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THE ROLE OF OPERATIONAL VARIABILITY ON THE NON-IDEAL FLOW IN SUPERSONIC TURBINES

5th International Seminar on ORC Power Systems. September 9-11, 2019, Athens, Greece. THE ROLE OF OPERATIONAL VARIABILITY ON THE NON-IDEAL FLOW IN SUPERSONIC TURBINES FOR SUPERCRITICAL ORGANIC RANKINE CYCLES. Alessandro Romei | Davide Vimercati | Alberto Guardone | Giacomo Persico.

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THE ROLE OF OPERATIONAL VARIABILITY ON THE NON-IDEAL FLOW IN SUPERSONIC TURBINES

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  1. 5th International Seminar on ORC Power Systems September 9-11, 2019, Athens, Greece THE ROLE OF OPERATIONAL VARIABILITY ON THE NON-IDEAL FLOW IN SUPERSONIC TURBINES FOR SUPERCRITICAL ORGANIC RANKINE CYCLES Alessandro Romei|Davide Vimercati | Alberto Guardone | Giacomo Persico

  2. motivation – supercritical ORC systems • Possible advantages • Higher cycle efficiency • Higher specific work • Lower Primary Heat Exchanger dimension 4 T (K) 5 3 but… complex thermodynamic region 6 2 1 s (J/(kg K)) 1 Compressibilityfactor 4 4* 0

  3. motivation – supercritical ORC systems • Possible advantages • Higher cycle efficiency • Higher specific work • Lower Primary Heat Exchanger dimension 4 T (K) 5 3 but… complex thermodynamic region 6 2 1 s (J/(kg K)) 1 4 Fundamental derivative of gasdynamics 4* 0

  4. gasdynamic regime based on • Non-monotonic Mach number • Non-ideal oblique shocks • Strong variation of nozzle area with upstream quantities M M A/A* P/PC P/PC ϑ (°)

  5. research questions • Does trigger non-conventional turbine operations? FLUID: MM 1 P = 40 bar P = 8 bar 0 • If so, does affect in-field turbine operations? Design Pressure Real Pressure

  6. research questions • Does trigger non-conventional turbine operations? FLUID: MM 1 P = 40 bar P = 8 bar 0 • If so, does affect in-field turbine operations? Design Pressure Real Pressure

  7. operating regime IDEAL-LIKE

  8. operating regime IDEAL-LIKE NON-IDEAL

  9. Journal of FluidMechanics (JFM) NON-IDEAL

  10. research questions • Does trigger non-conventional turbine operations? FLUID: MM 1 P = 40 bar P = 8 bar 0 • If so, does affect in-field turbine operations? Design Pressure Real Pressure

  11. uncertainty quantification – input distribution Upstream Total Temperature 40 bar 39.5 bar 40.5 bar Upstream Total Pressure Periodic BCs bar Downstream Static Pressure

  12. uncertainty quantification – output distribution Uncertainty Propagation Solver Upstream Total Temperature Polynomial Chaos Representation Cascade Loss Y 40 bar 39.5 bar 40.5 bar Upstream Total Pressure CFD Flow Solver Mass Flow bar Downstream Static Pressure

  13. cascade loss variations IDEAL-LIKE 0.15%pts NON-IDEAL 1.5%pts

  14. influence of input uncertainties on cascade losses Ideal-like Non-ideal Importance

  15. mass flow and loss variations 0.2% 2.0% mass flow 3.0% mass flow 12.0% cascade loss cascade loss IDEAL-LIKE NON-IDEAL

  16. conclusion DIFFERENT TURBOMACHINERY OPERATIONS BASED ON IDEAL-LIKE NON-IDEAL

  17. conclusion DIFFERENT TURBOMACHINERY OPERATIONS BASED ON CASCADE LOSS VARIES 10 TIMES MORE WHEN for against for 0.15%pts 1.5%pts

  18. conclusion DIFFERENT TURBOMACHINERY OPERATIONS BASED ON Ideal-like CASCADE LOSS VARIES 10 TIMES MORE WHEN for against for Non-ideal UPSTREAM TOTAL TEMPERATURE RULES THESE VARIATIONS Importance

  19. THE ROLE OF OPERATIONAL VARIABILITY ON THE NON-IDEAL FLOW IN SUPERSONIC TURBINES FOR SUPERCRITICAL ORGANIC RANKINE CYCLES Alessandro Romei* Davide Vimercati Alberto Guardone Giacomo Persico *Laboratory of Fluid Machines Energy Department  | Politecnico di Milano Via Lambruschini 4, 20156 Milano (IT) Mail: alessandro.romei@polimi.it ANY QUESTIONS?

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