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A venturi meter is a device for measuring the speed of a fluid within a pipe. The drawing shows a gas flowing at a speed v2 through a horizontal section of pipe whose cross-sectional area A2 = 0.0800 m2. The gas has a density of rho = 1.20 kg/m3. The Venturi meter has a cross-sectional area of A1 = 0.0300 m2 and has been substituted for a section of the larger pipe. The pressure difference between the two sections is P2 - P1 = 140 Pa. Find the speed v2 of the gas in the larger original pipe. Find the volume flow rate Q of the gas.

Respuesta :

Answer:

[tex]V_2=6.17\ m/s[/tex]

[tex]Q=0.49\ m^3/s[/tex]

Explanation:

Given that

[tex]A_1=0.03m^2[/tex]

[tex]A_2=0.08m^2[/tex]

We know that from continuity equation

[tex]Q=A_1V_1=A_2V_2[/tex]

So

[tex]A_1V_1=A_2V_2[/tex]

[tex]0.3V_1=0.08V_2[/tex]

[tex]V_1=2.66V_2[/tex]

Now from energy equation

[tex]P_1+\dfrac{1}{2}\rho V_1^2=P_2+\dfrac{1}{2}\rho V_2^2[/tex]

[tex]P_2-P_1=\dfrac{1}{2}\rho V_1^2-\dfrac{1}{2}\rho V_2^2[/tex]

[tex]140=\dfrac{1}{2}\times 1.2\times 7.11\times V_2^2-\dfrac{1}{2}\times 1.2\times V_2^2[/tex]

[tex]V_2=6.17\ m/s[/tex]

[tex]Q=A_2V_2[/tex]

Q=6.17 x 0.08

[tex]Q=0.49\ m^3/s[/tex]