Current Technology of Radial-Inflow Turbines for Compressible Fluids

Abstract

Radial turbines have been used for hydraulic, steam, and gas turbine service. In hydraulic turbine practice, a substantial regime of specific speed is reserved exclusively for Francis turbines. No similar situation is found with compressible fluids, where axial turbines are used for the entire specific speed range of practical interest. Francis turbines consistently achieve efficiencies of 90–94 percent, but their counter parts in compressible fluid machines generally are thought to be inferior to axial turbines in performance. Review of available data indicates that radial inflow turbines with compressible fluids can approach or equal the performance of equivalent hydraulic turbines and that, in the specific speed range to which they are applicable, they can match axial turbine performance. Criteria are given which may be used for determination of the suitability of radial turbines for specific requirements.