One-Dimensional Primary Design for Single Axial Turbine Being Used for Small-Scale Organic Rankine Cycle

Organic Rankine cycle(ORC) is one of the efficient technical means to use low-grade energy. Based on certain heat source conditions, many researchers focus on selecting working fluids and designing efficient thermal cycle systems, and less literature focuses on the research of expanders. The expander is the output power component of the thermal cycle system, which has a significant impact on the performance and operating parameters of the system. However, the thermodynamic properties of working fluid have a great influence on turbine efficiency, so design parameters are critical to ensure a high efficiency of axial turbine. On the other hand, due to the actual gas properties of organic working fluid vapors in small-scale ORC applications, some design efficiency relationships of gas turbine are not suitable to organic working fluid turbines. The expanders for small-scale ORCs are mainly volumetric, with some radial turbines and few axial turbines. Therefore, this paper uses a one-dimensional mean line method to design a single-stage axial-flow turbine for small-scale ORCs. The basic dimensions of the turbine are obtained and the characteristics of the turbine under design conditions are analyzed. Through the performance analysis in design conditions, it provides a theoretical reference for the design of single-stage axial flow turbines for small-scale ORCs.