Characterization of Nonequilibrium Condensation of Supercritical Carbon Dioxide in a de Laval Nozzle

Claudio Lettieri, Derek Paxson, Zoltan Spakovszky, Peter Bryanston-Cross

Research output: Contribution to journalArticleScientificpeer-review

39 Citations (Scopus)


Carbon capture and storage could significantly reduce carbon dioxide (CO2) emissions. One of the major limitations of this technology is the energy penalty for the compression of CO2 to supercritical conditions. To reduce the power requirements, supercritical carbon dioxide compressors must operate near saturation where phase change effects are important. Nonequilibrium condensation can occur at the leading edge of the compressor, causing performance and stability issues. The characterization of the fluid at these conditions is vital to enable advanced compressor designs at enhanced efficiency levels but the analysis is challenging due to the lack of data on metastable fluid properties. In this paper, we assess the behavior and nucleation characteristics of high-pressure subcooled CO2 during the expansion in a de Laval nozzle. The assessment is conducted with numerical calculations and corroborated by experimental measurements. The Wilson line is determined via optical measurements in the range of 41-82 bar. The state of the metastable fluid is characterized through pressure and density measurements, with the latter obtained in a first-of-its-kind laser interferometry setup. The inlet conditions of the nozzle are moved close to the critical point to allow for reduced margins to condensation. The analysis suggests that direct extrapolation using the Span and Wagner equation of state (S-W EOS) model yields results within 2% of the experimental data. The results are applied to define inlet conditions for a supercritical carbon dioxide compressor. Full-scale compressor experiments demonstrate that the reduced inlet temperature can decrease the shaft power input by 16%.

Original languageEnglish
Article number041701
Number of pages11
JournalJournal of Engineering for Gas Turbines and Power
Issue number4
Publication statusPublished - 1 Apr 2018


Dive into the research topics of 'Characterization of Nonequilibrium Condensation of Supercritical Carbon Dioxide in a de Laval Nozzle'. Together they form a unique fingerprint.

Cite this