Fig. 4

Thermal conductivity of GOnP/(EG + W) nanofluid set. Temperature dependence at different mass concentrations: diamond, base fluid 0%; circle, 0.10%; triangle, 0.25%; and square, 0.50%. The dashed lines represent the fitted Nan model [55], Eqs. (2–3). The inset shows the thermal conductivity enhancements of the nanofluids in relation to the base fluid, 10² (k _nf − k _bf)/k _bf, at 303.15 K (white bars) and 343.15 K (gray bars)