EFFICIENCY CORRELATIONS FOR AXIAL TURBINES IN ORC FIELD

asme-orc2015 Tracking Number 83

This work aims at defining a set of general correlations for the estimation of axial-flow turbine efficiency in Organic Rankine Cycle (ORC) field. A dedicated numerical tool is used for the optimization of several hundreds of turbines and the results are presented in specific parameters (SP, V_r and Ns) according to similarity rules. The analysis is carried out for single, two and three stages turbines. For each case a correlation of efficiency at optimal rotational speed is calibrated in function of the equivalent single stage SP and the total isentropic V_r. Three sensitivity analyses are proposed in order to highlight the effects of each single parameter on stage efficiency. Finally, the model is validated on four turbines comparing the results from the correlation with those attainable with a dedicated numerical tool for the turbine design. REFERENCES [1] Smith, M.H. A simple correlation of turbine effciency. : Journal of Royal Aeronautical Society, 1965. p. 467. Vol. 69. Cc [2] Baljè, O.E., Binsley, R.L. Axial turbine performace evaluation: part B - optimization with and without constraints. : ASME Journal of Engineering for Power. pp. 349-360. [3] Craig, H.R.M., Cox, H.J.A. Performance estimation of axial flow turbines. : Proceedings of he institution of mechanical engineers. pp. 407-423. Vol. 185 32/71. [4] Dixon, S. L., Eng., B. Fluid Mechanics, Thermodynamics of urbomachinery, Fifth Edition. s.l. : Eselvier, 1998.