Design of a Wide-Range Centrifugal Compressor Stage for Supercritical CO2 Power Cycles

Abstract

Supercritical carbon dioxide (sCO2) power cycles require high compressor efficiency at both the design point and over a wide operating range. Increasing the compressor efficiency and range helps maximize the power output of the cycle and allows operation over a broader range of transient and part-load operating conditions. For sCO2 cycles operating with compressor inlets near the critical point, large variations in fluid properties are possible with small changes in temperature or pressure. This leads to particular challenges for air-cooled cycles where compressor inlet temperature and associated fluid density are subject to daily and seasonal variations as well as transient events. Design and off-design operating requirements for a wide-range compressor impeller are presented where the impeller is implemented on an integrally geared compressor–expander concept for a high temperature sCO2 recompression cycle. In order to satisfy the range and efficiency requirements of the cycle, a novel compressor stage design incorporating a semi-open impeller concept with a passive recirculating casing treatment is presented that mitigates inducer stall and extends the low flow operating range. The stage design also incorporates splitter blades and a vaneless diffuser to maximize efficiency and operating range. These advanced impeller design features are enabled through the use of direct metal laser sintering (DMLS) manufacturing. The resulting design increases the range from 45% to 73% relative to a conventional closed impeller design while maintaining high design point efficiency.

A review of anti-surge control systems of compressors and advanced fault-tolerant control techniques for integration perspective

“…Five important elements to effectively avoid the surge as used in Anti-Surge Control (ASC) design are explained here [ 12 ]. .…”

“…As the technology of microprocessors arrived, the intensity of the arithmetic calculations increased, the modeling was based on polynomials for the surge limit, and unbalanced control systems were introduced. Surge control of the modern area focuses on maximizing the compressor operating zone [ [12] , [13] , [14] , [15] , [16] ]. The latest techniques of the ASC system can be reviewed in Refs.…”

The influence of low-solidity and slotting combined treatment method of diffuser vanes on performance of centrifugal compressor

“…Casing treatment is a common mean of extending compressor operating range, and study of casing treatment at inlet region of impeller has still been a research hot spot in recent years [9][10][11][12][13][14]. Latest research shows that rotating stall phenomenon is observed in flow channel of vane diffuser of centrifugal compressor [15,16], so studies of casing treatment in diffuser area and its influence on operating stability of compressor have drawn more attention in recent years, but they are still rare.…”