Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion

In divergent section is acts as diffuser whrere pressure increases and velocity decreases.

In detail.

As the water enters venturi in the convergent cone where pressure drops and velocity increases (acts as a nozzle) at the throat velocity is very high where the pressure is below the atmospheric after the throat divergent cone is provided in order to regain the loss of pressure so velocity is decreases and pressure increases.

As in case nozzle meter, there is no divergent cone.

It is not the nozzle they are asking about, It is VENTURIMETER.

Velocity increases and pressure decreases both in convergent and divergent section in case of nozzle and fluid finally comes out with a huge velocity.

But in case of VENTURIMETER which is used to measure the flow in a pipeline, velocity increases and pressure decreases in convergent section and velocity decreases and pressure increases in divergent section.

As compare to convergent portion divergent area is decrease then velocity is increased. Because divergent angle is 3 to 5 and convergent angle 20.

Liquid flowing through the divergent portion of a venturimeter velocity decreases and for make the energy constant pressure of liquid increases.

Discharge remains the same trough out Q= AV.

As the area increases for the diverging section, obviously, velocity will decrease.

How could be velocity increase if area is increasing as q=av but what about pressure it should be increase or decrease.

Its wrong. Velocity of the liquid in divergent cone will increase and pressure will decrease.

As In divergent part area increasing so pressure decrease & velocity will increase.

Velocity will be decrease and pressure will be increase at the divergent portion.

Velocity decreases and pressure increases in divergent section of venturimeter.