# Determine the pressure in the pipe

• zetshield21
In summary, the conversation discusses a pipeline with a water level difference of 5m, a total length of 700m, and a section AB of 300m. Point B is 3m above the free surface of reservoir A, and the diameter of the pipe is 1m with a friction factor of 0.02. The conversation asks to determine the flow rate in the pipe and the pressure at point B. The conversation uses the formula H=f*l*v^2/(d*2g) for the flow rate and Bernoulli's equation from point A to B for the pressure. The attempt at a solution uses the equation -Pa/pg+Z1=Pb/pg+Z2+Hl, assuming Pa
zetshield21

## Homework Statement

a pipeline which connects two reservoirs which has a water level difference of 5m. the total length of the pipe is 700m and the length of section AB is 300m. Point B is at a level of 3m above the free surface of the water in reservoir A. If the diameter of the pipe is 1m and the friction factor is 0.02,Determine
i) the flow rate in the pipe
ii)the pressure at point B

## Homework Equations

i have use formula H=f*l*v^2/(d*2g) for the flow rate
and i use the bernoulli's eguation from point A to B

## The Attempt at a Solution

for the solution II)
from point A to B
-Pa/pg+Z1=Pb/pg+Z2+Hl
where i assumed that Pa=101.3kpa, Z1=0,Z2=3and Hl=f*l*v^2/(2*d*g)
and Pressure at B,Pb that i get is 63.86kpaDid my answer is correct for question 2

Last edited:
EDITed try:
I don't know how to handle the friction loss, but ignoring that, going to Bernoulli:

at A surface, constant = pat/ρ;
at A outlet, = v2/2 -gdA + pA/ρ where dA = depth of A outlet below surface & not given;
at B, = v2/2 + gh1 + pB/ρ where h1 = 3m
at C inlet, = v2/2 - gh2 - gdB + pB/ρ where h2 = 5m and dB = depth of C inlet below its surface & not given;

but pB = pat + ρgdB so the C inlet expression simplifies to
v2/2 - gh2 + pat/ρ.

From the last,
v2 = 2gh2 so v ~ 9.9 m/s and from the B expression,
pB = 21.6 kPa

Maybe you can figure out from the above (1) if it sounds right, and (2) how to factor in the friction loss. That loss is pretty small so I would think our answers should not differ by that much.

Last edited:
zetshield21 said:

## Homework Statement

a pipeline which connects two reservoirs which has a water level difference of 5m. the total length of the pipe is 700m and the length of section AB is 300m. Point B is at a level of 3m above the free surface of the water in reservoir A. If the diameter of the pipe is 1m and the friction factor is 0.02,Determine
i) the flow rate in the pipe
ii)the pressure at point B

## Homework Equations

i have use formula H=f*l*v^2/(d*2g) for the flow rate
and i use the bernoulli's eguation from point A to B

## The Attempt at a Solution

for the solution II)
from point A to B
-Pa/pg+Z1=Pb/pg+Z2+Hl
where i assumed that Pa=101.3kpa, Z1=0,Z2=3and Hl=f*l*v^2/(2*d*g)
and Pressure at B,Pb that i get is 63.86kpa

Did my answer is correct for question 2

If the inlet and outlet of the pipe were at the same elevation, what would be the relationship between the pressure drop and flow rate, taking into account the friction loss? Start out by writing the general equation between pressure drop and flow rate in terms of the density, mean velocity = Q/A, drag coefficient, length of pipe, and diameter of pipe. Then plug in numbers for water.

## 1. What is the formula for determining pressure in a pipe?

The formula for determining pressure in a pipe is P = F/A, where P is pressure, F is force, and A is the cross-sectional area of the pipe.

## 2. How do you measure the pressure in a pipe?

The pressure in a pipe can be measured using a pressure gauge, which typically works by converting the force exerted by the fluid into a reading on a dial or digital display.

## 3. What are the units of measurement for pressure in a pipe?

The SI unit for pressure is Pascal (Pa), but other commonly used units include pounds per square inch (psi), kilopascal (kPa), and bar.

## 4. How does the diameter of the pipe affect the pressure inside?

The pressure inside a pipe is inversely proportional to the diameter of the pipe. This means that as the diameter increases, the pressure decreases, and vice versa.

## 5. What factors can cause a change in pressure inside a pipe?

Several factors can cause a change in pressure inside a pipe, including changes in fluid flow rate, changes in pipe diameter, and the presence of obstructions or bends in the pipe.

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