Newly obtained correlations Eq. (19) were confirmed by calculating
Nusselt numbers using Reynolds numbers and Prandtl numbers
presented in Tables 2 and 3. The calculation results of Eq. (19),Nucorr, are shown in Fig. 8 against Nusselt numbers obtained for each calculation through Eq. (4), NuCFD. In addition, Nucorr shows good agreement with NuCFD; the deviations of the correlations are r = 1.47% for the water side and r = 0.90% for the CO2 side. The Nusselt numbers calculated from Ref. [8], Utamura and Dittus–Boelter correlations, are also depicted in Fig. 8. The new correlations as shown in Eq. (19), can reproduce the Nusselt number best among these correlations.