it is depends on the type of fluid

Mass flow (also known as mass transfer) is the movement of liquids under pressure or gradient temperature. This includes, inter alia, fluid dynamics and biology. Examples include circulatory system, water transfer in vascular tissues. The flow of the mass should not be confused with the propagation that depends on the concentration gradients within the medium instead of the pressure gradients of the medium itself.

Dear Pisipaty Srinivas Kishore ,

Coriolis flow meter is an optimal instrument to measure the mass flow rate of liquids, gases and even two-phase flow. It does not depend on any physical property of the fluid like density, viscosity, conductivity, etc.

Electromagnetic flow meter is also an accurate instrument but it valids for electrically conductive liquids.

Ultrasonic flow meter can be used also with good accuracy. The fluid to be measures is preferred to be unfiltered, because the principle of ultrasonic flow meter depends on the impurities in the fluid.

Best Wishes,

Muneer

As Mr. Jubear indicated, the answer is fluid-dependent, as well as a function process variables like temperature and pressure. Coriolis can be very good, though I would take exception to their applicability for two-phase flow (wet gas, maybe, with a Lockhart-Martinelli number of less than 0.3, but even that can be problematic under many conditions). Plus, they are very expensive.

Differential producers (orifice, venturi, flow nozzle, etc.) are very good in these types of applications, provided the secondary instrumentation (flow transmitters, density calculation algorithms - integral to coriolis and other types of meters - and so on) is properly calibrated.

Though there is more to the set-up of a DP meter, it provides a degree of reliability that other metering technologies have difficulty attaining.

Thanks to Abbas J. Jubear, Afraa Ibrahim, Muneer Ismael and David Wyatt for adding such a good answers. Further answers on mass flow rate measuring instruments be continued.

Different instruments like venturimeter, orifice meter etc. are fitted to experimental set up to determine mass flow rate of fluid. Venturimeter gives high accuracy in measurement of mass flow rate of fluid.

Another option is using an ultrasonic flow meter which is a clamp on instrument. The advantage is, that the flow can be measured from outsite the pipe system without influencing the flow itself. The accuracy depends on the parameters (sound velocity, temperature, pipe diameter, pipe material, wall thickness...) you feed the instrument with. Further information can be found here:

https://www.pce-instruments.com/us/measuring-instruments/test-meters/flow-meter-pce-instruments-ultrasonic-flow-meter-pce-tds-100hs-incl.-iso-calibration-certificate-det_5841285.htm

Thank you @Benjamin Senger for your answer.

Nice discussion

It was found that venturimeter is used to measure accurately the mass flow rate of fluid out of the instruments like orifice meter, since coefficient of discharge for venturimeter varies in between 0.96 to 0.99.

To measure mass flow rate of fluid there are venturimeter, orifice meter etc. Out of which, venturimeter is one connected to the apparatus gives accurate measurement of mass flow rate close to theoretical.

Hot wire anemometers can provide accurate local velocity of the fluid. By measuring the velocity at various radial points and integrating one would obtain the most accurate volumetric (or mass) flow rate in a pipe. https://www.sciencedirect.com/topics/engineering/hot-wire-anemometer

Thank you Srini Vasan for your answer.

Mass flow rate of a fluid can be measured by an instrument. The accuracy of the measurement and its dependency governs by several factors. If space is not an limitation, venturimeter is the best and if the space is confined, then orifice meter can be used but one has to multiply by a factor of around 0.62 to get actual.

To measure accurately the mass flow rate of fluid, venturimeter is the best instrument. This has a shape of converging and diverging section, where converging section is smaller in length compared to diverging section and gradual increase and this instrument is fitted with U- tube manometer. The coefficient of discharge for this instrument varies in between 0.96-0.99.

You can use "mass flow controller" of different material. This controller can measure accurately & has least error.

Thank you Mohammad Asif Kabir for your answer.

In order to measure mass flow rate of fluid, venturimeter is the most accurate one since the theoretical discharge calculated is almost the same as by measurement, thereby by mass flow rate can be determined.

Measurement of mass flow rate is made by connecting a U- tube manometer to the device as an accessory. In mechanical point of view this can be venturimeter or orifice meter. Out of which, venturimeter is the more accurate device for measurement.

Mass flow rate is calculated by continuity equation. For this, the head or pressure difference is measured by connecting U- tube manometer connected to a device whether it may be venturimeter or orifice meter. Out of which venturimeter is taken to be an accurate device.

For measuring mass flow rate of liquid flowing inside tube, venturimeter is the most accurate device. Since experimental measurement by venturimeter is 0.96-0.99 times theoretical measurement. Next comes, orifice meter which is 0.6- 0.62 times theoretical measurement.

As per my knowledge, for measuring mass flow rate of fluid, venturimeter and orifice meter are used. Out of these, venturimeter gives an accurate value since the value obtained is almost 98% of the theoretical value obtained.

If one wants to measure the flow rate of fluid, two instruments are there venturimeter and orifice meter, out if which venturimeter is the more accurate device. If these two instruments when connected, head is measured, discharge is calculated and finally mass flow rate is found.

Measurement of mass flow rate of fluid in fluid mechanics is by meters (venturimeter, orifice meter) connected at the entrance and at throat by recording pressure drop by manometer. Out of these, venturimeter is found to be the most accurate device for measurement of mass flow rate.