Volume flow rate and mass flow rate

AI Thread Summary
The discussion revolves around calculating flow rates in a tapering pipe with diameters of 410mm and 260mm. The user initially miscalculated the flow rates by using diameters instead of areas, leading to incorrect velocity and mass flow rate results. The correct approach involves calculating the cross-sectional areas based on the diameters before applying the flow rate equations. After receiving feedback, the user acknowledges the mistake and expresses gratitude for the clarification. Accurate calculations are crucial for determining fluid dynamics in such systems.
MNWO
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Hello there, so I have answered my question from fluid systems but the answer doesn't look right ;/ and I have no idea what have I done wrong. Can you please check and correct where it's wrong ? ;) here is the question:
A pipe contains a gradually tapering section in which its diameter decreases from 410mm to 260mm. The pipe contains an incompressible fluid of density 1000kgm- 3 and runs full. If the flow velocity is 2ms in the smaller diameter, determine the velocity in the larger diameter, the volume flow rate and the mass flow rate.


My calculations:
A1=260mm=0.26m
V1=2ms
A2=410mm=0.41m
V2=?
Flow rate (Q)=A1 x V1 which is equal to A2 x V2
0.26 x 2=0.52 m/s 3 (metres per second cubed)
V2= Q/A2 = 0.52/0.41
V2=1.26 m/s 3
mass flow rate (M)= Density x Q = 1000x 0.52
M=520 kg/s

I would really aprreciate any help :)
 

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MNWO said:
Hello there, so I have answered my question from fluid systems but the answer doesn't look right ;/ and I have no idea what have I done wrong. Can you please check and correct where it's wrong ? ;) here is the question:
A pipe contains a gradually tapering section in which its diameter decreases from 410mm to 260mm. The pipe contains an incompressible fluid of density 1000kgm- 3 and runs full. If the flow velocity is 2ms in the smaller diameter, determine the velocity in the larger diameter, the volume flow rate and the mass flow rate.


My calculations:
A1=260mm=0.26m
V1=2ms
A2=410mm=0.41m
V2=?

Be careful here. You were given the diameters of the pipe, not the areas. How does the area of a pipe depend on its diameter?

Flow rate (Q)=A1 x V1 which is equal to A2 x V2
0.26 x 2=0.52 m/s 3 (metres per second cubed)
V2= Q/A2 = 0.52/0.41
V2=1.26 m/s 3
mass flow rate (M)= Density x Q = 1000x 0.52
M=520 kg/s

I would really aprreciate any help :)

See comment above.
 
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SteamKing said:
Be careful here. You were given the diameters of the pipe, not the areas. How does the area of a pipe depend on its diameter?
See comment above.[/QUOT
Ah okay, i know what's wrong now. Thank you for that
 

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