Environmental Engineering Reference
In-Depth Information
physically termed a bounded phenomenon, meaning that the sonoluminescence exists in
a bounded region of parameter space for the bubble, a coupled magnetic ield being one
such parameter.
Noted physicist Julian Schwinger's theory of sonoluminescence [28] is based on the
Casimir energy theory, which suggests that the light in sonoluminescence is generated by
the vacuum within the bubble in a process similar to Hawking radiation, or the radiation
generated at the event horizon of blackholes. According to this vacuum energy explana-
tion, since the quantum theory holds that vacuum contains virtual particles, the rapidly
moving interface between water and gas converts virtual photons into real photons. This
is a direct relationship to the Casimir effect, and sonoluminescence may be quantum vac-
uum radiation [29].
6.7 Applications with Vortex Cavitation
The Watreco Company in Malmö, Sweden, and their line of products branded under the
name Vortex VPT (see Figure 6.1), is one that has been successfully applying the principles
of cavitation to treat water in multiple ways.
The water enters tangentially at the “fat” end and lows into the trumpet-shaped vor-
tex chamber, generating a strong vortex inside the chamber. Normal tap water contains
a lot of nanosized bubbles, and these small bubbles come in huge quantities. These small
bubbles are associated with increased viscosity as they generate drag. The vortex genera-
tor generates a subpressure in the center of the vortex, as can be observed as vortices much
like small tornados or hurricanes. Because of the strong pressure gradient with almost a
perfect vacuum in the center, contaminants obey the Archimedes principle. As a result,
less dense contaminants in water, such as the dissolved oxygen or other gases, cause the
bubbles to migrate toward the lowest pressure, which happens to be in the center axis.
On the way, they expand and combine with other bubbles and they end up in the center
of the vortex where we can ind an elongated thin bubble of gas with very low pressures.
From time to time, a part of the elongated bubble is cut off and transported away by the
low, and the water is degassed, or more correctly, “debubbled.” In this way, we can achieve
some very desirable effects.
FIGURE 6.1
Cross section of the Watreco vortex generator.
