- #1

Femme_physics

Gold Member

- 2,548

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Again-- I'm not entirely sure if this goes to physics or engineering, but the word thing that comes in mind when I hear Bernoulli equation is PHYSICS, so I decided to post it here...

So I have this hydraulic system

http://img689.imageshack.us/img689/3596/clipboard01rvt.jpg [Broken]

With the figures

H1 = Height of suctioning = 3m

H2 = Height of delivery = 25m

D1 = diameter of the suctioning pipe = 150mm

D2 = diameter of the delivery pipe = 100mm

Q = 0.02 [m^3/s]

y1 = pressure lost at the suctioning line

y2 = pressure lost at the delivery line

Energy conversation efficency of the pump = 75%

Find the pressure at the pump's entrance (p1).

In the solution

So I build the equation:

http://img196.imageshack.us/img196/2145/ber1j.jpg [Broken]

http://img21.imageshack.us/img21/9740/ber2h.jpg [Broken]

HOWEVER, the result in my manual is different. It's p1 = -0.05064x10^5 [Pa]

I don't get how could we have gotten such hugely different results!

## Homework Statement

So I have this hydraulic system

http://img689.imageshack.us/img689/3596/clipboard01rvt.jpg [Broken]

With the figures

H1 = Height of suctioning = 3m

H2 = Height of delivery = 25m

D1 = diameter of the suctioning pipe = 150mm

D2 = diameter of the delivery pipe = 100mm

Q = 0.02 [m^3/s]

y1 = pressure lost at the suctioning line

y2 = pressure lost at the delivery line

Energy conversation efficency of the pump = 75%

Find the pressure at the pump's entrance (p1).

## Homework Equations

In the solution

## The Attempt at a Solution

So I build the equation:

http://img196.imageshack.us/img196/2145/ber1j.jpg [Broken]

http://img21.imageshack.us/img21/9740/ber2h.jpg [Broken]

HOWEVER, the result in my manual is different. It's p1 = -0.05064x10^5 [Pa]

I don't get how could we have gotten such hugely different results!

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