Hydraulics and Pneumatics: Unit I: Fluid Power Priniciples and Hydraulic Pumps

Reynold's Number

Fluid Power Priniciples and Hydraulic Pumps - Hydraulics and Pneumatics

Reynolds from his experiments found that the nature of flow in a closed pipe depends upon the following factors:

REYNOLD'S NUMBER

Reynolds from his experiments found that the nature of flow in a closed pipe depends upon the following factors:

(i) Diameter of the pipe (D),

(ii) Density of the liquid (p),

(iii) Viscosity of the liquid (μ), and

(iv) Velocity of flow (V).

By combining the above variables, Reynolds determined a non-dimensional quantity equal to ρ V D / μ which is known as Reynolds number (Re).


Laminar and turbulent flows are characterised on the basis of Reynolds number.

1. If Reynolds number (Re) < 2000, then the flow in pipes is laminar.

2. If Reynolds number (Re) > 4000, then the flow in pipes is turbulent.

3. If Reynolds number is between 2000 and 4000, then the flow in pipes is unpredictable.

Since turbulent flow results in greater losses, therefore hydraulic systems should be designed to operate in the laminar flow region.

The turbulent flow can be converted into laminar flow by either reducing the velocity of liquid or by increasing the pipe diameter.

Hydraulics and Pneumatics: Unit I: Fluid Power Priniciples and Hydraulic Pumps : Tag: : Fluid Power Priniciples and Hydraulic Pumps - Hydraulics and Pneumatics - Reynold's Number


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Hydraulics and Pneumatics

ME3492 4th semester Mechanical Dept | 2021 Regulation | 4th Semester Mechanical Dept 2021 Regulation