Fluid Flow Calculation for Gravity-Driven System: Velocity and Pipe Diameter

In summary, the question is about determining the velocity and pipe diameter for water to flow from one storage tank to another via gravity, with a difference in elevation of 15m and a total pipe length of 50m. The suggested solution of using Bernoulli's equation may not be accurate due to the viscosity of the fluid, so it is recommended to follow saunderson's post for a more precise calculation.
  • #1
birddog
2
0
Hello there,

Im trying to figure this assignment question and I have hit hurdle. Can someone please help with figuring out what the velocity and pipe diameter will be??

Question:
In a plant 20m3(cubic)/h of water at 20 degrees C is to flow via gravity from a storage tank to another one. the difference in elevation is 15m and total pipe length is 50m.

I thought it would be 9.81 m/s because of gravity but that seems too fast.
Can someone please help.

Thanks in advance!
 
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  • #2
i would give bernoulli's equation a try

[tex]p + \frac{1}{2} \rho v^2 + \rho g h = \rm{const} [/tex]​
remember:

[tex] \dot V = \frac{v}{A} [/tex]​
 
  • #3
Just to be technical on this.

Bernoulli's equation only works well if the viscosity of the fluid can be neglected.

Follow saunderson's post. I just wanted to throw the viscosity bit in.

Thanks
Matt
 
Last edited:

1. What is the relationship between velocity and pipe diameter?

The velocity of a fluid flowing through a pipe is inversely proportional to the pipe's diameter. This means that as the diameter of a pipe decreases, the velocity of the fluid increases and vice versa.

2. How does the velocity of a fluid affect the pressure in a pipe?

According to Bernoulli's principle, as the velocity of a fluid increases, the pressure decreases. This is because the kinetic energy of the fluid increases, causing a decrease in its potential energy, which is reflected as a decrease in pressure.

3. Can the velocity of a fluid in a pipe exceed the speed of sound?

No, the velocity of a fluid in a pipe cannot exceed the speed of sound. This is because the speed of sound is the maximum speed at which information can be transmitted within a fluid, and exceeding this speed would result in shock waves and potential damage to the pipe.

4. How does the viscosity of a fluid affect its velocity in a pipe?

The viscosity of a fluid has an indirect effect on its velocity in a pipe. A higher viscosity fluid will have a lower velocity due to the higher resistance to flow, while a lower viscosity fluid will have a higher velocity due to less resistance.

5. What is the critical velocity in a pipe?

The critical velocity is the point at which the velocity of a fluid in a pipe reaches the speed of sound. At this point, the fluid is considered to be in a state of choked flow, and any further increase in velocity will not result in an increase in mass flow rate.

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