Technical Info

Around 1990, it was believed that “cavities generated by ultrasound are spherical cavities. It was said that the cavities disappear under the pressure of the dense and rarefied waves of ultrasound, and at that time, the pressure waves of the surrounding liquid concentrate towards the center of the spherical cavity, causing high pressure and high temperatures to be generated.” At the time, the theory of cavity collapse was very easy to understand, and the mainstream view was that pressure would be concentrated in an infinitesimal part of the center of the spherical cavity. As a result, there was great anticipation for the physical phenomena of ultrasonic cavities, and people dreamed of physical phenomena caused by astronomical pressure concentration and high temperatures, with the central core at the time of cavity collapse being reduced to zero. An extreme example of this is cold fusion.
When I heard the news of the successful cold fusion experiment using ultrasound, I immediately obtained information on the experimental method and was surprised when I saw it. This was because I immediately realized that the researcher was an amateur when it came to ultrasound. It was a terrible experiment that did not reach the level of obtaining experimental data, using an experimental machine that could not be reproduced.
Between 1990 and 1993, I presented a new ultrasonic cleaning technology at an international conference on the protection of the stratosphere ozone layer held in Washington. It is an ultrasonic cleaning method that uses water to achieve cleaning performance that is superior to that of CFC-113, without using CFC-113 (CFC-113). Depending on the amount of dissolved air in the water (represented by the concentration of dissolved oxygen), the shape of the cavities generated by ultrasonic waves is divided into two main types. When the amount of dissolved air is large, the cavities are a collection of cavities of around 0.1mm in diameter (called micro-cavities), and the shape is very similar to various types of gas nebula, so I called them gas nebula-type cavities. This is because the energy generated and dissipated by the micro-cavities is not only small individually, but also distributed unevenly, so it is not possible to use the energy efficiently as a collective.
I explained that this gas nebula-type cavity should be used for rough cleaning of oil and swarf. It is insufficient as a substitute for CFC-113.
If the amount of dissolved air in water is reduced to 3mg/ℓ or less in terms of dissolved oxygen, the shape of the cavity becomes spherical. The size of the microcavities inside generally becomes 1mm or more in diameter, and they gather together to form a spherical cavity.
Because of its shape, I have named this cavity the “spherical nebula cavity”. The size of this spherical nebula cavity
currently ranges from 3mm to 10mm, depending on the application. In this cavity, each of the micro-cavities that make up the cavity is spherical and repeats the process of generation and annihilation in synchronization. At an international conference on the protection of the stratosphere ozone layer, I announced that water could be used for precision cleaning instead of CFC-113. The conditions for this could be achieved by using this spherical nebula-type cavity. As a result, I received the Stratospheric Ozone Protection Award from the US Environmental Protection Agency.

35 years have passed since then.
The Spherical Nebula Cavity has been used for a wide range of applications, including high-power ultrasonic precision cleaning, ultrasonic deburring, ultrasonic polishing, ultrasonic etching, ultrasonic 3D internal fine powder removal for metals, ultrasonic biofuel production, ultrasonic nanocellulose production, ultrasonic organic polymer low-molecular-weight production, and metal nanoparticle production.
However, it is clear that cold fusion is impossible due to the shape of the spherical nebula-type cavity, but on the other hand, it is still not possible to grasp what kind of energy fluctuations are occurring inside the spherical nebula-type cavity.

Where are the limits?

What kinds of uses are possible from now on? How far are the possibilities?

In the case of 20 kHz ultrasound, the behavior of the cavity is clear.
The generation and disappearance of the cavity is captured by a high-speed camera with a resolution of 210 millionths of a second.
The cavity, which has a maximum diameter of 10 mm, is made up of micro-cavities with diameters of 1 to 2 mm.
At 20 kHz, the cavity is generated in about 1/40,000 of a second, reaches its maximum shape, and then disappears in the next 1/40,000 of a second.
Rather than the size of the cavity changing, the position of each micro-cavity from the central core of the cavity does not change,
and the micro-cavities that make up the cavity are repeatedly generated and disappear.
The speed of generation and disappearance at that time is faster for disappearance than for generation.
(Therefore, it is not correct to say that they are generated in 1/40,000 of a second and disappear in 1/40,000 of a second.)
The difference in speed is affected by atmospheric pressure.
Our company controls the speed at which they disappear by pressurizing the air. This is called implosion technology.
The cavities themselves move at about 100 meters per second.

What kind of force is working inside the cavities at this time?

What kind of shock force is generated inside the cavity when the microcavity is created and disappears?
What kind of pressure change can we obtain by controlling the water pressure?

Can we simulate the possibilities using scientific and technological calculations in parallel with the experiments?

I would like to ask for your help.
by shibano