Investigations on ORC radial inflow turbine three-dimensional geometry design and off-design performance prediction

Radial inflow turbine is a critical component in the ORC system, which not only influences the system's thermodynamic performance directly but also dominates the system investment cost. Besides, the ORC system is usually operated under off-design operating conditions. Therefore, the reasonable design of the radial inflow turbine and the effective prediction of turbine off-design performance are very important for the ORC system. So based on the authors' previous studies, approaches to designing the turbine's three-dimensional geometry and to predicting the turbine's off-design performance have been discussed in this paper. At first, the parametric modeling for the turbine rotor has been established and the influence of geometric control parameters on turbine performance has been investigated, then the reasonable three-dimensional geometry design of the turbine has been determined. After that, based on the suitable turbine geometry, the off-design performance of the turbine has been investigated. Through the polynomial fitting method, new turbine performance prediction models have been constructed. And the effectiveness of these models has been validated under different organic fluid conditions. This paper presents new perspectives on ORC turbine three-dimensional geometry design and off-design performance prediction, which aims to promote its standardization.