Mass flow rate vs Volumetric flow rate is what we must use in flow measurement and control. In this post, we compare the concept of volume flow and mass flow and the conversion between the two.

Mass Flow Rate vs Volumetric Flow Rate

Commonly used flow meters, such as orifice plates. Turbine flowmeter. Vortex flowmeter. Electromagnetic Flowmeter. Rotameter. The flow measurement value of ultrasonic flowmeter and oval gear flowmeter is the volume flow of fluid. Coriolis mass flow meters and thermal gas mass flow meters measure mass flow.

Sino-Inst offers a variety of volume flow and mass flow meters for flow measurement. If you have any questions, please contact our sales engineers.

What is Flow Rate?

Flow rate refers to the ratio of the amount of fluid flowing through the cross-section of the pipe to the time it takes for that amount to pass through the cross-section. Flow is divided into volume flow and mass flow.

What is volume flow?

The volume flow rate is the flow rate expressed by the volume of the fluid quantity.
The volume flow is expressed by the formula: qv=V/t=u×A.
In the formula: qv is the volume flow, m3/s.
V is the unit flow volume, m3.
t is the unit time, s.
u is the average flow velocity in the pipe, m/s.
A is the cross-sectional area of ​​the pipeline, m2.

Among the commonly used flow meters, such as orifice plates, turbine flow meters, vortex flow meters, electromagnetic flowmeters, rotameters, ultrasonic flow meters, and oval gear flow meters, the flow measurement value is the volume flow of the fluid.

Featured Volume Flow Meters

What is mass flow?

Mass flow rate refers to the flow rate of fluid quantity expressed by mass.
The mass flow rate can be expressed by the formula: qm=m/t=ρ×u×A.
In the formula, qm is the mass flow rate, kg/s.
m is the unit fluid mass, kg.
ρ is the fluid density, kg/m3.
t is the unit time, s.
u is the average flow velocity in the pipe, m/s.
A is the cross-sectional area of ​​the pipeline, m2.

Featured Mass Flow Meters

Volumetric flow rate to Mass flow rate

  1. If the mass flow of the flow is known and needs to be converted into volume flow, the following formula can be used: qv=qm/ρ. In the formula, qv is volume flow, m3/s. qm is mass flow, kg/s. ρ is fluid Density, kg/m3.
  2. If the volume flow rate of the fluid is known, it needs to be converted into a mass flow rate, which can be done with the formula: qm=qv×ρ.

How to convert air volume flow to air mass flow?

The conversion factor between air volume flow rate and air volume flow rate is 1.29. That is, to convert the volume flow of air into the mass flow, multiply the coefficient by 1.29.

Solution: Let the mass of air passing in t hours be m kg, the volume be V cubic meters, and the known air density ρ = 1.29 kg/m3.

Then the volume flow rate of the air qv=V/t (cubic meters/hour), and the mass flow rate qm=m/t (kg/hour).

And because air quality = air density x air volume, m = ρV = 1.29V.

Then qm=m/t=ρV/t=ρqv=1.29qv.

That is, to convert the volume flow of air into a mass flow, multiply the coefficient by 1.29.

Density, Mass Flow, and Volumetric Flow

A description of the relationship between density, mass flow rate, and volumetric flow rate. The following video provides a good explanation.

Video source: https://www.youtube.com/watch?v=4KNfADc77XU

Volume flow unit converter

UnitL/minm3/hf t 3/hUkgal/minUsgal/minUS  bbl/d
L/min10.062.11890.219970.02641889.057
M3/h16.667135.3143.6674.403151
Ft3/h0.47190.02831710.10380.12474.2746
Ukgal/min4.5640.027279.632511.2003241.1
Usgal/min3.7850.22738.02080.8326134.28
US
bbl/d
0.11040.006240.233940.024280.029171

FAQ

How do you convert volumetric flow to mass flow?

If the volume flow rate of the fluid is known, it needs to be converted into mass flow rate, which can be carried out by the formula: qm=qv×ρ

How do you calculate the volumetric flow rate?

