Direct Numerical Simulation Study for Fluid-to-Fluid Scaling for Fluids at Supercritical Pressure

A successful general fluid-to-fluid similarity theory for heat transfer at supercritical pressure

“…Then, a recent paper presented by the group of Prof. He [25] showed Direct Numerical Simulation (DNS) data which perfectly supported the old rationale proposed in the mentioned less successful applications of References [ 15 , 16 ], just corrected by imposing also the equality of the Reynolds numbers at channel inlet. Discussing these new results, a step forward in understanding the capabilities of the already proposed similarity theory was made, leading to a common paper [17] .…”

“…The strategy of changing the pipe diameter was used by Prof. He and his group in performing the DNS analyses [25] which triggered the common paper [17] , owing to their choice to preserve also the inlet Reynolds number in addition to the inlet Froude number.…”

“…This was obtained by reflecting on the exceptionally similar results obtained by the DNS calculations presented by Prof. He and his group [25] . This reflection, reported in [17] , allowed reaching the conclusion that the most important contributor to the exceptional performance of the similarity theory, adopted in close similarity with what proposed in [15] , was the selection of operating conditions in a window of dimensionless specific enthalpy in which the four selected fluids had nearly the same Prandtl number.…”

A successful local fluid-to-fluid similarity theory for heat transfer to supercritical pressure fluids: merits and limitations

“…Recently, He et al [14] re-assessed the work by Ambrosini [8] by performing DNS analyses for the same four fluids and the same pressures considered in that paper and making use of the same similarity principles, with the noticeable addition of the preservation of the value of the inlet Reynolds number as a further constraint.…”

“…While Ambrosini [8] mostly preserved the dimensionless inlet subcooling, the power-to-flow ratio and the Froude number, also making sensitivity analyses with a scaled geometry that implied a rough correspondence of the inlet Peclet number, He et al [14] changed their geometry case by case in order to also impose the same inlet Reynolds number. As a result, while Ambrosini [8] had only a rough qualitative matching of the scaled behaviour among the different fluids, He et al [14] actually reported rather improved similar trends of dimensionless variables at the wall as well as in the bulk fluid, in an exceptional display of good coherence.…”