24
D. P. Barai et al.
Fig. 9 Setup for electrical conductivity measurement. a Electrical circuit with electrode and
b Electrical conductivity metre setup (Sarojini et al. 2013)
Also, other nanofluid environment factors like temperature may prove to be affecting
the electrical conductivity similar to its governing effect on the thermal conductivity.
4.2.1 Concentration of Nanoparticles
It has been already known that the electrical conductivity is due to the electrical double layer formed over the nanoparticles, making them the electric charge carriers.
Many researchers studied the effect of amount of these carriers, that is, nanoparticles dispersed in various kinds of basefluids on their respective nanofluid electrical conductivity (Baby and Ramaprabhu 2010; Glory et al. 2008; White et al.
2011). Increasing the nanoparticle concentration increases the interaction between
the nanoparticles resulting in increase in electrical conductivity (Shoghl et al. 2016).
Liu et al. (2004) investigated the electrical conductivity of the multi-walled carbon
nanotube (MCNT) dispersed in chloroform and toluene and reported that the electrical conductivity of the nanofluids intensifies with increase in the concentration of the
nanofluids. Lisunova et al. (2006) also studied the electrical conductivity of MCNTs
nanofluid using water as a basefluid and Trixton X-305 as a dispersant. It has been
reported that augmentation in the electrical conductivity is more pronounced as the
volume fraction of the nanofluid exceeds 0.01, which happens reportedly due to the
aggregation and percolation behaviour of the nanotubes. The concentration where this
phenomenon occurs is known as the percolation threshold. The nanotubes having a
high aspect ratio form networks and behave as electro-conductive clusters at higher
D. P. Barai et al.
Fig. 9 Setup for electrical conductivity measurement. a Electrical circuit with electrode and
b Electrical conductivity metre setup (Sarojini et al. 2013)
Also, other nanofluid environment factors like temperature may prove to be affecting
the electrical conductivity similar to its governing effect on the thermal conductivity.
4.2.1 Concentration of Nanoparticles
It has been already known that the electrical conductivity is due to the electrical double layer formed over the nanoparticles, making them the electric charge carriers.
Many researchers studied the effect of amount of these carriers, that is, nanoparticles dispersed in various kinds of basefluids on their respective nanofluid electrical conductivity (Baby and Ramaprabhu 2010; Glory et al. 2008; White et al.
2011). Increasing the nanoparticle concentration increases the interaction between
the nanoparticles resulting in increase in electrical conductivity (Shoghl et al. 2016).
Liu et al. (2004) investigated the electrical conductivity of the multi-walled carbon
nanotube (MCNT) dispersed in chloroform and toluene and reported that the electrical conductivity of the nanofluids intensifies with increase in the concentration of the
nanofluids. Lisunova et al. (2006) also studied the electrical conductivity of MCNTs
nanofluid using water as a basefluid and Trixton X-305 as a dispersant. It has been
reported that augmentation in the electrical conductivity is more pronounced as the
volume fraction of the nanofluid exceeds 0.01, which happens reportedly due to the
aggregation and percolation behaviour of the nanotubes. The concentration where this
phenomenon occurs is known as the percolation threshold. The nanotubes having a
high aspect ratio form networks and behave as electro-conductive clusters at higher