Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
Comparisons of heat transfer and pressure drop
experimental data and correlations for supercritical CO2 cooling
are presented in this article. First, the physical and transport
properties of CO2 at supercritical conditions are discussed and
then their influence on heat transfer and pressure drop. Then,
comparison and analysis relative to the available heat transfer
and pressure drop correlations for supercritical CO2 cooling
were done where possible. Noting the lack of all pertinent
experimental details required to use the data published in many
of the available studies, comments are given on how to reduce
and present supercritical CO2 experimental data properly in the
future. Simulations by the available heat transfer correlations
were performed and the predicted results were compared with
each other. Based on the comparisons and analysis, it is
recommended that further efforts be made to develop improved
heat transfer methods for supercritical CO2 cooling based on a
more accurate database in the future. To achieve this, more
careful experiments should be done in both macro- and microchannels
over a wide range of test parameters, including the
effect of oil. In addition, several experimental studies show that
the Blasius equation works well for pressure drop of CO2
cooling in the supercritical region. More careful experimental
data are still needed to further validate this conclusion.
