Performance of a natural convection circulation system for supercritical fluids

Syouichirou Yoshikawa, Richard L. Smith, Hiroshi Inomata, Yukihiko Matsumura, Kunio Arai

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)


A closed-loop circulation system for supercritical fluids that operates on the principle of density differences induced by a heating and a cooling source has been developed. Performance of the system was determined by measuring average flow velocities for CO2 over a range of conditions from 7.8 to 15 MPa and from 15 to 55 °C for the given initial loading densities, ρini, of 550-800 kg/m3 and density differences, Δρeff, between heating and cooling sources of the loop of 62-121 kg/m3. One-dimensional finite-difference simulation could predict the velocities at most conditions to within 35%. The flow rates achieved in the system could be correlated in terms of Grashof and Prandtl numbers and a dimensionless effective density difference between heating and cooling sources to within 25% and by an empirical equation in terms of the system pressure, loaded density and heating and cooling source average density difference to within 10%. Average flow velocities as high as 4 m/min could be obtained with heating and cooling source (wall) temperature differences of 3-8 °C. The system should find use in applications such as extended-time extractions, sample preparation and enrichment for analytical applications, catalytic reactions and for transporting slurry suspensions and solutions.

Original languageEnglish
Pages (from-to)70-80
Number of pages11
JournalJournal of Supercritical Fluids
Issue number1
Publication statusPublished - 2005 Nov


  • Circulation system
  • Natural convection
  • Supercritical carbon dioxide
  • Thermal-driven


Dive into the research topics of 'Performance of a natural convection circulation system for supercritical fluids'. Together they form a unique fingerprint.

Cite this