Efficiency analysis of an incompressible-flow ejector using Computational Fluid Dynamics (CFD) simulations and mathematical modeling.

• Autor(a) principal: Marum, Victor Jorge de Oliveira
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/3/3134/tde-24052021-094502/
• topic: Análise de eficiência; Carbon capture and storage; Carbono (Armazenagem); Computational Fluid Dynamics; Dinâmica dos fluidos computacional; Dióxido de carbono (Redução); Efficiency analysis; Ejector; Ejetor

Carbon Capture and Storage (CCS) is capable of delivering significant emissions reduction of carbon dioxide (CO2) into atmosphere. In CCS applications, CO2 must be compressed at high pressures to be reinjected into depleted hydrocarbon reservoirs by a mechanical machine, such as ejectors. In this work, a quasi-one-dimensional (1D) mathematical approach from literature was employed to perform a theoretical analysis of an incompressible-flow ejector, using results from Computational Fluid Dynamics (CFD) simulations as input data. In order to properly express the non-uniformity of the velocity and pressure profiles at the ejector sections, kinetic-energy and pressure correction factors were employed in the results from CFD simulations. In addition, a new efficiency approximation is proposed including those correction factors on its formulation. Finally, a sensitivity analysis was conducted aiming to investigate the influence of each ejector component on its performance. The results have shown that the mathematical approach from literature presents good agreement with the CFD results and could accurately delimit the ejector\'s envelope of operation and predict its efficiency peak. And the new approximation has presented lower deviation from CFD results for specific entrainment ratio (M) values. The plots of the pressure and velocity profiles indicated that the pressure stabilization occurs inside the mixing section and the velocity stabilization takes place inside the diffuser. The sensitivity analysis pointed out that the nozzle geometry affects the ejector\'s efficiency curve for all while geometries of the suction chamber, mixing section and diffuser affect the efficiency curve only for higher and intermediate M.