New Energy Technologies Magazine nr 3 2005.pdf - Index of

This possibility was controlled by using a
swirler as a passive mechanoactivator and
forwarding a cold water under strong pressure
at its inlet [58].
Due to the mechanoactivation, a water stream in
the swirler was characterized by a strong
maldistribution of local speeds and, accordingly,
by high gradients of mechanical tensions in the
liquid. Regions with negative pressures appeared
in the stream and conditions were formed for
tearing of the liquid's continuity and
development of cavitation processes. These
processes were accompanied by a clear sign of
cavitation – a sonoluminescent glow of the liquid
[59, 60] while a cavitating hot water, which was
in a condition close to a dispersion one, was
coming to the exit of the swirler.
While an initial water temperature had been T 1
= 20C at the swirler’s inlet, a water temperature
after a mechanical treatment increased up to T 2
= 55C. While the initial water temperature had
been T 1
= 40C, the water temperature after the
mechanical treatment increased up to T 2
= 85C.
While the initial water temperature had been T 1
= 66.5C, a boiling water came to the outlet of the
swirler.
A comparative appraisal of a quantity of
heat, which is equivalent to a
mechanoactivation work, and a quantity of
heat, which is necessary for water heating in
the given temperature intervals, allows
making a conclusion that an additional heat
generation happens during the
mechanoactivation process.
During the mechanical treatment causing an
intensive cavitation, a part of the water turns to
ordered, colloid-like, close to liquid-crystal, state
B 2
, and transition B 1
B 2
is accompanied by the
heat generation.
Such a transition can be determined as a “phase
transition in in the wide sense” [61], [62], which
results in excessive heat Q exc
generation:
B 1
B 2
+ Q exc
(1)
It is found out in work [58], that the partially
odered water state is unstable and accompanied
by a reverse transfer from metastable state B 2
in
state B 1
. Reverse transfer B 2
B 1
is endothermic
and can happen both with a relatively continuous
and an uneven absorption of heat:
B 2
B 1
– Q exc
(2)
Uneven phase change B 2
B 1
is accompanied by
an abrupt water cooling: for example, the water
temperature can lower from T 2
= 75C in
dispersion phase B 2
to T 1
= (45 – 55)C in B 1
phase.
Relaxation time τ r
during the reverse transition,
in dependence on stability of the environment and
water cleanness, can be a few or some dozen
minutes: τ r
= (3 – 30) min.
Thus, the mechanical water treatment
accompanied by an intensive cavitation [55, 58]
can lead to the generation and absorption of heat.
It is important to note that, in the event that hot
water temperature T 2
in dispersion state B 2
is
decreased, for example, by a heat exhange with
the environment, water temperature T 1
in
dispersion phase B 1
after the reverse transition
can be lower than the initial one.
This allows suggesting with sufficient certainty
that the effect of VLH is based on this. Various
manifestations of the above described heat
effects have been observed earlier. In front of a
buidling of the Estonian Academy of Sciencies
in Tartu, a fountain with stream-swirlers is
located. The swirlers form strong vertical
streams of a cavitating water hazed by a mist of
small waterdrops. In spite of the fact that a
water with an initial temperature of about 20C is
led to the swirlers, a temperature of a metastable
dispersion phase, which looks like small drops
hanging in the air near the cavitating streams, is
about 40C, and a final temperature of a liquid state,
which is a condensate in the fountain’s pool, does
not exceed 15C.
It is also know that water temperature can
increase during the phase change, if the partially
ordered liquid’s state is formed not by a surface of
a part “liquid - gas” but by a surface of a part “liquid
– soild”.
A heat produced during water moistening of
hydrophilic surfaces is ususally called a heat of
moistening. No matter which nature of this effect
34 New Energy Technologies #3(22) 2005