Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

• Published in: Journal of power sources 2017-10, Vol.365, p.408-418
• Main Authors: Azizi, Mohammad Ali, Brouwer, Jacob
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Dynamic simulation; Hybrid fuel cell gas turbine; Solid oxide fuel cell; Surge/stall dynamics
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.09.010

A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application. •Dynamic operation of a hybrid solid oxide fuel cell gas turbine system was explored.•Computational fluid dynamic simulations of a multi-stage compressor were accomplished.•Stall/surge dynamics in response to a pressure perturbation were evaluated.•The multi-stage radial compressor was found robust to the pressure dynamics studied.•Air flow was maintained positive without entering into severe deep surge conditions.