What is pressure drop when it comes to piping?
Pressure drop refers to the loss of pressure within the piping system used for the movement of fluids.

More precisely, pressure drop is a phenomenon that comes from studies on fluid mechanics and is due to friction caused by the viscosity of the fluid. This means that the higher the viscosity of a fluid, the greater the pressure drop.


There are two types of pressure drops:

  1. Singular pressure drops: These are variations in velocity caused by special parts to change the direction of a fluid. For example, a 90° elbow in the pipe
  2. Linear pressure losses: They consist of the loss of fluid velocity caused by the length of the pipes, the roughness of the pipe and the viscosity of the fluid.
    1. Note that the two types of pressure drops can be in pairs. This means that a part used to change the direction of a fluid, if it is long enough, can also decrease the internal pressure by friction.

What Is the Purpose of Calculating the Pressure Drop

In the water treatment industry, taking pressure drops into account helps in several ways. During the manufacturing of systems, it helps us to choose the type of piping and its size.

For diagnostics, it helps us identify the source of problems related to pressure fluctuations.


How is it calculated?


In general, the regular pressure drop is calculated using Darcy's law.


ΔH = Λ ( L/Dh) (V2 /2g)

  • ΔH : Denotes the pressure drop;
  • Λ: Denotes the coefficient of the pressure drop (Reynolds number) ;
  • L: Represents the length of the pipe in metres;
  • Dh: Represents the hydraulic diameter;
  • V : Represents the average velocity of the fluid in metre per second ;
  • g: Represents the gravitational constant in metres per second squared.

in FAQ
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