# Questions on Venturi Meter for Measuring Fluid Flow Rates

Question

A Venturi meter is a device used to measure fluid flow rates. It consists of a tapered constriction in a line with pressure taps leading to a differential manometer at points upstream of the constriction and at the point of maximum constriction. The manometer reading is directly related to the flow rate in the line.

a) Starting from the energy balance on an open system at steady state, derive Bernoulli’s equation:

ΔP⁄ρ + Δv2/2 + gΔz = 0

where âˆ† = value at point 2 – value at point 1, P is the pressure of the fluid, ρ is the fluid density, v is the average fluid velocity, g is gravitational acceleration, and z is average fluid height.  Bernoulli’s equation is an expression for the conservation of mechanical energy where the process is assumed to be frictionless with no shaft work. The following relationships may be helpful to you:

v = 1/ρ

ΔU - Q/m = F

where V is the specific volume of the fluid [volume/mass], U is the specific internal energy [energy/mass], Q is the heat flow rate [energy/time], m is the mass flowrate, and F is defined as the energy lost to friction in pipes.

b) Suppose the flow rate of an incompressible fluid is to be measured in a Venturi meter when A, the cross-sectional area at point 1, is four times that at point 2. Relate the velocities v11 and v at points 1 and 2, respectively.

c) Using your results from parts a) and b), relate the pressures in point 1 and point 2 (P2 and P, respectively).

d) Suppose this meter is used to measure the flowrate of a stream of water, using mercury as 2 the manometer fluid. A manometer reading of h = 38 cm is recorded. What is the volumetric flow rate of water if the pipe diameter at point 1 is 15 cm? If carbon tetrachloride were instead used as the manometer fluid, what would the manometer read?

Summary

The question belongs to Chemical Engineering and the question is about Venturi meter used for measuring fluid flow rates. If the flow rate of an incompressible fluid is to be measured in a Venturi meter, what would be the result. This and other questions have been answered with calculations in the solution.

Note: The answers are in handwritten format

### Comments

• Rasha

this is a very good website

• maani

I have 50 questions for the same test your page is showing only 28

• joeanne

hi can you please help or guide me to answer my assignments. thanks

• joeanne

hi can anyone help or guide me to my assignments. thanks

• Monik

• Cristina

This solution is perfect ...thanks

• Janete

Hello Allison,I love the 2nd image that you did! I also, had never heard of SumoPaint, is something that I will have to exolpre a bit! I understand completely the 52 (or so) youtube videos that you probably watched. Sometimes they have what you want, sometimes they don't! However, it is always satisfying when you are able to produce something that you have taught yourself. Great job!Debra 0 likes

• Sandeep

Perfect bank of solution.

• Oxana

great !

• Paul Brandon-Fritzius

thanks for the quick response. the solution looks good. :)

• tina Johnson

thnx for the answer. it was perfect. just the way i wanted it.

• Giuseppe

works fine.