Cavitation in Pipe | Online Calculator

Fluid Dynamic Calculators







Cavitation in Pipeline

In the area of some local losses, the fluid flow rate increases sharply, the static pressure drops and, if it falls below the saturated vapor pressure, local boiling occurs at low temperatures. This phenomenon is called cavitation and accompanied by strong noise, vibration and water hammer. If cavitation occurs, local energy losses increase sharply.

In this calculation, the critical flow rate wcr is determined, which ensures the cavitation-free operation of the equipment. Finding the critical flow rate depending on fluid pressure P1, saturated steam pressure P2 and fluid density ρ is reduced to solving the following equation:

wcr = [2(P1 - P2) / ρ*σ] 1/2

σ - critical cavitation number.

INITIAL DATA

P1 - Fluid pressure before hydraulic resistance;


P2 - Saturated steam pressure;


ρ - Fluid density;


σ - Critical cavitation number. In most cases it can take values from 0.4 to 0.8 depending on type of hydraulic resistance.

RESULTS DATA

wcr - Critical velocity for cavitation.

Fluid pressure (P1)

Saturated steam pressure (P2)

Fluid density (ρ)

Cavitation number (σ)

Velocity (wcr)

BASIC FORMULAS

Critical velocity:

wcr = [2(P1 - P2) / ρ*σ]1/2

INITIAL DATA

P1 - Fluid pressure before hydraulic resistance;


P2 - Saturated steam pressure;


ρ - Fluid density;


σ - Critical cavitation number. In most cases it can take values from 0.4 to 0.8 depending on type of hydraulic resistance.

RESULTS DATA

wcr - Critical velocity for cavitation.

FLUID PROPERTIES

Fluid

Dynamic viscosity

Pa*s

(lb*s/ft2)

Density

Kg/m3

(lb/ft3)

Water

0.001

(0.0000208)

1005

(62.8)

Freon-11

0.00048

(0.00001)

1494

(93.4)

Freon-12

0.00028

(0.00000586)

1330

(83.1)

Freon-22

0.00025

(0.00000522)

1202

(75.1)

Freon-113

0.00074

(0.0000155)

1573

(98.3)

Kerosene

0.00256

(0.0000535)

804

(50.25)

Benzene

0.00069

(0.0000144)

879

(54.9)

Glycerol

1.393

(0.029)

1261

(78.8)

Ethanol

0.00122

(0.0000255)

789

(49.3)

Mercury

0.00159

(0.0000332)

13545

(846)

Linseed oil

0.044

(0.000919)

924

(57.75)

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