Preliminary design and performance analysis of a radial inflow turbine for a large-scale helium cryogenic system

Large-scale helium cryogenic systems are widely used in superconducting systems, nuclear fusion engineering, space exploration and large scientific engineering, etc. However, its energy efficiency is quite low due to the extremely low operation temperature. The helium turbine constitutes the most vital component of a large-scale helium cryogenic system. Thus, it is essential to develop a high efficiency helium turbine in order to improve the energy efficiency of the cryogenic helium system. In this paper, a high speed radial micro turbine with the splitter blade was designed for a 40 L/h helium liquefier with Claude cycle. The turbine is designed for inlet and outlet temperatures of 14.4 K and 9.4 K respectively. The design speed of the turbine is 223570 rpm due to the small mass flow rate and impeller diameter. A one-dimensional mean line optimal design approach for radial inflow turbine is adopted in this study. Furthermore, detailed three-dimensional viscous numerical simulations are conducted in order to verify the one-dimensional optimal approach in design condition and predict the performance of the designed turbine in off-design conditions. The results indicate that the optimal helium radial inflow turbine for the design and off-design conditions can be designed through applying the proposed analysis method. (C) 2018 Elsevier Ltd. All rights reserved.