Review A brief review on convection heat transfer of fluids at supercritical pressures in tubes and the recent progress Dan Huang a,b , Zan Wu b , Bengt Sunden b,⇑ , Wei Li c a Department of Energy Engineering, Co-Innovation Center for Advanced Aero-Engine, Zhejiang University, Hangzhou 310027, China b Department of Energy Sciences, Lund University, P.O. Box 118, Lund SE-22100, Sweden c Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China highlights  Convection heat transfer at supercritical pressures.  Review and recent progress.  Thermophysical properties at supercritical pressures.  Heat transfer deterioration.  Buoyancy criterion. article info Article history: Received 16 June 2015 Received in revised form 24 September 2015 Accepted 11 October 2015 Available online 11 November 2015 Keywords: Heat transfer Supercritical pressure Parametric effects Heat transfer deterioration Buoyancy criterion abstract This study presents a state-of-the-art overview on heat transfer characteristics of fluids (mainly water, carbon dioxide and hydrocarbon fuels) flowing in smooth tubes and enhanced tubes at supercritical pres- sures and tries to obtain a fundamental understanding of the unique characteristics. Heat transfer in enhanced tubes is much better than that in smooth tubes with a larger pressure drop penalty at super- critical conditions. Thermo-physical properties of fluids at supercritical pressures and relevant paramet- ric effects (e.g., effects of mass flux, heat flux, pressure and flow direction) on heat transfer performance are outlined. Inconsistencies in the literature on heat transfer are emphasized and evaluated. Possible reasons are suggested to explain those inconsistencies. Moreover, the mechanisms for heat transfer dete- rioration at supercritical pressures are discussed and different correlations for predicting heat transfer deterioration are compared and assessed with experimental data. These predictive correlations based on one working fluid cannot be applied directly to other working fluids. Besides, several common buoy- ancy criteria proposed in the literature to distinguish forced convection and mixed convection are eval- uated and show large discrepancies with experimental data. There is no buoyancy criterion developed for hydrocarbon fuels. Future research needs are warranted for heat transfer of near-critical and supercritical fluids. Ó 2015 Elsevier Ltd. All rights reserved. Contents 1. Introduction ......................................................................................................... 495 2. Thermo-physical properties of fluids at supercritical pressures ................................................................ 496 3. Heat transfer in smooth channels ........................................................................................ 496 3.1. Parametric effects on heat transfer ................................................................................. 496 3.1.1. Effects of mass flux....................................................................................... 496 3.1.2. Effects of heat flux ....................................................................................... 498 3.1.3. Effects of pressure ....................................................................................... 498 3.1.4. Effects of flow direction ................................................................................... 499 http://dx.doi.org/10.1016/j.apenergy.2015.10.080 0306-2619/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +46 462228605; fax: +46 462224717. E-mail address: bengt.sunden@energy.lth.se (B. Sunden). Applied Energy 162 (2016) 494–505 Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy