Characteristics of a turbomachine impeller with radial blades of symmetrical profile in compressor mode

The paper presents the results of studies of the characteristics of a turbomachine impeller with radial blades of a symmetrical profile, in which some of the blades operate in turbine mode, and some of the blades operate in compressor mode. This combination of modes is provided by partial supply of the working gas. The characteristics of the compressor part of the blades were determined by the conditions of the energy and kinematic balances of the turbine and compressor blades. The dependences of the specific powers of turbine and compressor parts for different blade installation angles on the speed characteristic determining the operating mode of the turbine part are obtained. The influence of the blade installation angle on the total efficiency, which characterizes the losses during the energy conversion of the velocity pressure incident on the turbine blades into the energy of the working fluid at the outlet of the interblade channels of the compressor part, is determined. The dependence of the specific consumption of the working gas on the blade installation angle was obtained. The characteristics of the compressor part of the impeller are presented as dependencies on the flow coefficient. It was found that for each blade installation angle there are flow coefficients corresponding to the maximum degree of pressure increase and the maximum efficiency of the compressor part.