Design and Thermal Management of an Additive Manufactured Swirl Injector for High-Pressure Oxy-Methane Combustion

摘要

Pressurized oxy-combustion has the potential to unlock higher efficiencies along with a high carbon capture rate and reduced turbo machinery footprint. The article investigates the design and prototyping of a smart swirl injector with integrated temperature sensing capabilities using laser powder bed fusion (LPBF) additive manufacturing. The primary focus of this work is to design the swirlers for the injector. The injector is designed with a geometric swirl number of 0.9, which turns the flow by approximately 53°. A CFD analysis is performed to verify the actual swirl number at the injector outlet. The analysis shows the actual swirl number at the injector outlet is approximately 0.93. A major goal of this study is to develop a cooling system for the injector. Adiabatic flame temperatures at 20 bar pressure are calculated using NASA CEA thermodynamic analysis, which is used to obtain the radiative heat flux at the injector face. Analytical calculations resulted in 40 GPM water flow requirements for steady-state injector operation. An ANSYS FLUENT analysis is performed to verify the cooling parameters. The heat transfer capability of the cooling channel is verified by the FLUENT analysis. Steady-state temperature is achieved after 2 minutes of simulation. Nickel alloy 718 is used as the injector material. The mean injector body temperature is found to be approximately 350°K. It is found that no part of the injector reached the yielding temperature of nickel alloy 718. Water temperature increases by approximately 6°C after heat removal, and no phase change is observed. Afterward, the injector is designed following LPBF design guidelines for nickel alloy 718.