Advances in aerodynamic, structural design and test technology of variable geometry turbines

The variable geometry turbine is one of the technical means to effectively improve the part-load performance, part-load condition stability and manoeuvrability of gas turbines, aeroengines or even turbochargers. However, the design of the variable geometry turbine is very difficult, and the decrease in efficiency offsets some of the engine cycle benefits caused by turbine variable geometry. Therefore, it is very necessary to carry out research on variable geometry turbine technology so that the technology can be successfully applied to various types of gas turbine engines as soon as possible. This paper summarizes and analyzes the recent advances in the field of aerodynamic, structural design and test of variable geometry turbines. This review covers the following topics that are important for variable geometry turbine designs: (1) flow mechanisms and aerodynamic characteristics, (2) wide-condition aerodynamic design method for turbine blades, (3) variable vane turning design method, (4) structural design technology of variable vane system and (5) aerodynamic characteristics and reliability test technology for variable geometry turbines. The emphasis is placed on the variable vane turning design method. We also present our own insights regarding the current research trends and the prospects for future developments.