Imperial College London

Dr Antonis Sergis

Faculty of EngineeringDepartment of Mechanical Engineering

Lecturer
 
 
 
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Contact

 

a.sergis09 Website

 
 
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Assistant

 

Ms Eniko Jarecsni +44 (0)20 7594 7029

 
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Location

 

619City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@inbook{Iqbal:2022:10.1039/9781839166457-00041,
author = {Iqbal, M and Sergis, A and Hardalupas, Y},
booktitle = {Fundamentals and Transport Properties of Nanofluids},
doi = {10.1039/9781839166457-00041},
editor = {Murshed},
pages = {41--70},
publisher = {Royal Society of Chemistry},
title = {Stability of nanofluids},
url = {http://dx.doi.org/10.1039/9781839166457-00041},
year = {2022}
}

RIS format (EndNote, RefMan)

TY  - CHAP
AB - Stability is key to sustaining the colloidal properties of nanofluids and by extension the beneficial thermophysical properties they exhibit for practical applications. Nanofluid suspensions are typically prepared through ultrasonic dispersion of nanoparticles, either using low-power ultrasonic baths or high-power ultrasonic probes. It has been observed that high-power probes, although achieving nanoparticle size reduction in a short time, can also cause considerable aggregation of particles and hence reduction in colloidal stability with excessive application. This effect is not observed in low-power ultrasonic dispersion applications. This discrepancy and its sources are explored and explained in the current chapter, through consideration of particle breakup mechanisms (fragmentation versus erosion) and the fusion of particles due to high-velocity interparticle collisions. Stability is known to be linked to solution pH; for example a pH value far from the isoelectric point yields a surface charge in the dispersed phase, which enhances stability through coulombic repulsion. Ultrasonication has been observed to affect the pH of nanofluid solutions. High-power devices are unable to affect pH change in dilute alumina–water nanofluids ( < 0.01 vol%), whereas low-power devices can. This is hypothesised to be due to the dominant breakup mechanism, i.e., erosion in low-power baths versus fragmentation in high-power probes. Hence, to improve nanofluid stability, it is recommended to use low-power sonication where possible, and source nanoparticles in aqueous form. If a high-power ultrasonic probe must be used, the duration and amplitude should be reduced to avoid the induction of significant stability reduction.
AU - Iqbal,M
AU - Sergis,A
AU - Hardalupas,Y
DO - 10.1039/9781839166457-00041
EP - 70
PB - Royal Society of Chemistry
PY - 2022///
SN - 978-1-83916-646-4
SP - 41
TI - Stability of nanofluids
T1 - Fundamentals and Transport Properties of Nanofluids
UR - http://dx.doi.org/10.1039/9781839166457-00041
UR - https://books.rsc.org/books/edited-volume/2039/chapter/4661043/Stability-of-Nanofluids
UR - http://hdl.handle.net/10044/1/99911
ER -