Effect of the Dilution Ratio and Inlet Structure on High CO2-Diluted Methane Combustion for a Supercritical CO2 Brayton Cycle
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Adding a combustion heater to the traditional supercritical CO 2 (sCO 2 ) Brayton cycle can significantly improve the response speed of the system. This application scenario (combustion conditions) is proposed for the first time, and the influence of different operational and design parameters is numerically studied. The results show that the CO 2 dilution ratio can adjust the O 2 /CO 2 ratio of ‘the combustion stream’, thus changing the flame location and combustion efficiency. For low inlet speed, the flame location will move upstream and become unstable, which is harmful to the injector. In addition, variations in pressure have a limited impact on the flame, except that the inflow velocities and densities are modified accordingly. For the inlet structure, different slope angles can provide different tangential and axial velocities of the inner CO 2 dilution, thus changing the flame characteristic. However, the combustion efficiency can be further improved. By providing a well-stirred mixture in the fuel and oxidizer stream, a recessed fuel injector has evidenced a high improvement in the combustion efficiency. However, adjusting the CO 2 dilution ratio is also needed to optimize the flame location. Finally, the optimal flame location can be obtained with a high efficiency of 95.2%. The current study can provide a basis for the combustion heater’s application in the sCO 2 Brayton cycle.
Source: ACS Omega
Authors: Xuan Wang, Zhi Ling, Fangjia Yan, Haiqiao Wei, Lin Chen
Institutions: Tianjin University, Wuhan Institute of Technology
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,935
Awards: G187363348, G728751680
OpenAlex ID: W4409486803