Saturation of enhanced heat transport in thermal convection in the presence of bi-phasic particles

We investigate the enhancement of turbulent heat transport by phase-change bi-phasic particles in a cylindrical Rayleigh–Bénard convection cell. The system comprises deionised water and a small volume fraction ( phi equals 0.86 percent sign ϕ = 0.86 % $\phi = 0.86\,\%$ ) of HFE-7000, a secondary fluid with a low boiling point ( upper T Subscript c r Baseline equals 42 Superscript ring Baseline normal upper C T c r = 42 ∘ C $T_{cr} = 42\,^{\circ }\mathrm{C}$ ). By fixing the top-plate temperature at upper T Subscript t Baseline equals 10 Superscript ring Baseline normal upper C T t = 10 ∘ C $T_t = 10\,^{\circ }\mathrm{C}$ and varying the bottom-plate temperature upper T Subscript b T b $T_b$ , we characterise the global Nusselt number italic Nu Nu $\textit{Nu}$ as a function of the superheat normal upper Delta upper T Subscript italic sup Baseline identical to upper T Subscript b Baseline minus upper T Subscript c r Δ T sup ≡ T b − T c r $\Delta T_{\textit{sup}}\equiv T_b - T_{cr}$ . While the formation of bi-phasic particles initially catalyses heat transport, we report the discovery of a saturation plateau in the enhancement of heat transport for superheats exceeding