Performance validation of a large scale helium turboexpander for cryogenic applications through CFD analysis

Abstract

The demand of low temperature for superconducting magnets used in high energy physics applications has necessitated the need for helium refrigeration and liquefaction cycles with improved efficiency. Any attempt of designing a plant with improved thermodynamic performance may call for improvement of efficiency of turboexpanders. Developing a design strategy for helium turboexpander with better efficiency demands in depth understanding of the complex flow physics. Computational Fluid Dynamics (CFD) is a useful tool to find the details of the flow and evolve a design strategy leading to improved performance of the machine. In the present work, 3D CFD analysis of a large scale cryogenic helium turboexpander designed and tested at BARC was performed using Ansys CFX®. Different aspects of computation procedure such as turbulence models, and models for rotor stator interface have been discussed. Results obtained from simulation were compared with experimental results for validation.