A STUDY ON NUMERICAL MODELING OF SUPERCRITICAL CO_2 FLOW IN CENTRIFUGAL COMPRESSORS

摘要

Using supercritical carbon dioxide (SC-CO_2) as working fluid for energy systems has many benefits including high efficiency, compact turbomachinery and the abundance of CO_2. A very important issue for design optimization and performance analysis of future supercritical Brayton cycles is concerned with the SC-CO_2 flow inside high speed compressor/turbine machinery. The objective of this paper is to present a novel modeling approach to numerical simulations of the flow inside a high-speed compact compressor. The approach capitalized on using three different physical and mathematical 1-D models (compressible and incompressible flow using actual properties of SC-CO_2 and a compressible ideal gas model) to verify the predictive capabilities of a 3-D incompressible model. The latter model has been used to perform simulations for a complete multidimensional detailed model of a SC-CO_2 compressor. It has been shown that the model's predictions are consistent with the published technical data for the compressor employed in the experimental loop developed at SANDIA National Laboratories.