Flow Units Water in motion; i.e., flowing in streams, canals, pipelines, and ditches, is measured in units of volume per unit of time—gallons per minute (gpm), cubic feet per second (cfs), acre-inches per hour and acre feet per day. Cubic feet per second, sometimes written second-feet (sec.

In the simplest method, a current meter turns with the flow of the river or stream. The current meter is used to measure water velocity at predetermined points (subsections) along a marked line, suspended cableway, or bridge across a river or stream. The depth of the water is also measured at each point.

The SI unit for flow rate is m3/s, but a number of other units for Q are in common use. For example, the heart of a resting adult pumps blood at a rate of 5.00 liters per minute (L/min). Note that a liter (L) is 1/1000 of a cubic meter or 1000 cubic centimeters (10-3 m3 or 103 cm3).

A Pitot-tube is used to measure fluid flow velocity. The tube is pointed into the flow and the difference between the stagnation pressure at the tip of the probe and the static pressure at its side is measured, yielding the dynamic pressure from which the fluid velocity is calculated using Bernoulli’s equation.

Flow is the volume of fluid that passes in a unit of time. In water resources, flow is often measured in units of cubic feet per second (cfs), cubic meters per second (cms), gallons per minute (gpm), or other various units.

Measurement of flow, whether it is a liquid or gas, is commonly a critical parameter in many processes. In most operations it is important to know that the right fluid is at the right place at the right time. Measuring flow and pressure can provide this security to the process and personnel.

Types of Flow Meters

• Coriolis Meters.
• DP Meters.
• Magnetic Meters.
• Multiphase Meters.
• Turbine Meters.
• Ultrasonic Meters.
• Vortex Meters.

Instructions

1. Collect the Water. Set the timer to 10 seconds. Turn on the cold water full-blast.
2. Measure the Water. Measure the quantity of water in the container, using the measuring cup.
3. Calculate the GPM Flow Rate. Multiply the measured quantity of water by 6 to calculate the flow rate in gallons per minute (GPM).

Magnetic flow meters measure the speed of a fluid passing through a pipe using a magnetic field to measure the volumetric flow. They are based on the principle of Faraday’s Law of Electromagnetic Induction, according to which liquid generates voltage when it flows through a magnetic field.

A: Flow meters are devices used to measure the flow rate of gas, liquid or steam flowing through a pipe. There are many diverse applications that require mass flow measurement, such as natural gas, compressed air, boiler efficiency, burner control, gas mixing & blending, steam flow, and water flow.

We can determine the value of the mass flow rate from the flow conditions. A units check gives area x length/time x time = area x length = volume. The mass m contained in this volume is simply density r times the volume. To determine the mass flow rate mdot, we divide the mass by the time.

inertial flow meter

Volumetric flow rate is a measure of the 3-dimensional space that the gas occupies as it flows through the instrument under the measured pressure and temperature conditions. Mass flow rate is a measure of the number of molecules that flow through the instrument, regardless of how much space those molecules occupy.

The mass flow rate of a system is a measure of the mass of fluid passing a point in the ( ˙ m) system per unit time. The mass flow rate is related to the volumetric flow rate as shown in Equation 3-2 where r is the density of the fluid.

To calculate the drops per minute, the drop factor is needed. The formula for calculating the IV flow rate (drip rate) is total volume (in mL) divided by time (in min), multiplied by the drop factor (in gtts/mL), which equals the IV flow rate in gtts/min.

symbol Q

1 Velocity, speed, flow rate, and acceleration. Velocity indicates the distance and the direction of a motion, and is called a vector quantity. To define a vector quantity, both magnitude and direction are needed.

For transport phenomena, flux is a vector quantity, describing the magnitude and direction of the flow of a substance or property. In vector calculus flux is a scalar quantity, defined as the surface integral of the perpendicular component of a vector field over a surface.

“”Q” is derived from the French word “Quantité” which means “Amount” or Quantity. It was introduced by the French at the time when they dominated science (between the 18th century and the 19th century, ie. Darcy’s law 1856, Poiseuille’s law, 1840). The French word derives from Latin ” Quantitas “.

Explanation: Mass flow rate = m/t, => unit = kg/s, volumetric flow rate = V/t, => unit = Liters/s, molar rate = n/t, => unit = moles/s.

Orificemeter

Hence, coriolis method is used for the measuring liquid flow rate. Explanation: Orifice plate, venture tube and flow nozzle all these devices are used for flow obstruction.

A flow meter (or flow sensor) is an instrument used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas.

The Venturimeter: A Venturimeter is a device meant for measuring the quantity of a liquid flowing through a pipe. In its simplest form, the device consists of a short converging section leading to a throat and followed by a diverging section.

To calculate the water flow (in m3) multiply the average water velocity (in m/s) by the average width (in m) and by the average depth (in m). Water flow = 0.425 m/s x 1 m x 0.6 m = 0.255 m3/s.

Velocity meters measure velocity of the stream to calculate the volumetric flowrate. These are less sensitive when the Reynolds number of fluid is higher than 10000. Velocity flow meters include turbine, paddlewheel, vortex shedding, electromagnetic and sonic/ultrasonic flow meters.