Downscaling of sample entropy of nanofluids by carbon allotropes

ǂa ǂthermal lens study

Mohanachandran Nair Sindhu Swapna (Author), Vimal Raj (Author), S. Sreejyothi (Author), K. Satheesh Kumar (Author), Sankaranarayana Iyer Sankararaman (Author)

Abstract

The work reported in this paper is the first attempt to delineate the molecular or particle dynamics from the thermal lens signal of carbon allotropic nanofluids (CANs), employing time series and fractal analyses. The nanofluids of multi-walled carbon nanotubes and graphene are prepared in base fluid, coconut oil, at low volume fraction and are subjected to thermal lens study. We have studied the thermal diffusivity and refractive index variations of the medium by analyzing the thermal lens (TL) signal. By segmenting the TL signal, the complex dynamics involved during its evolution is investigated through the phase portrait, fractal dimension, Hurst exponent, and sample entropy using time series and fractal analyses. The study also explains how the increase of the photothermal energy turns a system into stochastic and anti-persistent. The sample entropy (S) and refractive index analyses of the TL signal by segmenting into five regions reveal the evolution of S with the increase of enthalpy. The lowering of S in CAN along with its thermal diffusivity (50%–57% below) as a result of heat-trapping suggests the technique of downscaling sample entropy of the base fluid using carbon allotropes and thereby opening a novel method of improving the efficiency of thermal systems.

Keywords

carbon allotropic nanofluids;time series;entropy;MWCNT;thermal lens signal;

Data

Language:	English
Year of publishing:	2020
Typology:	1.01 - Original Scientific Article
Organization:	UNG - University of Nova Gorica
UDC:	53
COBISS:	113296387
ISSN:	1054-1500
Views:	499
Downloads:	0
Average score:	0 (0 votes)
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Other data

URN:	URN:SI:UNG
Pages:	str. 073116-1-07311-9
Volume:	ǂVol. ǂ30
Issue:	ǂiss. ǂ7
Chronology:	2020
DOI:	10.1063/5.0009756
ID:	15786684