A new heat propagation velocity prevails over Brownian particle velocities in determining the thermal conductivities of nanofluids

Table 1 Historical development of nanofluidic thermal conductivity models

Author	Thermal conductivity enhancement, k _eff/k _BF
Maxwell [2]
Hamilton and Crosser [3]
Xuan et al. [25]
Jang and Choi [26]
Kumar et al. [27]
Prasher et al. [28, 29]
Patel et al. [30]
Present model

f denotes the volume concentration, n is the empirical shape factor (n = 3 for sphere), and C _α, C _β, C _γ, C _δ and m are empirical constants. Suggested constants [26, 27, 29] are 18 × 10⁶ for C _α, 2.9 to 3.0 for C _β, 40000 for C _γ, and 2.4 to 2.75 for m