Advancement in energy storage technology is critical in the transition to increased renewable energy sources. The thermodynamic properties of S-CO2 allow for high thermal efficiency and power density potential in turbomachinery design. Relative to the Steam Rankine and Air Brayton cycles, S-CO2 cycles benefit in performance, size, and cost.
As S-CO2 gains acceptance in the industry, research must be conducted to understand the potentials and limitations of this new technology; this is key to the eventual commercial viability of S-CO2 applications. Currently, applications of S-CO2 in turbomachinery are limited to centrifugal design due to the complex fluid properties and flow interactions.
Advancements in compressor design now allow for the intelligent navigation of this complex design space. Optimization tools are utilized to evaluate parametrically defined blades in S-CO2 working fluid to explore advanced, high-performance geometries.
The first axial S-CO2 compressor is designed using this optimization based methodology. This design is the scaled 9 MW 3 stage version of a larger 100 MW 9 stage compressor that will be used for an energy storage application. The adiabatic efficiency of the first stage design is estimated at 91.6% with 3.14 MW of power at 19,800 rpm. The blade height at the rotor leading edge is 3.28 cm.
The first stage of the scaled 9 MW 3 stage compressor will be tested at the University of Notre Dame Turbomachinery Lab; testing of the complete 3 stage machine will follow the single stage testing.
Stage one design drawings have been finalized and submitted for manufacturing. The IGV and Stator 1 have been manufactured and received by the University of Notre Dame Turbomachinery Lab for assembly and testing in the Fall of 2022.
This paper describes the findings of detailed simulations performed to investigate the impact of seal teeth cavity leakage flow on the aerodynamic and thermal performance of a three-stage supercritical CO2 axial compressor. The study compares a shrouded stator configuration (with cavities) to a cantilevered stator configuration (without cavities) to highlight their differences. High-fidelity computational fluid dynamics simulations were performed using non-linear harmonic (NLH) and mixing plane assumptions, considering various possible rotor/stator interface configurations for mixing plane calculations. The key performance parameters for each case were compared, and the best-performing configuration selected for further analysis. The individual stage performance parameters are also examined and compared between the cantilevered and shrouded configurations. It was observed that in the shrouded case, the leakage flow enters the cavity downstream of the stator trailing edge and gets entrained into the primary flow upstream of the stator, leading to boundary layer changes at the hub and degradation of stator and downstream rotor performance. Vortical flow structures were also observed in the stator wells, which tended to change the flow angles around the region, thereby affecting mixing and velocity distribution, resulting in a slight deterioration of compressor performance. Additionally, the study examines windage heating due to shear work from rotating walls, including the seal teeth surface. The amount of shear work done on the leakage flow and the corresponding rise in fluid temperature were quantified, tabulated, and further compared with a simple analytical model, showing good agreement between them and, hence, validating the numerical approach used.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.