In this study, a coaxial rotating probe-type microwave
(MW) reactor
for nanoparticle synthesis was designed, and its performance was analyzed
using numerical modeling. The heating characteristics of the reactor
were systematically analyzed in terms of average temperature, maximum
temperature, temperature variance coefficient, and maximum temperature
difference. The results showed that the introduction of rotating probes
effectively eliminated the hot spots in the reactor, which could preclude
the nanoparticle synthesis process from being affected by the temperature
difference inside the reactor and greatly improve the MW heating efficiency.
The maximum temperature difference inside the reactor was reduced
by more than five times at a heating time of 60 s with the rotating
probes. Subsequently, the effects of the main factors, such as MW
input power, frequency, solution dielectric properties, probe configuration,
and probe rotational speed, were analyzed. The results showed that
the hot spot indicator Hs and the temperature variance COVT can be reduced by at least three times at the conditions of MW frequency f = 2.45 GHz with probe configurations of Ψ2
* = 0.08333 and
Ψ3
* =
0.29166 when selecting the probe rotational speed of Ω1 = 16,513. Reasonable regulation of the dielectric constant and dielectric
loss factor of the solution can make the solution’s response
to MW heating ideal. Increasing the probe rotational speed is very
effective at weakening the hot spot. In addition, comparison among
the designed reactor, a multimode cubic cavity reactor, and a stationary
coaxial probe reactor was conducted, showing that the designed reactor
exhibited much better performance in terms of Hs and COVT.