# As far as the ultra high

Downward flow:equation(24)NuNuf=1+(Bo∗)0.1C‾pCpb-0.3ρwρb0.5NuNuf-20.46whereequation(25)Nuf=0.0183Reb0.82Prb0.4ρwρb0.3C¯pCpbn·FTDequation(26)FTD=1+2.35Prf-0.4Ref-0.15(x/d)-0.6exp(-0.39Ref-0.1·x/d)

Fig. 20 presents comparison between the current experimental data and the correlation’s result. Jackson’s correlation, Eq. (21), captures 90% of the data within Indoximod accuracy of +50% and −20%, while the Eqs. (24) and (25) capture 90% of the data within an accuracy of ±30%.

Fig. 20. Comparison of predicted data from two correlations with experimental data.Figure optionsDownload full-size imageDownload as PowerPoint slide

The experimental data was analysed to develop new local Nusselt number correlation for turbulent heat transfer with buoyancy effects for n-decane at supercritical pressures flowing in vertical small circular tubes based on the Eqs. (24) and (25). The modified correlation is:equation(27)NuNuf=1+A·Bo∗c¯pcpbaρρbbNuNuf-20.46where Nuf is mitosis given by Eqs. (26) and (27), andA=-8.45×105,a=-2.23,b=0.14for upward flowA=3.62×105,a=-2.75,b=-1.84for downward flow