Development of a Novel Axial Compressor Generation for Industrial Applications: Part 1 — Compressor Design and Performance

Abstract

An industrial axial compressor has to meet a wide range of operation requirements and therefore must run within the whole compressor map without restrictions at an overall high level of efficiency. Additionally a robust design is required allowing a continuous operation of up to five years under industrial boundary conditions without inspection. These requirements led the industrial turbomachinery market to be generally conservative and sensitive to every single change through modern compressor development. The consequence for industrial compressor designs are, that these have made only moderate development steps during the last 50 years. This paper deals with a novel hybrid axial flow compressor, which combines the advantages of an conventional industrial compressor, such as good operating range and efficiency, with the advantages of gas turbine compressors, mainly the higher power density resulting in a higher stage pressure ratio. Furthermore, the surge robustness of the novel compressor blading has been strongly improved. Starting from scratch, the development began with comprehensive matrix studies in all areas of the design, taking into account aerodynamics, mechanics, rotor dynamics and power density in order to ascertain the overall optimum for this new hybrid generation. State of the art CFD analysis has been intensively used to optimize the compressor blading as well as the flow behavior of inlet and exit for the specified requirements and different compressor control mechanisms. The novel hybrid compressor is designed for a volume flow of 930 000 m3/h and allows a scaling from 100 000 up to 1 500 000 m3/h of air. To verify the design, a rig — downscaled by the factor of 3 — was tested. The rig was intensively instrumented with thermocouples and pressure probes, a torquemeter, strain gauges, tip-timing probes, and transient pressure transducers. Besides the measurement of blading performance, inlet and exit flange-to-flange instrumentation has been used to collect performance data under a variety of industrial operating conditions. The compressor behavior will be presented with a focus on aerodynamic aspects. The analytical and experimental data will be discussed in detail.