Real-gas effects: The state of the art of organic Rankine cycles

Organic Rankine Cycles (ORC) are one of the most notable methods for waste heat recovery at low to medium temperatures which leads to a cleaner environment. Organic vapors with high molecular weight are the working fluid of the ORC. Using such substances leads to non-ideal or non-classical gas dynamics inside the expander, where transonic and supersonic regimes occur. This paper presents a comprehensive review of the literature related to the real-gas effects with applications of ORCs. The review includes numerical simulations and experimental approaches. It is shown that the main gap in this field is quantitative experimental results for the flow field. However, recently a free jet of such flows investigated by particle image velocimetry but, this experiment is done for a specific substance. Therefore, a number of research opportunity in this field will be remained for future studies. (C) 2020 Elsevier Ltd. All rights reserved.