Effects of pH on heat transfer nanofluids containing ZrO2 and TiO2 nanoparticles

2011 ◽  
Vol 109 (2) ◽  
pp. 024305 ◽  
Author(s):  
Carine Tchamakam Wamkam ◽  
Michael Kwabena Opoku ◽  
Haiping Hong ◽  
Pauline Smith
Author(s):  
Deepak Khurana ◽  
Sudhakar Subudhi

Abstract The present paper deals with the forced convection of Al2O3/water and TiO2/water nanofluids with the variation of pH and addition of surfactant in nanofluids. The aim of this study is to investigate the effect of suspension stability on the heat transfer and pressure drop characteristics of nanofluids. The present experimental set up is same as used by our earlier paper [1]. The suspension stability of nanofluids is improved by varying pH of nanofluids. The pH in this study is varied from 3.5±0.2 to 12.5±0.2. Addition of surfactants is employed to improve the suspension stability of nanofluids. The SDS (sodium dodecyl sulfate) surfactant of 0.05 wt % is used to increase the stability of nanofluids in the present study. It is observed that by increasing the suspension stability with the variation of pH and addition of surfactant, the heat transfer characteristics have improved appreciably. The maximum enhancement in heat transfer is obtained with TiO2/water nanofluids at a particle concentration of 0.1 vol % and a pH of 3.5±0.2.


2019 ◽  
Vol 26 (8) ◽  
pp. 2129-2135
Author(s):  
Xiang Yin ◽  
Guang-xiao Kou ◽  
Ai-xiang Xu ◽  
Tao Fu ◽  
Jie Zhu

Author(s):  
B.A. Bhanvase ◽  
M.R. Sarode ◽  
L.A. Putterwar ◽  
Abdullah K.A. ◽  
M.P. Deosarkar ◽  
...  

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 65
Author(s):  
Sergio Bobbo ◽  
Bernardo Buonomo ◽  
Oronzio Manca ◽  
Silvio Vigna ◽  
Laura Fedele

Nanofluids are obtained by dispersing nanoparticles and dispersant, when present, in a base fluid. Their properties, in particular their stability, however, are strictly related to several other parameters, knowledge of which is important to reproduce the nanofluids and correctly interpret their behavior. Due to this complexity, the results appear to be frequently unreliable, contradictory, not comparable and/or not repeatable, in particular for the scarcity of information on their preparation. Thus, it is essential to define what is the minimum amount of information necessary to fully describe the nanofluid, so as to ensure the possibility of reproduction of both their formulation and the measurements of their properties. In this paper, a literature analysis is performed to highlight what are the most important parameters necessary to describe the configuration of each nanofluid and their influence on the nanofluid’s properties. A case study is discussed, analyzing the information reported and the results obtained for the thermophysical properties of nanofluids formed by water and TiO2 nanoparticles. The aim is to highlight the differences in the amount of information given by the different authors and exemplify how results can be contradictory. A final discussion gives some suggestions on the minimum amount of information that should be given on a nanofluid to have the possibility to compare results obtained for similar nanofluids and to reproduce the same nanofluid in other laboratories.


Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 816 ◽  
Author(s):  
Teresa Aguilar ◽  
Ivan Carrillo-Berdugo ◽  
Roberto Gómez-Villarejo ◽  
Juan Gallardo ◽  
Paloma Martínez-Merino ◽  
...  

Nanofluids are systems with several interesting heat transfer applications, but it can be a challenge to obtain highly stable suspensions. One way to overcome this challenge is to create the appropriate conditions to disperse the nanomaterial in the fluid. However, when the heat transfer fluid used is a non-polar organic oil, there are complications due to the low polarity of this solvent. Therefore, this study introduces a method to synthesize TiO2 nanoparticles inside a non-polar fluid typically used in heat transfer applications. Nanoparticles produced were characterized for their structural and chemical properties using techniques such as X-ray Diffraction (XRD), Raman spectroscopy, Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The nanofluid showed a high stability, which was analyzed by means of UV-vis spectroscopy and by measuring its particle size and ζ potential. So, this nanofluid will have many possible applications. In this work, the use as heat transfer fluid was tested. In this sense, nanofluid also presented enhanced isobaric specific heat and thermal conductivity values with regard to the base fluid, which led to the heat transfer coefficient increasing by 14.4%. Thus, the nanofluid prepared could be a promising alternative to typical HTFs thanks to its improved thermal properties and high stability resulting from the synthesis procedure.


Author(s):  
Mohit Gupta ◽  
Devraj Singh ◽  
Shakti Pratap Singh ◽  
Ashish Mathur ◽  
Shikha Wadhwa ◽  
...  

In present investigation, TiO2 nanostructures were synthesized via simple sol-gel technique and characterized with XRD, SEM-EDX, HRTEM and UV-visible spectroscopy techniques. The temperature and concentration dependence of thermal conductivity enhancement and ultrasonic velocity have been explored in ethylene glycol (EG)-based TiO2 nanofluids. The obtained results showed 24% enhancement in thermal conductivity at higher temperature (80°C) of base fluid ethylene glycol by adding 1.0 wt.% of TiO2 nanoparticles. The behaviour of thermal conductivity enhancement and ultrasonic velocity with temperature in prepared nanofluids has been explained with help of existing phenomena. The increase the ultrasonic velocity in ethylene glycol with TiO2 nanoparticles shows that strong cohesive interaction force rises among the nanoparticles and base fluid. These results divulge that TiO2 nanoparticles can be considered for the applications of next-generation competent heat transfer in nanofluids.


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