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 % φ = 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 Tcr = 42\,∘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 Tₜ = 10\,∘C and varying the bottom-plate temperature upper T Subscript b T b Tb , we characterise the global Nusselt number italic Nu Nu 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 Δ Tₛᵤₚ≡ Tb - Tcr . 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