![]() ![]() To simulate the beating oscillations, this paper proposes a flame model that incorporates the flame dynamics at the amplitude modulation time scale (∼s) and the acoustic time scale (∼ms). The different characteristics of the beating oscillations near the upper and lower equivalence ratio limits are distinguished and explained by the coupling between the low frequency flame pulsations and the thermoacoustic instability. It is also found that low frequency flame pulsations arise with the amplitude modulations. The beating oscillations exhibit approximately 1 Hz or even lower frequency amplitude modulations for the acoustic pressure and the heat release rate. In addition to regular limit cycle oscillations, the thermoacoustic system also presents self-sustained periodic amplitude modulations, or beating oscillations, near the flame equivalence ratio limits of thermoacoustic instability. Thermoacoustic oscillations occur in a Rijke burner with a porous plug stabilized premixed flame. At the end of evolution, when the drying microdroplet transforms into a (non-rigid) microaggregate, the Brownian motion of the dispersed nanoparticles was masked by the rotational Brownian motion of the microaggregate as a whole. At the initial stage of the evaporation, apart from the optical morphology resonances of the droplet (dielectric sphere), it was possible to identify the characteristic times corresponding to the Brownian motion of the dispersed nanoparticles. It was found that the temporal variation of the ACF generally reflects the evolution of the microdroplet of dispersion. ![]() Exponentially decaying autocorrelation functions (ACFs) were obtained for the light scattered by evaporating microdroplets as well as for microaggregates of nanoparticles formed at the end of the evaporation process. The evaporating microdroplets were levitating in an electrodynamic quadrupole trap. We applied the dynamic light scattering (DLS) technique for studying single microdroplets of dispersions of SiO 2 and TiO 2 nanoparticles. ![]()
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