Electrowave

Comparison of Ultrasonic Cavitation Intensity in Various Liquids

Liquid

Formula

Boil Point (°C)

Maximum Cavitation Intensity for a Half-Wavelength Liquid Column (46 & 22 KHz) %

Temperature at which Cavitation reaches Maximum Intensity (°C)

Temperature Range over which Cavitation Intensity reaches from 70% - 100% of Maximum (°C)

Water

H2O

100

100

35

20 - 50

STYRENE

C6H5C2H3

146

74

37

24 - 53

TOLUENE

C6H5CH3

111

71

29

10 - 40

TETRALIN

C1OHI2

207

70

55

30 - 105

CYCLOHEXANONE

C6HIOO

155

70

36

0 - 45

XYLENE

C6H4(CH3)2

137

64

26

8 - 48

ETHYLENE GLYCOL

C2H4(OH)2

197

61

93

75 - 120

CYCLOPENTANOL

C5H9OH

141

59

49

38 - 70

Thichloroethylene

C2HC13

87

58

20

0 - 23

GLYCERINE

C3H5(OH)3

290

57

85

75 - 105

n-AMYLACETATE

CH3COOC5H11

149

57

18

2 - 32

Tetrachloroethylene

C2C14

121

56

42

33 - 63

n-BUTYLACETATE

CH3COOC4H9

126

56

21

-2 - 27

PYRROLE

C4H5N

130

55

40

25 - 75

METHANOL

CH3OH

65

52

19

4 - 23

CHLOROFORM

CHC13

61

50

-3

-11 - 15

n-AMYLALCOHOL

CSH11OH

137

47

23

-32 - 46

ETHANOL

C2H5OH

78

46

21

15 - 27

ETHYLACETATE

CH3COOC2H5

77

45

9

-5 - 16

ACETONE

(CH3)2C0

56

44

-36

-50 - -20

n-BUTYLALCOHOL

C4H9OH

118

43

32

10 - 45

BENZENE

C6H6

80

43

19

10 - 32

n-PROPANOL

C3H7OH

97

42

27

8 - 44

1,1,1-Trichloroethane

C2H3C13

74

41

18

-7 - 20

Methylene Chloride

CH2C12

40

38

-40

-60 - -25

METHYLACETATE

CH3COOCH3

57

38

-32

-40 - -10

i-PROPANOL

(CH3)2CHOH

82

38

16

0 - 30

FORMIC ACID(85%)

HCOOH

101

37

30

25 - 42

TRl-n-BUTYLAMlNE

(C4H9)3N

214

37

31

15 - 38

Carbon Tetrachloride

CC14

77

35

8

0 - 22

CYCLOHEXANOL

C6H11OH

160

23

37

35 - 40

PROPIONIC ACID

C2H5COOH

141

22

32

12 - 45

TRIETHYLAMINE

(C2H5)3N

89

21

1

-12 - 14

FREON 113

C2C13F3

48

15

-20

-30 - -5

FREON 11482

C2Br2F4

47

6

8

-5 - 18

ACETIC ACID

CH3COOH

118

6

48

20 - 60

It should be emphasized that the absolute values of cavitation intensity at 22 KHz & 46 KHz are different, but after setting the water cavitation in each case to 100, the other liquids have the same relative values. Thus it can be supposed that the maximum cavitation intensity value for half-wavelength heights (h = nc/2f) is a characteristic value for a given liquid and does not depend on frequency.

A short comment also needs to be made on the fact that the maximum cavitation intensity of water occurs at 35 ‘C, while it is well known that ultrasonic cleaning in aqueous (water) solutions can be performed with good effect at temperatures around 50C - 60C. It is important to note that the agents involved in ultrasonic cleaning arc not only cavitation, but also liquid streaming due to radiation pressure of the ultrasound, and chemical activity from substances dissolved in the water such as acids, alkalis or detergents. The cleaning intensity of these agents increase with temperature, and the total activity may produce a stronger cleaning effect at 60’C than at 35C.

A similar explanation can be applied to the Freons, which according to the above results support only slight cavitation. Their cleaning power with ultrasound is caused by especially high radiation pressure; this depends inversely on the sound propagation velocity, which in Freons is very low. However, when vacuum degassed, solvents such as Freon will cavitate with an intensity similar to that of water (while held in vacuum), although within seconds alter exposure to air the solvent reabsorbs the gas, due to an extremely high gas absorption coefficient, reducing its cavitational intensity by over 6x. Thus, relative cavitational intensities in the above liquids are not primarily related to frequency, density, viscosity, surface tension, vapor pressure, atoms, ions or other colligative properties, but depend almost entirely on the temperature and the amount of dissolved gas in the solution.