^3\;/\;s$$
$$C_v$$ = flow coefficient $$dimensionless$$
$$A_c$$ = area cross-section $$in^2$$ $$mm^2$$
$$g$$ = gravitational acceleration $$ft\;/\;sec^2$$ $$m\;/\;s^2$$
$$h_l$$ = head loss $$ft$$ $$m$$

### Venturi Tube Flow Rate Formula

$$Q = C_v \; A_c \; \sqrt{ 2 \; p_l \;/\; \rho }$$
Symbol English Metric
$$Q$$ = volumetric flow rate / flow rate $$ft^3\;/\;sec$$ $$m^3\;/\;s$$
$$C_v$$ = flow coefficient $$dimensionless$$
$$A_c$$ = area cross-section $$in^2$$ $$mm^2$$
$$p_l$$ = pressure loss $$lbf\;/\;in^2$$ $$Pa$$
$$\rho$$ (Greek symbol rho) = density $$lbm\;/\;ft^3$$   $$kg\;/\;m^3$$

Tags: Flow Pipeline