Volume flowrate (Volume Flowrate) is the volume of fluid passing through the flow section per unit time, referred to as flow rate, expressed by Q.
Flow rate expressed in volume/time or volume/time. Such as: m³/h ,l/h.
Volume flow rate (Q) = average velocity (v) * pipe cross-sectional area (A)

Does volumetric flow rate change with pressure?

The fluid pressure and flow rate in the pipeline are completely two concepts. For fluids with high pressure, the flow rate can be high or low.
Engineering pressure is the amount of force per unit area. The flow rate is the amount (weight or volume) of the fluid flowing through the pipe per unit time.
Here, there is another important parameter: flow rate. It is the average velocity of fluid flowing in the pipe. The unit is: the flow rate per unit area (internal section of the pipeline). That is: the flow rate multiplied by the pipe cross-sectional area equals the flow rate.
If the fluid is a gas (compressibility), the flow rate is constant, and the flow rate of a gas with high pressure is of course also large. If the size of the pipe is constant, the flow rate of the fluid with a large flow rate is of course also large; the pressure loss (i.e. pipeline resistance) is proportional to the square of the flow rate, that is, proportional to the square of the flow rate.
If the fluid under a certain pressure is directly discharged to the atmosphere under certain conditions (the diameter of the pipe is the same), the fluid pressure can be converted into velocity energy, and the flow rate of the fluid with high pressure is correspondingly high, and of course, the flow rate is also large.

You may like:

Bidirectional Flow Measurement

Can the flow meter perform bidirectional measurement? If the flow direction of the medium in the pipeline is reversed. Does the flow meter need to be installed with a flow meter for forwarding use and a flow meter for reverse Read More

What is Modbus Protocol?

Modbus Protocol Features The main reasons why Modbus is more widely used than other communication protocols are: Published publicly and without copyright requirements Easy to deploy and maintain For suppliers, there are not many restrictions on modifying mobile local bits Read More

Guide: Magnetic Flowmeter Installation

Step 1: Magnetic Flowmeter Installation environment requirements In order to make the electromagnetic flowmeter work stable and reliable, the following requirements should be paid attention to when choosing the installation location: Try to avoid ferromagnetic objects and equipment with strong Read More

Solvent flow meters

Solvent flow meter – Oval Gear An Oval Gear flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive Solvent fluids. High measurement accuracy; The installation pipeline Read More

Grease Flow Meters

Industrial Grease Flow meters are different from grease guns or grease meters. Industrial Grease Flow meters need to deal with more complex conditions. The pipe diameter can range from DN10 to DN200, or even larger. So how to choose the Read More

What is Flow Meter K-factor? And how to calculate?

The flow coefficient of the flowmeter refers to the proportional relationship between the measured flow and the flow of the standard device under certain conditions. The Flow Meter K-factor is given by the manufacturer when it is calibrated. The K Read More

How to Select Ultrasonic flow detectors?

Ultrasonic flow detectors types Ultrasonic flow detectors can be divided into external paste type, insertion type, and pipe section type according to the installation method. A) Clamp-on type External paste type ultrasonic flowmeter is produced earlier, the user is more Read More

Irrigation Flow Meters for Agriculture Water System

Agricultural irrigation water system It consists of irrigation canal head project, water transmission and distribution project and field irrigation project. ①Irrigation canal head project has reservoirs, pumping stations, dammed diversion projects, damless diversion projects, wells and other forms. Used to Read More

Technical Guide – Thermal mass flow meter

Thermal mass flow meter working principle Thermal gas mass flow meter is designed on the basis of thermal dispersion. And adopts method of constant differential temperature to measuring gas flow. It has advantages of small size, easy installation, high reliability Read More

Sino-Inst, Manufacturer for Flow Meters, like gas vortex flow meter, liquid vortex flow meter, sanitary flow meter, insertion flow meter, steam flow meter, and natural gas flow meter.

Sino-Inst’s Flow Meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.

Please provide your measurement parameters or details. Sino-Instrument support customer customization and OEM
Please provide your measurement parameters or details. Sino-Instrument support customer customization and OEM

Leave a Reply

Your email address will not be published. Required fields are marked *