Effect of volume concentration and temperature on viscosity and surface tension of graphene–water nanofluid for heat transfer applications

Abstract

In the present study, the effect of volume concentration (0.05, 0.1 and 0.15 %) and temperature (10-90°C) on viscosity and surface tension of graphene-water nanofluid has been experimentally measured. The sodium dodecyl benzene sulfonate is used as the surfactant for stable suspension of graphene. The results showed that the viscosity of graphene-water nanofluid increases with an increase in the volume concentration of nanoparticles and decreases with an increase in temperature. An average enhancement of 47.12 % in viscosity has been noted for 0.15 % volume concentration of graphene at 50°C. The enhancement of the viscosity of the nanofluid at higher volume concentration is due to the higher shear rate. In contrast, the surface tension of the graphenewater nanofluid decreases with an increase in both volume concentration and temperature. A decrement of 18.7 % in surface tension has been noted for the same volume concentration and temperature. The surface tension reduction in nanofluid at higher volume concentrations is due to the adsorption of nanoparticles at the liquid-gas interface because of hydrophobic nature of graphene; and at higher temperatures, is due to the weakening of molecular attractions between fluid molecules and nanoparticles. The viscosity and surface tension showed stronger dependency on volume concentration than temperature. Based on the calculated effectiveness of graphene-water nanofluids, it is suggested that the graphene-water nanofluid is preferable as the better coolant for the real-time heat transfer applications.

Review on the recent progress in the preparation and stability of graphene-based nanofluids

“…Baby and Sundara [97] presented a technique for preparing the copper oxidedecorated graphene-dispersed nanofluids. Firstly, carboxyl Silicone oil Functionalized GNS MHM, then synthesized 0.0-0.07 mass% [130] EG DI NDG-MNT HM, then CVD 0.005-0.03 vol% 0.005-0.02 vol% [131] DW + SUR GNSs SBM 0.05 mass% [132] Kerosene + SUR GNPs SBM 0.005-0.2 mass% [133] DW GNSs SBM 0.003-0.009 mass% [134] DW + SUR GR SBM 0.05-0.15 mass% [192] EG GO MHM 0.1-5 vol% [193] DW Phenyl-sulfonic-functionalized GR SBM 0.02-1 vol% [194] DI GO MHM 0.005-0.01 mass% [195] EG GO MHM 0.01-0.05 mass% [196] DW GNSs SBM 0.003-0.006 mass% [197] DI GNPs SBM 0.025-0.1 mass% [198] DW GNPs SBM 1 mass% [199] DW + SUR GNPs SBM 0.05-0.15 vol% [200] DW GNSs SBM 0.001-0.01 mass% GR graphene, GI graphite, NP nanoparticle, SUR surfactant Then, the functionalized graphene was utilized to decorate the CuO nanoparticles with the help of CuCl 2 and NaBH 4 and NaOH. Baby and Ramaprabhu [98] and Kole and Dey [105] utilized dried GO to produce hydrogen exfoliated graphene in hydrogen at 200 °C.…”

Recent advances in modeling and simulation of nanofluid flows-Part I: Fundamentals and theory

“…Surface tension is a crucial parameter in the analysis of heat transfer phenomena such as pool boiling since it affects surface wettability and bubble growth [146]. On the measurement of surface tension of nanofluids, Ahammed et al [147] measured the surface tension of graphene/water nanofluids and showed that with increasing the temperature and nanofluid concentration the surface tension decreases. They developed a correlation as:…”

Viscosity and thermal conductivity of MgO–EG nanofluids

“…It was also confirmed that the empirical model proposed by Adio et al (13) describes the enhancement of the viscosity in MgO-EG nanofluids correctly. It was presented that it is possible to model an increase of the viscosity by using modified K-D model (7) a second degree polynomial (12). It has been shown that the enhancement of thermal conductivity can be modeled also by using a second degree polynomial (20), and the classical models of thermal conductivity do not describe the MgO-EG nanofluids correctly.…”

“…The increase in thermal conductivity of nanofluids containing various types of nanoparticles was intensively studied [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. However, when planning the practical use of nanofluids, it should be taken into account that with increasing concentration of the nanoparticles in a liquid its viscosity increases [19,20,26].…”