*69. ssm A Venturi meter is a device that is used for measuring the speed of a fluid within a pipe. The drawing shows a gas flowing at speed u2 through a horizontal section of pipe whose cross-sectional area is A2 = 0.0700 m2. The gas has a density of ρ = 1.30 kg/m3. The Venturi meter has a cross-sectional area of A1 = 0.0500 m2 and has been substituted for a section of the larger pipe. The pressure difference between the two sections is P2 - P1 = 120 Pa. Find (a) the speed u2 of the gas in the larger, original pipe and (b) the volume flow rate Q of the gas.

 

w0585

Bernoulli equation gives us

 

Make the assumption that

Bernoulli reduces to

Solve for difference in pressure

 

Equation of Continuity gives

 

Assume an incompressible gas and 

 

And solving for v1

 

 

Now Solve for v2

 

 

 

 

 

 

 

 

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This page last updated on January 11, 2020