Electrowave- Frequency and Cavitation Values
Electrowave
|
|
|
|
|
|
|
|
|
10 |
330 |
0.15 |
(100) |
1.37 |
(100) |
10 |
3.5K |
|
20 |
165 |
0.019 |
(12.5) |
0.34 |
(25) |
20 |
27.8K |
|
30 |
110 |
0.006 |
(3.70) |
0.15 |
(11.1) |
30 |
94K |
|
40 |
80 |
0.0024 |
(1.56) |
1.086 |
(6.25) |
40 |
218.6K |
|
50 |
66 |
0.0012 |
(0.80) |
0.055 |
(4.0) |
50 |
435K |
|
60 |
55 |
0.0007 |
(0.46) |
0.038 |
(2.76) |
60 |
751K |
|
70 |
47 |
0.0004 |
(0.29) |
0.028 |
(2.03) |
70 |
1204K |
|
80 |
41 |
0.0003 |
(0.19) |
0.021 |
(1.56) |
80 |
1814K |
|
90 |
37 |
0.0002 |
(0.14) |
0.017 |
(1.26) |
90 |
2468K |
|
100 |
33 |
0.00015 |
(0.10) |
0.014 |
(1) |
100 |
3478K |
As can be seen from the above data, as the frequency increases, the number of bubbles (per second) increase proportionally while the size of each bubble decreases proportionally. The intensity (bubble volume) decreases by a factor of 8x for every doubling of the frequency, while the surface area of each bubble decreases by 4x. So although more bubbles (2x) may be present (per second) at twice the frequency, their total surface area (all bubbles combined) is decreased by half, while the amount of power needed to maintain equal bubble volume increases 4x, This should not be confused with the amount of power required for instantaneous intensity (cavitation deferential) which remains 8x.
The cycle of each bubble is inversely related to the frequency (20KHz = 1/20,000th second) while the actual number of bubbles are based on the volume of the liquid, its radiation pressure and the total power output (amplitude or watt density) of the transducer. In a theoretically infinite volume of liquid with an infinite amount of power, it would be possible to produce an infinite number of cavitating bobbles for each stroke of the transducer at any given frequency. This, of course would only work in theory since it would imply an infinitely long transducer stroke. In practice, however, with a limited volume of liquid increasing the amplitude to its maximum point (negating cavitational unloading) would eventually result in the formation of so many bubbles that the radiating surface would be pushing against more gas than liquid, at this point any further input of power would result in a decrease in both efficiency and cavitation. This is termed maximum watt density and varies from liquid to liquid depending on the radiation pressure and frequency, which is determined by temperature and sound propagation velocity. It must be understood that maximum watt density can never be realized due to the incredible pressures and temperatures involved, as well as cavitational unloading which causes (especially at high intensities) more bubbles to be produced at the radiating surface.
ELECTROWAVE ULTRASONICS CORPORATION