Application of Bethe-Zel'dovich-Thompson Fluids in Organic Rankine Cycle Engines

Thenovel concept ofimproving organicRankinecycleengines (ORCEs)by exploiting the unusual e uid dynamic behaviorofaspecialclassofworkinge uidsknownasBethe ‐Zel’dovich‐Thompson(BZT)e uidsisexplored.ORCEs are currently manufactured and used for numerous remote terrestrial applications requiring reliable, unattended power.OneofthemajorlossmechanismsinORCEsisshockwavesgenerated intheturbinestage.Operatingunder theproperthermodynamicconditions, a BZT working e uid can potentially weaken oreliminate shock waves. This would reduce losses due to both the wave drag from shocks as well as losses from boundary-layer separation due to shock ree ections on the turbine blades. Two-dimensional e owe elds through realistic symmetric impulse turbinecascades arecompared using a e ux-limited, e nite differencenumerical schemeto assess differences in e ow efe ciencies. Resultsshowsignie cantimprovementsin turbineefe cienciesforBZTworkinge uidsoverconventional ORCE working e uids.