FLuid Flow through a Divergent Section

[astronautnandu]

Hi,
Can Someone Elaborate the fluid(water) Characteristics Such as Velocity n pressure When it passes through a divergent Part. Actually The Fluid is pumped Out from A 0.5HP Centrifugal Pump and then made to pass through a Divergent Part.

 

[Bobbywhy]

astronautnandu, Welcome to Physics Forums!

For fluid flow through a divergent part please see question 3.4 in:
http://www.efm.leeds.ac.uk/CIVE/CIVE1400/Examples/eg3_ans.htm

Also, see page 12 of 25 (p. 123 of book), section 7.4.2: Loss with gradual change of area.
Divergent pipe or diffuser, equations (7.28) through (7.32) and Fig. 7.13
http://www.scribd.com/doc/9712922/Introduction-to-Fluid-Mechanics-Ch07

If these references don’t satisfactorily answer your question, please return here to Physics Forums and post your doubt or question. Please be as clear and exact as possible when describing your scenario.

Cheers,
Bobbywhy

 

[sanka]

Due to conservation of mass (continuity), the mass flow rate before the divergent section = the mass flow rate after the divergent section. The mass flow rate at any section=ρUA. So if the flow area increases (as in a diverging section), the velocity has to decrease to satisfy continuity (for a fluid of constant density such as water).

If the velocity of a fluid decreases, the pressure associated with the kinetic energy of the fluid continuum, known as the dynamic pressure, decreases. Thus in accordance with Bernoulli, the static pressure increases.

It is the opposite for a converging section.

 

[Engineer_Phil]

Look up Bernoulli's Law.

Depending on your situation, can could assume inviscid fluid to simplify things.

You also have to be careful that the divergence of the section isn't too extreme. If it is the assumption that the velocity is uniform throughout a particular cross section will not be valid.

 

[alphy]

Sure, I would be happy to elaborate on the characteristics of water as it passes through a divergent section. Firstly, it is important to understand that fluid flow through a divergent section follows the principle of conservation of mass and energy.

As water is pumped out from a 0.5HP centrifugal pump, it enters the divergent section with a certain velocity and pressure. The divergent section is designed to gradually increase the cross-sectional area of the flow path, causing the water to expand and slow down as it moves through the section.

As the velocity of the water decreases, the pressure increases due to the conservation of energy. This is known as the Bernoulli's principle, which states that as the velocity of a fluid decreases, its pressure increases.

In addition to this, the divergent section also causes a decrease in the kinetic energy of the water. This is because the energy of the water is used to overcome the increase in pressure and the frictional forces within the divergent section.

Overall, the characteristics of the water passing through a divergent section can be summarized as a decrease in velocity, an increase in pressure, and a decrease in kinetic energy. These changes in the fluid's characteristics are important in various engineering applications, such as in hydraulic systems and aerodynamics. I hope this clarifies your question.